Quarterly Estimated Tax Calculator (2026)

How to use this quarterly estimated tax calculator

1. Enter the net profit you expect from self-employment across all of 2026. A best guess is fine; you can revise it at any quarter and adjust the remaining payments.
2. Add W-2 wages and the federal tax already withheld from them, if you have a job as well. Withholding counts towards your total, so it directly reduces what you owe in estimates.
3. Enter last year's total tax and AGI from your Form 1040. This is what unlocks the safe harbour, and it is the single most useful thing on this page.
4. Leave the QBI box ticked unless you know you do not qualify. Most sole proprietors under the income threshold do, and it materially lowers the bill.
5. Pay the safe-harbour figure if you would rather hold on to cash, or the full figure if you would rather owe nothing in April. Both are shown, and both are legitimate.

The safe harbour, and why the smaller number is often the right one

The IRS does not require you to predict your income correctly. It requires you to pay enough. You avoid an underpayment penalty if you pay at least 90% of what you end up owing for the year — or 100% of what you owed last year, whichever is smaller. If your prior-year AGI was above $150,000, that second figure rises to 110%.

This matters most in exactly the situation freelancers find themselves in: a year that is much better than the last one. If you owed $12,800 last year and expect to owe $20,840 this year, the safe harbour lets you pay $12,800 across the four quarters instead of $20,840. You still owe the difference at filing, but you keep roughly $8,000 in your own account for most of the year rather than the government's.

The trade is that the difference does not disappear. It arrives as a bill in April, and if you have spent it you are in a worse position than if you had simply overpaid. The safe harbour is a cash-flow tool for people who will actually keep the money aside, not a discount.

There is also a floor. If you expect to owe less than $1,000 after withholding, you do not need to make estimated payments at all. And if you have a W-2 job alongside your business, increasing withholding there is often simpler than making four separate payments — withholding is treated as paid evenly across the year regardless of when it actually happened, which is a useful property if you find yourself behind late in the year.

Example

A freelance web developer expects $95,000 in net profit for 2026, files as single, and has no W-2 job. Last year was slower: total tax of $12,800 on an AGI of $84,000. She qualifies for the QBI deduction.

Safe harbour: $3,200.00 per quarter. Full coverage: $5,210.06 per quarter.

The two safe-harbour tests give $18,756.22 (90% of this year) and $12,800.00 (100% of last year). She takes the smaller, so $12,800 across four quarters is $3,200.00 each — and the IRS charges no penalty even though she will end up owing $20,840.24.

The gap is $8,040.24, payable when she files. Paying the safe-harbour amount is a deliberate choice to hold that money until April rather than hand it over in instalments. It is only the right choice if it is still there in April.

Her prior-year AGI of $84,000 is below the $150,000 line, so the prior-year test is 100% rather than 110%. Had she earned more last year, the safe harbour would have been $14,080 instead of $12,800 — the high-income rule catches more people than expected, because it looks at last year, not this one.

The QBI deduction is doing real work here: $14,437.69 off taxable income, worth roughly $3,176 in tax at her 22% marginal rate. It applies to qualified business income and phases out above $201,775 for a single filer, with extra restrictions for service businesses at higher incomes.

Limits and things to watch for

• Federal only. State estimated taxes have their own rules, thresholds and dates, and several states do not follow the federal safe harbour at all.
• It assumes your income arrives evenly across the year. If it is lumpy — a large project in Q4, say — the annualised income instalment method on Form 2210 can reduce or eliminate a penalty that this flat approach would suggest.
• The QBI treatment is the simple case: under the income threshold, straightforward business income. Above the threshold, and for specified service businesses, the deduction phases out and depends on wages paid and property held.
• It does not handle tax credits, itemised deductions, capital gains rates, the alternative minimum tax, or retirement contributions — all of which change the answer, most of them downward.
• It is an estimate for planning, not a filing. Form 1040-ES is the actual worksheet.

Disclaimer. This calculator is general information, not tax advice. It uses published IRS and SSA figures for tax year 2026 and covers the ordinary case. Penalty rules, the annualised income method and state obligations depend on your circumstances. Confirm with a qualified accountant, and check the sources below if the last-updated date is old.

Frequently asked questions

What happens if I just do not pay quarterly?

You are charged an underpayment penalty, which is interest calculated per quarter on the amount you were short. It is not a flat fine and it is not catastrophic on small amounts — but it accrues from each missed date, so a year of nothing owed on a large bill adds up. You also arrive at April with the whole amount due at once, which is the part that actually hurts people.

Is the safe harbour really safe?

Yes, for the penalty. Paying 100% of last year's tax (110% if your prior-year AGI was over $150,000) protects you from an underpayment penalty no matter how much more you end up owing. What it does not do is reduce the tax — the balance is still due when you file.

When are the 2026 payments due?

April 15 and June 15 of 2026, September 15 of 2026, and January 15 of 2027. The last one catches people out every year because it falls in the following calendar year. If a date lands on a weekend or federal holiday it shifts to the next business day.

Can I pay more often than quarterly?

Yes. The IRS accepts payments at any time and many self-employed people pay monthly, or set aside a percentage of every invoice as it is paid. What matters for the penalty is that enough has been paid by each quarterly deadline, not how many payments it took.

I have a job as well — is there an easier way?

Increase your W-2 withholding instead, by filing a new W-4. Withholding is treated as having been paid evenly throughout the year no matter when it actually happened, so it can retroactively fix an underpayment that estimated payments cannot. It is often simpler than managing four separate transfers.

My income is very uneven. Does that change anything?

It can. The default assumption is even income across the year, so a big Q4 project makes it look like you underpaid in Q1 to Q3. Form 2210's annualised income instalment method lets you match payments to when the income actually arrived, and often removes the penalty entirely. It is more paperwork, and worth it when the amounts are large.

Related tools

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Guides

• Quarterly estimated taxes: dates, forms, penalties
• Self-employment tax explained (2026 rates)
• Freelance tax deductions checklist (2026)