Income Smoothing
Convert irregular or variable income into a stable monthly salary. Enter 6 months of income to calculate a safe baseline and required buffer fund.
About this calculator
Freelance and gig income rarely arrives in equal amounts, so this calculator converts six months of actual, or projected, income into a conservative monthly salary you can budget against. Rather than using a straight average, it takes your three lowest-earning months out of the six and averages just those — a deliberately cautious approach that ensures the "salary" you pay yourself is a number your worst realistic months can actually sustain, not one that assumes every month looks like your best ones. The gap between that smoothed salary and your true six-month average becomes your monthly buffer contribution: the surplus from good months that needs to be set aside rather than spent, so it's available to cover the difference in lean months.
If your smoothed salary alone can't cover your fixed expenses, the calculator instead sizes the buffer fund around that shortfall directly — three months of the gap between expenses and smoothed income — since covering fixed costs takes priority over smoothing further. Dividing the buffer target by your monthly contribution rate gives a rough timeline for building the fund. The three-lowest-months method is intentionally conservative and works best with a full income history; six months of data from a brand-new freelance business may not yet capture a slow season that hasn't happened, so treat the smoothed number as a floor to revisit periodically rather than a permanent fixed salary.
Financial Disclaimer
This calculator is for educational purposes only and does not constitute financial advice. Results are estimates based on the inputs provided. Consult a qualified financial advisor before making investment or financial planning decisions.
Inputs
Results
Smoothed Salary (Conservative)
$4,000.00
≈ 4 smartphones
Buffer Fund Target
$3,000.00
≈ 3 smartphones
How to Use This Calculator
- Enter your actual income for each of the last 6 months (or projected months for new freelancers).
- Input your monthly fixed expenses so the calculator can determine your income floor.
- Review Average Monthly Income and Smoothed Salary (Conservative) — pay yourself this amount each month regardless of income.
- Check Monthly Buffer Contribution and Buffer Fund Target to plan how much to save for lean months.
- Use Months to Buffer to set a timeline for building your income-smoothing fund.
How the result changes with Month 5 Income
| Month 5 Income | Smoothed Salary (Conservative) | Buffer Fund Target |
|---|---|---|
| $2,250.00 | $3,250.00 | $4,125.00 |
| $3,375.00 | $3,625.00 | $3,562.50 |
| $6,750.00 | $4,166.67 | $3,624.99 |
| $11,250.00 | $4,166.67 | $5,874.99 |
What each input means
- Month 1 Income
- Income received in month 1
- Month 2 Income
- Income received in month 2
- Month 3 Income
- Income received in month 3
- Month 4 Income
- Income received in month 4
- Month 5 Income
- Income received in month 5
- Month 6 Income
- Income received in month 6
- Monthly Fixed Expenses
- Total monthly bills and fixed expenses you must cover
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersMonth 1 Income = 4000, Month 2 Income = 6000, Month 3 Income = 3500, Month 4 Income = 7000 = 7 input(s) provided
- Calculate Smoothed SalarySmoothed Salary4000 = $4,000
- Calculate Buffer Fund Target3000 = $3,000
- Calculate Average Monthly IncomeAverage Monthly Income5000 = $5,000
- Calculate Monthly Buffer ContributionMonthly Buffer Contribution = max(monthlyBufferContribution1000 = $1,000
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does the calculator use the average of the three lowest months instead of a simple 6-month average?
It sorts all six months and averages the bottom three specifically to build a salary you can sustain even in a bad stretch, rather than one that assumes typical months look like your best ones. A straight average would overstate what you can safely pay yourself in the months your income actually comes in low.
How is the Monthly Buffer Contribution different from the Buffer Fund Target?
Monthly Buffer Contribution is the gap between your true 6-month average income and your conservative smoothed salary — the surplus generated in good months that needs to be set aside rather than spent. Buffer Fund Target is the total amount you're aiming to accumulate; when your smoothed salary can't cover fixed expenses it's sized around that shortfall over three months instead, since covering fixed costs takes priority over further smoothing.
What happens if my smoothed salary is lower than my fixed expenses?
The calculator switches its buffer-sizing logic: instead of targeting three months of the surplus between your average and smoothed income, it targets three months of the shortfall between your fixed expenses and your smoothed salary. That reflects the fact that in this case your immediate problem is covering bills, not smoothing further surplus.
Why does Months to Build Buffer sometimes show 0?
That happens when your Monthly Buffer Contribution is zero or negative — meaning your six-month average isn't actually higher than your smoothed (lowest-three-month) salary, so there's no monthly surplus flowing into the buffer fund under this model. In that case you'd need to either increase income, reduce the smoothed salary further, or find savings elsewhere to build a cushion.
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