Quarterly Tax Calculator

Enter your expected self-employment profit for 2026 and this calculator returns your IRS estimated tax payment per quarter — self-employment tax plus federal income tax — along with the safe-harbor minimum that protects you from underpayment penalties and the four due dates.

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How IRS estimated tax payments work

The US tax system is pay-as-you-go: employees pay all year through withholding, and everyone else — freelancers, 1099 contractors, side-hustlers, landlords, FBA sellers — is expected to send the IRS money four times a year instead. The trigger is simple: if you expect to owe $1,000 or more after subtracting any withholding, the IRS wants estimated payments (Form 1040-ES). Below $1,000, you can simply settle up when you file.

What you're prepaying is two taxes stacked together: self-employment tax — both halves of Social Security and Medicare, since no employer is splitting it with you — and ordinary federal income tax on your profit. This calculator computes both with the verified tax year 2026 figures (IRS Rev. Proc. 2025-32 brackets and standard deductions; $184,500 Social Security wage base per the Social Security Administration), then divides what withholding doesn't cover by four.

The formula

SE tax = Profit × 0.9235 × 15.3%
Income tax = 2026 brackets applied to (Profit − ½ SE tax + other income − standard deduction)
Quarterly payment = (SE tax + Income tax − withholding) ÷ 4

Profit is self-employment income minus business expenses (Schedule C). The 0.9235 factor exists because you pay SE tax on 92.35% of profit — mirroring how employees don't pay FICA on their employer's share. The 15.3% is 12.4% Social Security (2026 cap: the first $184,500 of net earnings) plus 2.9% Medicare (no cap). Half the SE tax is deductible before income tax is figured, and the standard deduction ($16,100 single / $32,200 married / $24,150 head of household for 2026) comes off too.

Worked example

A single freelancer expects $80,000 of 2026 profit and has no other income. Net earnings: $80,000 × 0.9235 = $73,880. SE tax: $73,880 × 15.3% = $11,303.64.

Taxable income: $80,000 − $5,651.82 (half the SE tax) − $16,100 standard deduction = $58,248.18. Income tax on that through the 2026 brackets: $7,526.60. Total federal tax: $18,830.24 — so the estimated payment is $4,707.56 per quarter. (If last year's total tax was only $12,000, the safe harbor drops the required payment to $3,000 per quarter — read on.)

The safe harbor rule — the most valuable thing on this page

Most freelancers don't know this, and it's worth real money: you don't have to guess this year's income correctly to avoid penalties. Under the IRS safe-harbor rules (Form 1040-ES / IRC §6654), no underpayment penalty applies as long as your withholding plus estimated payments reach the smaller of:

90% of this year's taxthe "keep up with reality" target
100% of last year's total tax110% if your 2025 AGI was over $150,000 ($75,000 married filing separately)

The second line is the gem. Had a modest 2025 but 2026 is taking off? Pay 100% of last year's tax in four even installments and you are penalty-proof — even if you end up owing five times that in April. You'll still owe the balance when you file, but at 0% penalty, which means you can hold the difference in savings instead of lending it to the Treasury early. This is why the calculator asks for last year's total tax: when the safe-harbor number is lower than the straight quarter of this year's estimate, it shows you both.

The 2026 due dates (and their weird spacing)

For tax year 2026 the payments are due April 15, 2026 (Wednesday), June 15, 2026 (Monday), September 15, 2026 (Tuesday), and January 15, 2027 (Friday) — all business days, so no weekend shifts this cycle (per Form 1040-ES; when a date does hit a weekend or holiday, it slides to the next business day). Notice they aren't real quarters: the "Q2" payment lands just two months after Q1, covering April–May only, and the final payment arrives in the following calendar year. Many freelancers get tripped up by June, not April.

What happens if you miss one

The penalty is interest in a costume, not a fine: the federal short-term rate plus 3 points — 7% annualized as of Q3 2026, per the IRS quarterly interest rate announcements (it was 6% in Q2 2026, and it resets every quarter) — charged from each due date on that installment's shortfall, computed on Form 2210. Missing a $3,000 payment by two months costs roughly $35, so don't panic — but don't coast either, because each quarter's shortfall keeps accruing until paid. Two quirks worth knowing: you can't repair a missed Q1 by overpaying Q4, since each installment is scored separately; but withholding is treated as paid evenly through the year, so cranking up a W-2 job's withholding in December can retroactively fix all four quarters. That asymmetry is the single best year-end rescue trick in the estimated-tax game.

How to actually pay

Skip the paper vouchers. IRS Direct Pay pulls from your bank account free, no enrollment, in about two minutes — pick "Estimated Tax" and "1040-ES." EFTPS (the Treasury's payment system) requires enrollment but lets you schedule all four payments a year ahead, which is the closest thing to autopilot the IRS offers. Your IRS Online Account also shows a running history of what you've paid — worth checking before you file, since a forgotten June payment is the classic cause of a "why is my refund wrong" spring.

The half-of-SE-tax quirk

Two adjustments make SE tax gentler than the sticker 15.3%, and this calculator applies both. You pay SE tax on only 92.35% of profit, and you deduct half the SE tax before figuring income tax — the analog of an employer's FICA share being invisible to employees. Net effect: the true SE tax burden is about 14.1% of profit, and the half-tax deduction saves income tax on top (the $80,000 freelancer above deducts $5,651.82, worth about $1,243 at a 22% marginal rate). When comparing a W-2 offer against contract work, remember the employee comparison isn't 0% vs 15.3% — the employee already loses 7.65% to FICA; the self-employed premium is the other, softened half. And if your freelance year includes selling appreciated assets, capital gains ride on top of all this — the capital gains tax calculator covers that layer, and the income tax calculator handles the W-2 side of a mixed year.

Frequently asked questions

How do I calculate quarterly taxes for a side hustle?

Take your expected net profit (income minus business expenses), multiply by 92.35% and then 15.3% to get self-employment tax, add federal income tax on your total taxable income at your bracket rates, subtract whatever your day job already withholds, and divide by four. That's exactly what this calculator does with the 2026 figures. Quick rule of thumb while you wait for the math: set aside 25–30% of every side-hustle dollar.

What are the estimated tax due dates for 2026?

For tax year 2026 the four payments are due April 15, 2026; June 15, 2026; September 15, 2026; and January 15, 2027 — all regular weekdays, so no weekend shifts this cycle. Note the uneven spacing: the second 'quarter' covers only April and May. If a due date ever falls on a weekend or holiday, it moves to the next business day.

What is the safe harbor rule for estimated taxes?

The IRS won't charge an underpayment penalty if your withholding plus estimated payments reach the smaller of two targets: 90% of this year's tax, or 100% of last year's total tax (110% if your prior-year AGI was over $150,000). The second target is the gold one for freelancers with growing income — pay 100% of last year's tax in four even installments and you're penalty-proof no matter how good this year turns out to be.

What happens if I miss a quarterly payment?

The IRS charges an underpayment penalty that works like interest — the federal short-term rate plus 3 points, which is 7% annualized as of the third quarter of 2026 — computed per quarter on Form 2210 from the day the payment was due. It's not a cliff: missing by a month on one payment costs a few dollars per thousand. Pay as soon as you notice, because a late Q1 can't be fixed by overpaying Q4 — except through withholding, which the IRS treats as paid evenly all year.

Do I need to make estimated payments if I also have a W-2 job?

Only if your day-job withholding won't cover the safe harbor. You expect to owe less than $1,000 after withholding? No estimated payments required at all. And there's a cleaner fix than quarterly payments: file a new W-4 and have your employer withhold extra. Withholding is treated as paid evenly through the year, so even a December withholding boost can retroactively cover the whole year — a trick estimated payments can't do.

How much should I set aside for taxes as a 1099 contractor?

A useful default is 25–30% of net profit for federal taxes at moderate incomes — roughly 14% effective self-employment tax plus your income tax bracket — and more like 35–40% once you're well into the 22–24% brackets or live in a state with income tax. Run your real numbers above rather than trusting the rule of thumb: the answer swings a lot depending on filing status, other income, and deductions.

What is the self-employment tax rate for 2026?

15.3% of net earnings (which the IRS defines as 92.35% of your net profit): 12.4% for Social Security on earnings up to the $184,500 wage base for 2026, plus 2.9% for Medicare with no cap. High earners owe an extra 0.9% Additional Medicare Tax above $200,000 ($250,000 married filing jointly). You do get to deduct half of your SE tax when computing income tax — a consolation prize this calculator applies automatically.

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