How to use the number
The set-aside figure is your estimated federal (plus optional flat state) tax for the year at that profit level. The habit that works: every time a payout lands, move the set-aside share to a separate savings account, then pay quarterly from that account on the 2026 deadlines. The calculator's per-quarter line sizes those payments; if you paid tax last year, the prior-year safe harbor can lawfully lower what you must prepay.
What this calculator deliberately doesn't do
It models federal self-employment and income tax with the standard deduction and the QBI deduction, plus an optional flat state rate. It does not model itemized deductions, credits, W-2 wage interplay, state brackets, or local taxes. Those aren't rounding errors for some situations, which is one reason the number is an estimate and not advice.
Sero gives you estimates to help you organize your finances and set money aside for taxes. Sero is not a tax preparer, accountant, or financial advisor, and nothing in the app is tax, legal, or financial advice. Estimates are based only on the information you enter and may not reflect your complete tax situation. Always confirm with a qualified professional before filing or making financial decisions. Sero does not file returns and does not move your money.