Quarterly Tax Calculator 2026

What estimated tax actually covers

Estimated tax is the income that reaches you without anybody withholding from it: self-employment profit, rental income, interest and dividends, capital gains, and a working spouse's wages when the combined W-4 does not hold enough. Two taxes ride on that money:

federal income tax    your brackets on taxable income, after the standard deduction
self-employment tax   15.3% on 92.35% of net profit (Social Security + Medicare)
                      when you work for yourself, nobody pays the employer half

FICA is deliberately not in this number. If you are an employee, 7.65% already comes out of every paycheck, and there is nothing to estimate. Only the income tax and — if you have profit — the self-employment tax belong here.

This calculator runs the 2026 federal brackets and the self-employment rules through the same engine behind our income tax calculator, so the quarterly figures and the annual figures can never disagree. State estimated payments are a separate set of rules in most states and are shown here as a reference line only.

The two safe harbors, side by side

You do not have to pay 100% of a moving target. The IRS accepts either of two numbers, and you are allowed to use the smaller:

Last year's number is lower here, so $11,000 is the target. That is the whole point of entering last year's total tax: in a year when your income grows, the prior-year rule lets you defer part of the increase to April without a penalty.

Three filers, three very different quarters

The second row flips to the 90% rule because income fell, the third has no prior-year figure to compare against. The right-hand column is not a mistake — paying the safe harbor means you deliberately leave a balance for April.

Paying the minimum is a choice, not a loophole

Paying $2,750 a quarter instead of $3,247.27 keeps $1,989 in your pocket for another four months. Whether that is worth it depends on what happens next April:

• If income comes in unevenly. A Q4-heavy year means the equal-quarter assumption is wrong. Form 2210 Schedule AI lets you annualize and pay by when the money actually arrived, which can cut the required payment substantially.
• If your profit is still climbing. The prior-year safe harbor is generous precisely when you earn more; the catch is that next April you owe the gap in one check.
• If you can raise withholding instead. A wage-earning spouse can bump their W-4, and withholding is treated as paid evenly through the year no matter when it comes out. That is the cleanest way to cover a shortfall.
• If the gap is large. The underpayment penalty is interest on the shortfall, computed per quarter on Form 2210 — it is not a flat fine, and it stops accruing once you pay.

Four dates that are not evenly spaced

The quarters are uneven because the tax year does not divide into four equal blocks: Q1 ends March 31 and is due April 15 (roughly two weeks of grace), while Q2 covers only two months and Q3 covers three. Q4 is due January 15 of the following year, after the tax year has already closed.

If a due date falls on a weekend or holiday it moves to the next business day. If you file your return and pay the whole balance by January 31, the Q4 payment is unnecessary.

How to use this calculator

1. Enter your net profit for the year — gross receipts minus deductible expenses, the number that lands on Schedule C line 31.
2. Add any W-2 wages in the household and the federal tax those employers will withhold.
3. Choose your filing status and state. Nine states levy no wage income tax; in the rest, treat the state line as a reminder that a state estimate may also be due.
4. Enter the total tax from last year's return (1040 line 24) to unlock the prior-year rule, and tick the box if last year's AGI was over $150,000.
5. Read the quarterly figure, then the balance next April — they are two sides of one decision.

Frequently asked questions

How much should I pay each quarter?

Pay the smaller of 90% of this year's tax and 100% of last year's tax (110% if last year's AGI exceeded $150,000), minus whatever your employer withholds, then divide by four. In the $60,000 profit example that is $11,000 a year, or $2,750 a quarter.

What happens if I pay nothing?

You owe the tax anyway, plus interest on the underpayment computed per quarter on Form 2210. The penalty accrues from the date each installment was due, so a payment made in December does not retroactively fix an April shortfall.

Do I need to pay estimated tax if I have a W-2 job?

Only if your withholding will not cover the bill. Raise your W-4 instead of writing checks whenever you can: withholding is treated as paid evenly across the year regardless of when it actually comes out of your paycheck, which is more forgiving than quarterly installments.

Is the underpayment penalty a fixed percentage?

No. It is interest on the amount you should have paid, calculated separately for each period, at a rate the IRS sets quarterly. Because the rate changes during the year, this calculator shows the shortfall but not a penalty dollar figure.

Can I just pay more in Q4 to catch up?

Not fully. Estimated tax is period-based, so a late catch-up reduces the penalty only for the period in which you pay. Raising withholding is the exception — W-2 withholding is treated as even throughout the year no matter when it is taken out.

Do states require estimated payments too?

Most states with an income tax do, and their thresholds, due dates and safe-harbor percentages differ from the federal rules. This page computes the federal figure; your state's Department of Revenue sets its own requirements.

Data sources: Federal brackets, the standard deduction and the self-employment tax rules follow IRS guidance for tax year 2026 (returns filed in 2027): 15.3% on 92.35% of net profit, with half of it deductible. The safe-harbor thresholds (90% of the current year, 100% or 110% of the prior year, and the $1,000 floor) come from the IRS estimated tax rules for individuals. State rates are prefilled only where verified against a state Department of Revenue; nine states have no wage income tax. Every figure is computed in your browser — nothing you type leaves the page. For the annual view see the tax calculator; if you are owed money instead, use the tax refund calculator.