TabSalary calculator guide
Estimate a side-hustle tax set-aside
Independent workers usually do not have an employer withholding income and self-employment taxes from each payment. This planning tool applies a selected effective rate after a mileage deduction to suggest how much cash to reserve. It is intentionally simpler than a tax return.
Independently built and maintained · Published July 23, 2026 · Last reviewed August 23, 2026
Gig platforms pay gross: the $150 from a day of deliveries arrives with nothing withheld, while the tax bill on that money arrives next spring. New freelancers discover this at filing time and end up scrambling to cover both income tax and self-employment tax on money already spent. Reserving a percentage the moment income lands converts one painful April surprise into a routine transfer.
The calculator models the two adjustments that matter most for small gig operations: the business-mileage deduction, which shields part of your earnings using the IRS standard mileage rates, and an effective-rate selector that reflects where your combined income-plus-SE-tax exposure likely sits. It is deliberately not a tax engine — it is a reserve discipline tool with current-year rates built in.
How the calculation works
Estimated reserve = max(0, gross earnings − business miles × selected period mileage rate) × selected effective rate
- Enter gross business income received or earned for the period you are planning.
- Choose the 2026 mileage period, then enter documented eligible business miles; the tool applies 72.5¢ for January–June or 76¢ for July–December.
- Choose a rough effective tax rate that reflects income tax plus self-employment tax exposure.
- Move the estimated reserve to a separate savings account and reconcile it against quarterly estimates.
Worked example
For $150 of gross earnings and 40 qualifying business miles after June 30, 2026, the mileage estimate is $30.40. The remaining $119.60 multiplied by a 25% planning rate suggests reserving $29.90. Actual deductible mileage and tax depend on eligibility, records, total annual income, filing status, state law, and other expenses.
What this estimate does not include
- This is not a tax return and does not calculate brackets, credits, quarterly safe-harbor rules, state taxes, or the deductible portion of self-employment tax.
- The 76¢ rate applies to eligible business mileage from July 1 through December 31, 2026; earlier 2026 mileage uses 72.5¢.
- Commuting is generally not deductible business mileage. Keep contemporaneous records and consult a qualified tax professional for your circumstances.
Use the result as a planning estimate, not as personalized financial, tax, legal, or investment advice.
Source ledger
Primary references- Internal Revenue Service: standard mileage rates — 76¢ per business mile for July 1–December 31, 2026 (IR-2026-29) and 72.5¢ for January 1–June 30, 2026 (IR-2025-128).
- Internal Revenue Service Publication 463: Travel, Gift, and Car Expenses — business transportation, commuting rules, and recordkeeping requirements.
Rates and rules are checked against the primary source before publication and re-checked whenever the source changes. External links open in a new tab; calculator inputs never leave your browser.