Quarterly estimated tax calculator

A single filer with $100,000 of net 1099 profit and no other income owes about $22,365 in federal tax for 2026. Paying 90% of that means $5,032 on each of four due dates. If last year’s total tax was $9,500, the safe harbor drops each payment to $2,375 and leaves $12,865 due when you file. Both approaches avoid the underpayment penalty. The next due date is Friday, January 15, 2027.

This calculator builds the whole payment plan. It computes your 2026 tax with the same engine as the 1099 tax calculator, picks the lower of the safe-harbor tests, splits the result across the four due dates, supports the annualized income method for lumpy earnings, and estimates the penalty if you have already missed or shorted a payment.

Who reaches for this

The estimate is a chain of six steps. Each one feeds the next, and you can override any of them by leaving a field blank or changing an input.

The tax itself uses the mechanics explained on the 1099 page: net profit, self-employment tax at 14.13% of profit, the half-SE deduction, the QBI cap, and brackets. If you want to see that computation line by line before splitting it into payments, start with the 1099 tax calculator. For the self-employment tax rules on their own, use the self-employment tax calculator.

Federal estimated payments are due on the 15th of April, June, September and January. When the 15th lands on a weekend or a legal holiday, the deadline moves to the next business day. Here are the verified dates for the current tax year and the next one, with the weekday each falls on.

Two dates deserve a second look. Several published guides list June 16 for the 2026 second payment. June 15, 2026 is a Monday, so the deadline does not move. A few list January 18, 2027 for the fourth payment, but January 15, 2027 is a Friday. The one date that does shift is the 2027 tax year’s fourth payment: January 15, 2028 falls on a Saturday and Monday, January 17 is Martin Luther King Jr. Day, so the deadline becomes Tuesday, January 18, 2028.

The four periods are not equal. April 1 through May 31 is only two months, so the June 15 payment arrives about ten weeks after the April one. That surprises people who assume quarters are calendar quarters. It also means a freelancer who earns heavily in March owes for it in April, while one who earns heavily in December does not owe for it until the following January.

If you pay electronically, choose a payment date on or before the due date and keep the confirmation number. State due dates are separate and sometimes different, which the state section covers.

You generally must make estimated payments for 2026 if both of these are true. You expect to owe at least $1,000 in tax after subtracting withholding and refundable credits. And you expect your withholding and credits to be less than the smaller of 90% of this year’s tax and 100% of last year’s tax. The prior-year number becomes 110% when last year’s adjusted gross income was above $150,000, or above $75,000 if you are married filing separately.

That covers freelancers, sole proprietors, partners and S corporation shareholders, and also landlords, investors with large gains, and retirees whose pension or IRA withholding is too low. The rule does not care what kind of income it is. It cares whether enough tax will have been paid by each date.

Four exceptions that matter

First, the $1,000 floor. If you expect to owe less than $1,000 after withholding, no payments are required. The tax is still due at filing. Second, the zero-tax exception. If you owed no tax last year, were a U.S. citizen or resident for the whole year, and last year’s return covered 12 months, you owe no estimated payments this year no matter how much you earn. That is unusual, but it applies to some people who were students or between jobs last year.

Third, the 12-month condition on the prior-year test. If last year was a short tax year, the 100% and 110% safe harbors are not available and you are left with the 90% test or the annualized method. Fourth, farmers and fishers. If at least two-thirds of your gross income in the current or prior year came from farming or fishing, the current-year test drops to 66⅔%, and you can pay everything in one installment on January 15 instead of four.

Your first year of self-employment

Some guides tell first-year freelancers that no prior-year safe harbor exists. That is only true if you did not file a return last year. If you were an employee last year and filed a full-year return, that return’s total tax is your prior-year benchmark, and it is often far below this year’s tax. A W-2 worker who owed $6,000 last year and expects $12,000 of tax this year with the new side income can be penalty-free by paying $6,000 in total through withholding and estimated payments. The catch is the April balance, which will be large. Set the difference aside.

The required annual payment is the smaller of two numbers, so the rule that protects you depends on how your income moved. The table uses one fixed this-year situation, $100,000 of profit and $22,365 of tax, and changes what happened last year. The last-year tax figures are hypothetical.

Read the table by row. When income is flat, 90% of this year’s tax is the lower number, so it governs. Last year’s figure protects you only when this year is bigger. When income has fallen, last year’s tax, even at 110%, is high, and the current-year test is the sensible one. Paying 110% of a bigger prior-year number would mean lending the IRS about $38,600 more than the safe harbor needs. With no prior return, the 90% test is the only fixed target.

The second row is the important one for growing freelancers. The prior-year rule cuts each payment from $5,032 to $3,475, which frees $6,228 of cash across the year, but it leaves $8,465 due in April. Both choices avoid the penalty. They differ in when you hand over the money. If you can reliably park the difference in a separate account, the prior-year method costs you nothing. If the temptation to spend it is strong, the 90% method forces the discipline.

One more point that tends to get lost. Meeting a safe harbor removes the penalty. It does not reduce the tax. In the second row you still owe $22,365 for the year. The safe harbor only decides when it is due without extra interest.

Equal installments assume you earn profit evenly. If you earn most of it late, you would be paying early for money that has not arrived, and the regular method can still charge a penalty on the early installments if you paid less. The annualized income installment method fixes that by tying each payment to profit actually earned by the end of each period.

The method scales year-to-date profit up to a full year using factors of 4, 2.4, 1.5 and 1, computes tax on that annualized figure, and multiplies by 22.5%, 45%, 67.5% and 90%. The requirement at each due date is the smaller of that number and the regular installment. Here is a freelancer whose $100,000 of profit is back-loaded because clients pay late in the year.

The tax on the annualized profits is $3,025, $4,923, $8,580 and $22,365. Multiplied by 22.5%, 45%, 67.5% and 90%, they give the cumulative amounts above. The installments are the differences: $681, $1,534, $3,576 and $14,337, against $5,032 on each date under the regular method. The total is the same $20,128. Only the timing changes, and it changes a lot. In the first half of the year the annualized schedule asks for $2,215 instead of $10,064.

What it saves in penalty

If this freelancer paid only the annualized amounts and filed under the regular method, the early installments would look short, and the penalty comes to about $396. Filing Form 2210 with Schedule AI removes it, because the schedule measures each installment against the annualized requirement. That is the entire purpose of the method.

Practical limits

The method is claimed on the return, not in advance, so keep monthly records of profit and the dates and amounts of every payment. It is more paperwork, and it only pays off when income is uneven. If your profit accrues evenly, the annualized schedule collapses into the regular one. The calculator’s annualized mode accepts the three cumulative profit figures and leaves any you skip at an even pace. Treat the output as a planning number and let Schedule AI or your preparer do the final computation.

The underpayment penalty is interest, not a fixed fee. It is charged on the unpaid part of each installment at the IRS underpayment rate, from the due date until you pay or April 15, whichever comes first. The rate is the federal short-term rate plus three percentage points, reset every quarter.

Take the $100,000 freelancer who owes $5,032.02 on each date under the 90% method. She misses September 15 and pays that installment along with the January 15 payment. The September shortfall is unpaid for 122 days at 7%: $5,032.02 × 7% × 122 ÷ 365 = $117.74. That is the whole penalty for a missed payment of that size, well under what most people expect.

The last row is the worst case for a $22,365 tax bill, and it is still $924. That is real money, but it is about 4% of the tax and far below the 20% and 25% penalties people fear. Those apply to different failures, such as not filing or not paying the balance by the deadline. The failure-to-pay penalty adds 0.5% of the unpaid tax for each month, up to 25%, and it is separate from the estimated tax penalty.

How the calculator applies payments

Payments are applied to the oldest unpaid installment first, which is how the IRS computes the penalty on Form 2210. If you skip April and pay double in June, the extra goes to April’s shortfall and stops that interest on June 15. Anything paid beyond the current installment carries forward to the next one. The estimate uses simple daily interest, so it can differ from Form 2210 by a few dollars.

Getting the penalty waived or cut

The IRS can waive the penalty when the underpayment resulted from a casualty, disaster or other unusual circumstance, or when you retired after age 62 or became disabled in the tax year or the year before and had reasonable cause. You request a waiver on Form 2210. The penalty is not deductible, and the interest rate for 2027 is unknown, so the calculator lets you set the rate it assumes after December 31, 2026.

All of the methods below credit the same payment. They differ in cost, speed and the record they leave.

The most common error is choosing the wrong payment type or year. Select Estimated Tax (1040-ES) and the correct tax year; a payment applied to the wrong year can leave your 2026 record short and require a call to fix. Keep the confirmation for every payment. When you file, you enter the total on Form 1040, and the IRS matches it against its records. The Direct Pay page and the EFTPS enrollment page are the two official starting points.

Paying more often than four times is allowed and sometimes smart. A monthly transfer keeps a tax account funded, and every extra payment counts on the date you make it. The IRS only checks the four due dates, so anything paid before a date counts toward that date.

If you have a job, you may not need to send estimated payments at all. Withholding counts toward the safe harbor, and it has a helpful timing rule: by default the IRS treats it as paid in equal amounts on each of the four due dates, regardless of when it was actually withheld. Raising your withholding in November therefore counts as if you had paid extra in April.

The calculator shows how this works. Take a single filer with a $60,000 salary, $5,200 of federal tax withheld for the year, and $25,000 of side profit. Total tax for the year is $11,992. If last year’s tax was $4,000 and her adjusted gross income was under $150,000, her required annual payment is $4,000, the prior-year test. Her $5,200 of withholding already exceeds it, so no estimated payments are needed and no penalty applies. The balance due at filing is still $6,792. She meets the safe harbor and still needs the cash in April.

Change one fact and the picture flips. If she had no prior-year return, the required amount is 90% of $11,992, which is $10,792. After $5,200 of withholding, $5,592 remains, or $1,398 on each due date, and $1,199 is left at filing. To avoid estimated payments, she would ask payroll to raise withholding through Step 4(c) of Form W-4 by enough to cover the gap over the remaining pay periods. Withholding is credited against her total tax, including the self-employment tax on the side income, so the extra amount does the same job as the payments would have.

Use the W-2 wages and withholding fields under the calculator’s optional section. For how the side income is taxed when it sits on top of a salary, including the effect of the Social Security cap, see the section on W-2 income on the 1099 tax calculator page.

Most states with an income tax want estimated payments too, and the rules are set separately. Thresholds are often lower than the federal $1,000, due dates usually match the federal ones but not always, and some states use unequal installments. This calculator is federal only. Treat the state as its own plan.

California is the example that catches people. Its individual schedule is 30% on April 15, 40% on June 15, nothing on September 15 and 30% on January 15. By June 15 the state expects 70% of the year’s estimated tax where the IRS expects 50%. The trigger is $500 of expected tax, not $1,000. A freelancer who mirrors the federal 25% schedule for California is short in April and June and pays a September installment the state does not want. The federal September 15 payment is unaffected: it is still due in full.

Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington and Wyoming do not tax wage or self-employment income, so there is nothing to estimate for them. For every other state, use the revenue department’s own worksheet, and count state payments as a separate line in your tax account.

Estimates are forecasts, and forecasts change. The way to adjust is a single formula: the new required annual payment, minus what you have paid and withheld so far, divided by the number of due dates left. The subtlety is that the missed part of the earlier installments still accrues penalty until you catch up.

Suppose you expected $60,000 of profit in January. Tax on that is $12,037, so 90% is $10,833, or $2,708 per date. You paid the first two. By mid-June it is clear the year will finish near $100,000, so the new requirement is $20,128, or $5,032 per date. You are behind by $2,324 on April 15 and by $4,648 on June 15, because each payment goes to the oldest shortfall first.

Catching up in September costs $103. Waiting until January roughly doubles it to $212. Skipping the catch-up leaves $4,648 to pay in April, along with the $2,236 that the 90% method always leaves, and the penalty grows to $292. The pattern generalizes. Adjust when you learn something, not when the next deadline forces you to.

When income falls or you overpay

If profit drops, re-run the estimate and lower the remaining payments. Money already paid is not lost. You can take it as a refund when you file, or apply the overpayment to next year’s estimated tax on your return. The trade-off is timing. Money parked at the IRS earns no interest until it becomes a refund, so trimming the remaining payments is better than waiting.

Start with the annual figure in the 1099 tax calculator, or compare a contractor rate against an employee salary with the employee vs. contractor calculator.