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IMAAR Associates CPA, PLLC

Free tax calculator

Quarterly estimated tax calculator

Project your federal tax for the year, subtract what will already be withheld, and split the rest across the four 1040-ES due dates — with the safe-harbor figures that protect you from a penalty.

Your year ahead

Nothing you type is collected, transmitted, or stored.

Tax year

Business or 1099 profit for the whole year, after expenses.

Wages, interest, dividends, rental income — anything taxed at ordinary rates.

From a W-2 job or pension. Withholding counts as paid evenly across the year.

Unlocks the prior-year safe harbor — often the safest target because it is a known number.

Optional. Adds a state line alongside your federal result.

Your estimated installments

Enter your expected income for the year to see your quarterly payments.

Projected federal tax and quarterly installments
Federal income tax—
Self-employment tax—
Total projected federal tax—
Less withholding—
Left to pay in installments—

Payment schedule

  • Q1 — due April 15 —
  • Q2 — due June 15 —
  • Q3 — due September 15 —
  • Q4 — due January 15 —

Safe harbor

90% of this year’s projected tax—

Federal only — state and local estimated payments have separate rules and dates. Assumes income arrives evenly through the year; if yours is seasonal, the annualised income installment method may serve you better. Excludes credits, the QBI deduction, and itemised deductions.

Estimate only — not tax advice. These figures are a general educational estimate based on federal tax data and the numbers you entered. They are not a tax return, not tax advice, and not a guarantee of your actual tax. They exclude many credits, deductions, phase-outs, state and local taxes, and situation-specific rules. Using this tool does not create a client relationship. For numbers you can rely on, book a free consultation.

Get your payments reviewed

How this works

Paying tax before the year has finished

The U.S. federal tax system is pay-as-you-go. For employees that is invisible — withholding takes a slice of every paycheck automatically. The moment income arrives without withholding, that machinery stops, and the obligation to pay through the year becomes yours to manage.

Estimated payments are how that is done. Four times a year you send the IRS a payment against the tax you expect to owe, using Form 1040-ES. For a calendar-year filer the deadlines fall in April, June, September, and the following January. Note that they are not evenly spaced — the second installment comes just two months after the first, which catches out people budgeting on a strict quarterly rhythm.

The hard part is that you are paying tax on a year that has not happened yet. This is where the safe harbor earns its keep. Rather than trying to forecast perfectly, you can pay a defined amount and be protected from an underpayment penalty even if your actual tax lands higher. Pay 90% of what you end up owing this year, or 100% of what you owed last year, and you are inside the harbor. If your prior-year adjusted gross income was above $150,000, that second test rises to 110%.

Most people with volatile income aim at the prior-year figure for exactly one reason: it is certain. Last year’s tax is a number on a filed return, not a forecast. If this year turns out bigger, you settle the difference in April without penalty. If it turns out smaller, you have simply paid ahead.

One asymmetry is worth knowing. Estimated payments count when you make them, but withholding is treated as spread evenly across the whole year regardless of when it happened. So if you reach November and realise you are short, increasing withholding on a W-2 job — yours or a spouse’s — can repair the whole year in a way a late estimated payment cannot.

To project the underlying tax first, use the self-employment tax calculator. For a return prepared and reviewed by a CPA, see tax preparation or book a free consultation. Most states run their own state estimated taxes on separate schedules — choose your state above to see the annual state figure alongside the federal one.

Questions

Estimated tax, answered

Broadly, anyone with income that has no withholding — freelancers, contractors, business owners, landlords, and people with significant investment income. The federal system is pay-as-you-go: the IRS expects tax on income in the quarter you earn it, not in a single payment the following April.

The safe harbor is the amount you can pay to avoid an underpayment penalty even if your final tax turns out higher. Generally you are protected if you pay at least 90% of the current year’s tax, or 100% of last year’s tax (110% if your prior-year adjusted gross income was over $150,000). Paying to the prior-year figure is popular precisely because it is a known number — you are not guessing at a year that has not finished.

For a calendar-year filer the federal installments are due 15 April, 15 June, 15 September, and 15 January of the following year. When a date falls on a weekend or holiday it shifts to the next business day.

Splitting the year into four equal payments assumes income arrives evenly. If yours is seasonal or lumpy, the annualised income installment method on Form 2210 can reduce or remove a penalty by matching payments to when income was actually earned. It is more work, and worth advice.

Yes, and helpfully so — withholding is treated as paid evenly across the year no matter when it happened. If you or a spouse also have a W-2 job, increasing withholding late in the year can fix an underpayment that estimated payments alone could not.

State and local estimated payments, which have their own rules and dates; credits; the qualified business income deduction; itemised deductions; and the annualised income method. It assumes the standard deduction and an even split.

Not sure which safe harbor to aim at?

Book a free consultation and get an answer you can act on — no obligation.

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Important disclaimer Read

This calculator is provided for general educational and informational purposes only. It is not tax, legal, accounting, or financial advice, and must not be relied upon as such.

No professional relationship. Using this calculator does not create a CPA-client, advisory, or any professional relationship between you and IMAAR Associates CPA, PLLC. A professional relationship is established only through a signed engagement letter.

Estimates only; no warranty of accuracy. Results are approximations based solely on the limited information you enter and on general federal tax figures for the selected year (sources: IRS Rev. Proc. 2024-40 for 2025 and Rev. Proc. 2025-32 for 2026). Tax law is complex and changes frequently. The calculator does not account for all credits, deductions, phase-outs, alternative minimum tax, the qualified business income (QBI) deduction, net investment income tax, state or local taxes, or facts specific to your situation. IMAAR Associates CPA, PLLC makes no representation or warranty, express or implied, as to the accuracy, completeness, or applicability of any result.

No reliance; hold harmless. You should not make any financial, tax, or business decision based on this calculator alone. Any reliance you place on it is strictly at your own risk. To the fullest extent permitted by law, IMAAR Associates CPA, PLLC disclaims all liability for any loss or consequence arising from use of this tool.

For advice you can rely on, book a free consultation with a Washington State Licensed CPA.

Figures: IRS Rev. Proc. 2024-40 (2025) and 2025-32 (2026). Federal figures only — state and local taxes are not included. All calculations run in your browser. Nothing you enter is collected, transmitted, or stored.

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