Quarterly estimated tax calculator

For the self-employed, 1099 earners, and business owners: estimate what to send the IRS — and California's FTB — each quarter to stay penalty-safe under the §6654 safe harbor.

Filing status

Self-employment / business profit

Net profit subject to SE tax.

Other taxable income

W-2 wages, spouse income, interest, etc.

Tax already withheld (annual)

From any W-2 paychecks.

Children under 17

Prior-year total federal tax

Optional — enables the prior-year safe harbor.

Prior-year AGI was over $150,000 (uses the 110% safe harbor)

Include California estimated taxes

Estimated annual California tax

Use last year's CA tax (Form 540) as a safe-harbor estimate, or your projection.

Quarter	Due date (2026 tax year)	Federal	California

Want these dialed in so you never overpay or get penalized? Quarterly estimates are the heart of year-round tax planning — let's set yours.

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Estimate only, for planning — not tax advice. Federal figures use 2026 brackets, the standard deduction, and the $184,500 Social Security wage base (Rev. Proc. 2025-32); the federal estimate combines income tax and self-employment tax, less the child tax credit and any withholding. The §6654 safe harbor is the lesser of 90% of this year's tax or 100% of last year's (110% if prior-year AGI exceeded $150,000; $75,000 if married filing separately). California estimates apply your CA tax figure to the state's required 30% / 40% / 0% / 30% quarterly schedule — this tool does not compute California income tax from CA brackets. Not modeled: the Additional Medicare Tax, Net Investment Income Tax, AMT, the QBI deduction, itemized deductions, or California payroll/SDI items. California requires electronic payment once an estimate exceeds $20,000 or total tax exceeds $80,000, and filers with CA AGI of $1 million or more must use the 90%-of-current-year method. Confirm with a CPA before relying on these figures.