A cash-flow workflow for independent work

Plan the reserve before the 1099 payment arrives.

A gross-receipts percentage is easy to repeat and easy to get wrong. TaxMathKit separates business profit, self-employment tax, federal income tax and withholding, then converts the remaining planning amount into a quarterly target and a suggested transfer from a typical payment.

Start with a worked example

Your 1099 cash-flow estimate

Change only the inputs you know. State tax, credits and exact safe-harbor rules remain explicit follow-up checks.

Your inputs
Enter the details you haveEnter the payments you received and your business costs. We calculate profit, federal income tax, self-employment tax and a reserve amount automatically.
Add W-2 wages, withholding, payment size or QBIOptional
Estimated result
Estimated total federal tax$16,064
Net 1099 profit$72,000
Self-employment tax$10,173
Federal income tax$5,891
Remaining after withholding$16,064
Simple quarterly reserve$4,016
Suggested reserve from typical payment$267.74
Reserve rate on 1099 receipts17.8%

Simplified 2026 federal estimate. State tax and many credits, phaseouts and deductions are not included.

Inputs stay in this browser and are never uploaded.
01

Use profit, not the invoice total

Start with revenue and ordinary business expenses. The reserve rate is shown against 1099 receipts so each payment can be handled consistently, while the tax estimate itself is built from profit.

02

Keep withholding in the picture

W-2 withholding reduces the amount still to plan for. Enter it instead of treating a second job as unrelated income.

03

Turn the estimate into a habit

Use the suggested reserve from a typical payment as a transfer target, then compare it with the quarterly installment and your actual year-to-date numbers.

Questions this workflow answers

Find the situation that matches your income.

Method and boundaries

A planning estimate is not a payment voucher.

The result is a transparent federal planning estimate based on the selected filing status, 2026 brackets, self-employment tax mechanics and entered withholding. Check current IRS instructions, prior-year safe-harbor rules, state obligations, local taxes, credits, retirement contributions and business-specific deductions before filing or paying.

Read the calculation methodology →