Managing Irregular Freelance Income: Complete Guide to Financial Stability

Managing Irregular Freelance Income: Complete Guide to Financial Stability

The feast-or-famine cycle is freelancing's biggest financial challenge. One month you're swimming in project payments, the next you're scraping by on leftovers.

Here's the brutal truth: Traditional budgeting advice doesn't work for irregular income. You can't just "spend 30% on housing" when you don't know what your income will be next month.

This guide gives you a battle-tested system for managing irregular freelance income - complete with real numbers, spreadsheet templates, and strategies used by financially stable freelancers.

The Reality of Irregular Freelance Income

Let's start with what irregular income actually looks like for most freelancers.

Income Patterns from Real Freelancers

Sarah (Graphic Designer) - 2025 Monthly Income:

• January: $3,200
• February: $1,800
• March: $5,400
• April: $2,100
• May: $4,800
• June: $900
• July: $6,200
• August: $3,400
• September: $2,600
• October: $4,100
• November: $1,200
• December: $3,800

Annual total: $39,500 | Monthly average: $3,292 | Monthly range: $900-$6,200

Marcus (Web Developer) - 2025 Monthly Income:

• Q1: $8,200, $12,400, $4,600
• Q2: $2,800, $9,800, $15,600
• Q3: $6,200, $1,400, $11,200
• Q4: $7,800, $18,400, $4,200

Annual total: $102,600 | Monthly average: $8,550 | Monthly range: $1,400-$18,400

These patterns are typical. Income swings of 300-500% month-to-month are normal, not a sign you're doing something wrong.

Why Freelance Income Is Irregular

Client payment cycles: Net 30, Net 60, or "we'll pay when we feel like it"

Project timing: Lumpy project deliveries create payment clusters

Seasonal demand: Many industries have peak and slow seasons

Contract gaps: Time between finishing one project and starting another

Scope creep and delays: Projects take longer, payments get pushed back

Economic factors: Client budgets freeze, projects get cancelled

Your capacity limits: You can only handle so many projects simultaneously

The key insight: Irregular income isn't a bug in freelancing - it's a feature. Accept it and plan around it.

The Traditional Budget Problem

Standard budgeting advice assumes steady income:

• 50/30/20 rule (needs/wants/savings)
• Fixed monthly allocations
• "Pay yourself first" with automated transfers

This fails spectacularly with irregular income.

When you make $1,200 in November and $6,200 in July, fixed percentages create chaos:

• November: $600 for needs, $360 for wants, $240 for savings (not enough to live on)
• July: $3,100 for needs, $1,860 for wants, $1,240 for savings (lifestyle inflation trap)

You need a different approach.

The Variable Income Management System

Here's the system that actually works for irregular income.

Step 1: Calculate Your Survival Number

Your Survival Number is the absolute minimum you need to cover essential expenses.

Essential expenses only:

• Housing (rent/mortgage, utilities)
• Food (groceries, not dining out)
• Transportation (car payment, gas, insurance)
• Insurance (health, liability)
• Minimum debt payments
• Basic phone/internet

Example calculation:

• Rent: $1,200
• Utilities: $150
• Groceries: $300
• Car payment: $280
• Car insurance: $110
• Health insurance: $320
• Phone: $45
• Survival Number: $2,405

Your Survival Number is your financial floor. Everything else is flexible.

Step 2: Build Your Income Smoothing Buffer

This is different from an emergency fund. It's money that smooths out monthly variations.

Target size: 3-4 months of your Survival Number

Using the example above: $2,405 × 3.5 = $8,418

How it works: In high-income months, you add to the buffer. In low-income months, you withdraw to meet your Survival Number.

Real example using Sarah's income:

The buffer prevents lifestyle whiplash and financial stress.

Step 3: The Four-Bucket System

Divide all income into four buckets with specific purposes:

Bucket 1: Survival (Fixed Amount)

• Always $2,405 (your Survival Number)
• Covers essential expenses
• Never varies regardless of income

Bucket 2: Buffer (Variable)

• Adds to buffer when income is high
• Draws from buffer when income is low
• Goal: Keep buffer at target level

Bucket 3: Taxes (Percentage)

• 25-30% of gross income
• Separate savings account
• Paid quarterly to IRS/state

Bucket 4: Growth & Life (Remaining)

• Business investments
• Discretionary spending
• Additional savings
• Fun money

Example month with $5,400 income:

• Bucket 1 (Survival): $2,405
• Bucket 2 (Buffer): +$995 (to reach target)
• Bucket 3 (Taxes): $1,350 (25%)
• Bucket 4 (Growth): $650

Low month with $1,200 income:

• Bucket 1 (Survival): $2,405 (take $1,205 from buffer)
• Bucket 2 (Buffer): -$1,205
• Bucket 3 (Taxes): $300 (25%)
• Bucket 4 (Growth): $0

Step 4: Income Forecasting and Planning

Track patterns to predict and plan for income variations.

Create an income tracking sheet with:

• Monthly income for past 12-24 months
• Client payment patterns
• Seasonal trends
• Pipeline value and probability

Identify your patterns:

• Seasonal trends: "December is always slow"
• Payment cycles: "Client A always pays 45 days after invoice"
• Project patterns: "Big projects come in Q1 and Q3"

Use patterns for planning:

• Build extra buffer before slow seasons
• Time major expenses for high-income months
• Plan business development during low-revenue periods

Advanced Strategies for Income Smoothing

The 12-Week Rolling Average

Instead of monthly budgeting, use a 12-week rolling average for more stability.

How it works:

1. Calculate your average weekly income over the past 12 weeks
2. Base your spending decisions on this average
3. Update weekly with new data

Example: Weeks 1-12 total income: $18,400 12-week average: $1,533/week Monthly budget basis: $1,533 × 4.33 = $6,638

This smooths out short-term fluctuations while staying responsive to longer trends.

The Peak and Valley Strategy

Plan different financial behaviors for high and low income periods.

High-Income Month Priorities (Above 150% of average):

1. Fill buffer to target level
2. Pay quarterly taxes early
3. Prepay fixed expenses (insurance, subscriptions)
4. Invest in business development
5. Take some profit for yourself

Average Income Month Priorities (75-150% of average):

1. Cover survival needs
2. Set aside taxes
3. Maintain buffer level
4. Normal business operations

Low-Income Month Priorities (Below 75% of average):

1. Cover survival needs from buffer if necessary
2. Minimize discretionary spending
3. Focus on business development and sales
4. Avoid major purchases or commitments

The Profit First Method for Freelancers

Adapt Mike Michalowicz's Profit First system for irregular income.

Traditional approach: Revenue - Expenses = Profit Profit First approach: Revenue - Profit = Expenses

How to apply it:

1. Every payment received gets divided immediately:

   • Profit: 10-15% (pay yourself first)
   • Taxes: 25-30%
   • Operating expenses: 50-60%
   • Buffer: Remaining

2. Use separate accounts for each category

3. Only spend from the operating expense account

4. Transfer profit quarterly to personal account

This ensures you always pay yourself, even in good months when it's tempting to reinvest everything.

Building Multiple Income Streams

Reduce irregularity by diversifying income sources with different patterns.

Income stream types:

Project work (lumpy, high-value):

• Large consulting projects
• Website builds
• Major campaigns

Retainer work (steady, predictable):

• Monthly marketing services
• Ongoing support contracts
• Subscription-based services

Product sales (passive, scalable):

• Digital courses
• Templates and tools
• Affiliate commissions

Example balanced portfolio:

• 60% project work (your main skill)
• 30% retainer work (steady base)
• 10% product sales (upside potential)

This reduces month-to-month swings while maintaining earning potential.

Tax Management with Irregular Income

Irregular income makes quarterly taxes especially tricky. Here's how to handle it.

The Safe Harbor Strategy

Pay 100% of last year's tax liability (110% if you made over $150K) divided by four quarters.

Example:

• 2025 total tax liability: $12,000
• 2026 quarterly payments: $3,000 each
• Pay same amount each quarter regardless of income

Benefits:

• No underpayment penalties
• Predictable cash flow impact
• Simplified planning

Downside:

• May overpay in low-income years
• Requires cash flow management

The Pay-As-You-Go Method

Set aside taxes immediately as percentage of every payment received.

System:

1. Every client payment → immediately transfer 25-30% to tax account
2. Pay quarterly taxes from this account
3. Adjust percentage based on effective tax rate

Benefits:

• Always have tax money available
• Matches tax obligation to income
• No surprises

Challenge:

• Requires discipline with every payment
• Need to track carefully

Use our Tax Calculator to determine your optimal tax set-aside percentage based on your income level and deductions.

Quarterly Tax Planning Calendar

January-March (Q1):

• File prior year return
• Pay Q1 estimated taxes (April 15)
• Update tax percentage if needed

April-June (Q2):

• Review Q1 performance
• Pay Q2 estimated taxes (June 15)
• Adjust strategy if income pattern changed

July-September (Q3):

• Mid-year tax planning
• Pay Q3 estimated taxes (September 15)
• Consider year-end tax strategies

October-December (Q4):

• Pay Q4 estimated taxes (January 15)
• Execute year-end tax moves
• Plan for next year

Emergency Planning for Irregular Income

Standard emergency fund advice (3-6 months expenses) needs modification for irregular income.

The Two-Fund Approach

Fund 1: Income Smoothing Buffer

• Size: 3-4 months of Survival Number
• Purpose: Smooth monthly variations
• Use: Regular draw-downs in low months

Fund 2: True Emergency Fund

• Size: 6-12 months of Survival Number
• Purpose: Major emergencies only
• Use: Job loss, medical emergency, major client loss

Why separate funds:

• Prevents accidentally depleting emergency savings
• Different replenishment priorities
• Psychological clarity about fund purposes

Emergency Scenarios Planning

Scenario 1: Major Client Loss (40%+ of income)

• Immediate: Reduce to Survival Number spending
• Week 1: Activate business development plan
• Month 1: Consider temporary contract work
• Month 3: Reevaluate niche/positioning

Scenario 2: Industry Downturn

• Immediate: Extend cash runway calculations
• Week 1: Network activation and skill assessment
• Month 1: Consider industry pivot or new services
• Month 6: Major career/business model pivot if needed

Scenario 3: Health Emergency

• Immediate: Client communication and project handoff plan
• Week 1: Insurance claims and temporary coverage
• Month 1: Return-to-work planning
• Ongoing: Disability insurance evaluation

The Minimum Viable Month Exercise

Calculate the absolute minimum monthly expenses if everything went wrong.

Slash everything non-essential:

• Move to cheaper housing
• Eliminate all subscriptions
• Basic food only
• Minimum transportation

Sarah's example:

• Normal Survival Number: $2,405
• Crisis mode: $1,650 (shared housing, rice and beans, no car)

This number tells you how long your emergency funds actually last and identifies what's truly essential vs. "survival lifestyle."

Tools and Systems for Implementation

Essential Software and Apps

Banking and Money Movement:

• High-yield savings accounts for buffer and emergency funds
• Separate business checking for operating expenses
• Tax savings account with automatic transfers
• Accounting software (QuickBooks, FreshBooks, or Wave)

Income Tracking and Forecasting:

• Spreadsheet templates (Google Sheets or Excel)
• Project management tools (Asana, Notion) with financial tracking
• CRM systems for pipeline management
• Time tracking for hourly rate optimization

Budgeting and Planning:

• YNAB (You Need A Budget) - specifically designed for irregular income
• PocketSmith - good forecasting features
• Mint - free basic tracking
• Personal Capital - investment and net worth tracking

Spreadsheet Templates You Need

1. Income Tracking Sheet

• Monthly income for past 24 months
• Client-by-client breakdown
• Payment date vs. invoice date analysis
• Seasonal trend identification

2. Buffer Management Sheet

• Target buffer amount
• Monthly contributions/withdrawals
• Buffer health status
• Replenishment priorities

3. Cash Flow Forecast

• Known upcoming payments
• Expected project completions
• Seasonal adjustments
• Scenario planning (best/worst/likely case)

4. Tax Planning Worksheet

• Quarterly income tracking
• Tax set-aside calculations
• Deduction tracking
• Estimated payment planning

Automation Rules

Set up these automated transfers to make the system work without constant attention:

Every Client Payment:

1. 25-30% to tax savings account
2. Survival Number amount to checking
3. Remainder to buffer (up to target) or growth account

Monthly Automated Transfers:

1. Fixed expenses from checking account
2. Buffer adjustments as needed
3. Profit transfer to personal account (if using Profit First)

Quarterly Actions:

1. Tax payment from tax account
2. Buffer target reassessment
3. Profit distribution decision

Psychology of Irregular Income Management

Managing irregular income isn't just about math - it's about psychology.

The Feast Response Problem

What happens: Big payment arrives, you feel rich, spending increases Why it's dangerous: Creates lifestyle inflation that can't be sustained Solution: Immediately allocate the money before spending decisions

The 24-hour rule: When a large payment arrives, transfer money to designated accounts immediately. Wait 24 hours before making any discretionary spending decisions.

The Famine Response Problem

What happens: Low month hits, panic sets in, desperate decisions follow Why it's dangerous: Discounting rates, taking bad clients, poor boundaries Solution: Pre-decided responses to low-income months

Create a "Low Month Playbook":

• Specific business development actions
• Network activation checklist
• Rate protection strategies
• Spending reduction priorities

Identity and Self-Worth Issues

The problem: Irregular income can feel like irregular worth The mindset shift: Income variation is business economics, not personal value

Practical approaches:

• Track annual income trends, not monthly variations
• Celebrate business metrics beyond just revenue
• Separate personal identity from business cash flow
• Build confidence through skills development, not income consistency

Dealing with Family and Social Pressure

Common challenges:

• Family doesn't understand irregular income
• Social pressure to spend during high months
• Difficulty explaining financial decisions
• Imposter syndrome during low months

Communication strategies:

• Educate family about freelance income patterns
• Share annual numbers, not monthly swings
• Set boundaries around financial discussions
• Build support network of other freelancers

Long-Term Wealth Building with Irregular Income

Irregular income doesn't prevent wealth building - it just requires different strategies.

The Percentage vs. Dollar Amount Debate

Traditional advice: Save $X per month Irregular income reality: Save Y% of every payment

Example comparison: Fixed $500/month savings:

• High month ($6,000): 8.3% savings rate
• Low month ($1,200): 41.7% savings rate (impossible)

Fixed 15% savings rate:

• High month ($6,000): $900 saved
• Low month ($1,200): $180 saved
• Annual total: Same result, manageable execution

Investment Strategy for Variable Income

Emergency funds first: Always prioritize cash reserves before investing

Investment sequence:

1. Build and maintain buffer fund
2. Build emergency fund (6-12 months)
3. Max out tax-advantaged accounts (SEP-IRA, Solo 401k)
4. Taxable investment accounts
5. Alternative investments (real estate, etc.)

Dollar-cost averaging with irregular income:

• Set minimum monthly investment from low months
• Invest additional amounts from high months
• Maintain consistent investment habits

Retirement Planning Strategies

Use our Retirement Calculator to model different contribution strategies with irregular income.

SEP-IRA benefits for freelancers:

• Contribute up to 25% of income
• Flexible contributions (more in good years)
• Tax deductible
• Easy to set up and maintain

Solo 401(k) for higher earners:

• Contribute as employee AND employer
• Higher contribution limits
• Loan options
• More complex but more flexible

Backdoor Roth strategies:

• Convert traditional IRA to Roth in low-income years
• Tax diversification
• No required minimum distributions

Building Multiple Wealth Streams

Active income streams:

• Primary freelance services
• Retainer clients
• Consulting and coaching

Passive income development:

• Digital product sales
• Course and template sales
• Affiliate marketing
• Investment returns

Asset building:

• Business systems and processes
• Intellectual property
• Client relationships
• Personal brand and reputation

The goal: Reduce dependence on active work over time while building assets that generate income without direct time investment.

Common Mistakes and How to Avoid Them

Mistake 1: Using High Months to Justify Lifestyle Inflation

The trap: "I made $8K this month, I can afford a $200 monthly subscription" The problem: That subscription becomes a fixed cost even in $1K months The solution: Make spending decisions based on average income, not peak income

Rule of thumb: For any recurring expense, ask "Can I afford this in my worst month?" If no, wait until you've raised your income floor.

Mistake 2: Inadequate Tax Planning

The trap: "I'll deal with taxes at year-end" The problem: Quarterly penalties, cash flow crisis in April, no deduction planning The solution: Treat taxes as a monthly operating expense, not an annual event

System: Every payment → immediate tax transfer. No exceptions.

Mistake 3: Confusing Cash Flow with Profitability

The trap: "I have money in my account, so business is good" The problem: That money might be for taxes, next month's expenses, or client prepayments The solution: Use accounting software to track actual profit/loss by month

Key metrics to track:

• Cash flow vs. profit
• Effective hourly rate after expenses
• Client profitability analysis
• Monthly recurring revenue vs. project income

Mistake 4: Emergency Fund Neglect

The trap: "The buffer fund IS my emergency fund" The problem: Regular use erodes true emergency protection The solution: Separate funds with separate purposes

Clear definitions:

• Buffer fund: Regular monthly smoothing (3-4 months Survival Number)
• Emergency fund: True emergencies only (6-12 months Survival Number)

Mistake 5: Rate Pricing Without Income Fluctuation Consideration

The trap: Setting rates based on ideal scenarios The problem: Rates don't account for non-billable time, payment delays, project gaps The solution: Build fluctuation factors into your rate calculation

Use our Freelance Rate Calculator to factor in:

• Utilization rate (% of time actually billable)
• Payment delay averages
• Project gap time
• Seasonal variations

Example adjustment:

• Base hourly need: $50/hour
• Utilization rate: 60% (only 24 billable hours/week)
• Adjusted minimum rate: $50 ÷ 0.60 = $83/hour

Measuring Success with Irregular Income

Traditional metrics don't work well for irregular income. Here are better measures:

Financial Stability Metrics

Buffer Health Ratio: Current buffer ÷ Target buffer

• Target: 100% or higher
• Good: 75-100%
• Concerning: Below 75%

Income Volatility Coefficient: Standard deviation of monthly income ÷ Average monthly income

• Lower is better (less volatility)
• Track trends over time
• Compare year-over-year

Cash Runway: Emergency funds ÷ Monthly Survival Number

• Measures how long you could survive with zero income
• Target: 6-12 months minimum
• Review quarterly

Average Collection Period: Days between invoice sent and payment received

• Track by client
• Industry benchmarks vary
• Optimize for faster payments

Business Health Metrics

Monthly Recurring Revenue (MRR): Income from retainer clients and subscriptions

• More stable than project income
• Target: 50-70% of total income
• Build over time

Pipeline Value: Total value of potential projects × probability of closing

• Leading indicator of future income
• Track conversion rates
• Identify seasonal patterns

Effective Hourly Rate: Total income ÷ Total work hours (including admin, sales, etc.)

• More accurate than project-based rates
• Include all work time, not just billable
• Track monthly trends

Client Concentration Risk: Percentage of income from largest client

• Target: No single client over 50%
• Diversify over time
• Plan for client loss scenarios

Quality of Life Metrics

Financial Stress Days: Days per month worried about money

• Track in journal or app
• Good system should reduce this over time
• Identify triggers for stress

Income Prediction Accuracy: How well you forecast monthly income

• Track actual vs. predicted income
• Improve over time with better systems
• Reduce surprises

Lifestyle Consistency: Ability to maintain similar lifestyle regardless of income month

• The buffer system should enable this
• Track discretionary spending variation
• Aim for stability

Advanced Case Studies

Case Study 1: Sarah's Income Smoothing Success

Background: Graphic designer with income ranging from $900-$6,200 monthly

Challenge: Lifestyle whiplash, tax payment struggles, no savings

System Implementation:

• Survival Number: $2,405
• Buffer target: $8,418 (3.5 months)
• Tax percentage: 25%
• High month strategy: Buffer first, then lifestyle

Results after 18 months:

• Buffer consistently at target level
• Zero late tax payments
• $12,000 in true emergency savings
• 65% reduction in financial stress
• More selective with clients (better rates)

Key insight: "The buffer gave me the confidence to turn down low-paying rush jobs."

Case Study 2: Marcus's Multiple Stream Strategy

Background: Web developer with project income swinging $1,400-$18,400 monthly

Challenge: Boom-bust cycles, client concentration risk

Strategy:

• 40% project work (existing strength)
• 40% retainer clients (developed over 2 years)
• 20% product sales (courses and templates)

Implementation timeline:

• Year 1: Added first retainer client
• Year 1.5: Launched first digital product
• Year 2: 3 retainer clients, 2 products
• Year 2.5: 5 retainer clients, 4 products

Results:

• Income floor raised from $1,400 to $4,200
• Income ceiling remained high ($15,000+)
• Monthly variation reduced by 60%
• Working fewer total hours

Key insight: "Retainers eliminated the panic of project gaps. Products added upside without proportional work."

Case Study 3: Lisa's Seasonal Business Management

Background: Wedding photographer with severe seasonal income patterns

Monthly income pattern:

• Jan-Mar: $1,000-2,500 (editing season)
• Apr-Jun: $8,000-15,000 (peak season)
• Jul-Sep: $12,000-18,000 (peak season)
• Oct-Dec: $3,000-6,000 (slower season)

Strategy:

• Build massive buffer during peak season
• Develop off-season revenue streams
• Pre-pay annual expenses during high months

Buffer strategy:

• Target buffer: $15,000 (6 months survival)
• Peak season: Add $6,000-10,000 to buffer
• Off-season: Draw $3,000-5,000 from buffer

Off-season development:

• Portrait sessions
• Photography workshops
• Stock photo licensing
• Equipment rental

Results:

• Eliminated off-season financial stress
• Developed $2,000/month baseline off-season income
• Saved $45,000 for equipment and business expansion
• Took planned vacation during slow season

Key insight: "Planning for seasonality turned my weakness into a strength. I now prefer seasonal businesses."

Your 90-Day Implementation Plan

Days 1-30: Foundation Building

Week 1:

• Calculate your Survival Number
• Gather 12 months of income data
• Open separate savings accounts for buffer and taxes
• Set up basic income tracking spreadsheet

Week 2:

• Determine buffer target (3.5 × Survival Number)
• Calculate current buffer level
• Set up automatic tax transfers (25-30% of every payment)
• Create low-month playbook

Week 3:

• Implement four-bucket system for next payments
• Review and optimize current banking setup
• Start tracking daily expenses
• Identify income patterns and seasonality

Week 4:

• Build emergency fund target (separate from buffer)
• Set up basic forecasting system
• Review current tax situation and payments
• Create client payment term improvements plan

Days 31-60: System Optimization

Week 5-6:

• Refine Survival Number based on actual tracking
• Optimize payment collection processes
• Implement 12-week rolling average calculations
• Begin building retainer client pipeline

Week 7-8:

• Automate as many transfers as possible
• Create monthly review and planning routine
• Develop multiple income stream strategy
• Optimize tax withholding percentages

Days 61-90: Advanced Strategies

Week 9-10:

• Implement Profit First methodology
• Build 6-month income forecast
• Review and optimize rates using new cost understanding
• Develop business development metrics

Week 11-12:

• Create investment strategy for surplus funds
• Set up retirement account contributions
• Build client diversification plan
• Create annual financial planning calendar

Quarterly Reviews (Every 90 Days)

Financial system review:

• Buffer health and target adjustments
• Emergency fund adequacy
• Tax payment accuracy and timing
• Investment and retirement contributions

Business performance review:

• Income trends and seasonality
• Client concentration risks
• Rate optimization opportunities
• New income stream development

System optimization:

• Automation and process improvements
• Tool and software evaluation
• Forecasting accuracy improvements
• Stress reduction and lifestyle consistency

Conclusion: From Chaos to Control

Managing irregular freelance income isn't about eliminating the variability - it's about building systems that thrive with variability.

The transformation happens in stages:

Stage 1: Survival (Months 1-6)

• Stop the feast-or-famine emotional rollercoaster
• Build basic buffer and tax systems
• Establish Survival Number baseline

Stage 2: Stability (Months 7-18)

• Consistent monthly financial behavior
• Reduced money-related stress and decision fatigue
• Improved business decision making

Stage 3: Growth (Months 19+)

• Strategic use of high months for business investment
• Multiple income streams reducing volatility
• Wealth building acceleration

The compounding effect: Good financial systems enable better business decisions. When you're not desperate for next month's rent money, you can:

• Turn down bad clients
• Negotiate better payment terms
• Invest in business development
• Take calculated risks
• Build long-term relationships

Your irregular income becomes a competitive advantage because most freelancers never master it. You'll have the financial stability to be selective, strategic, and focused on growth rather than survival.

The feast-or-famine cycle doesn't have to control your life. With the right systems, irregular income becomes just another business variable you manage professionally.

Start with your Survival Number calculation today. Everything else builds from there.

Ready to optimize your freelance finances? Use our Freelance Rate Calculator to ensure your rates account for income irregularity, and check our Tax Calculator to set up proper tax withholding for variable income.