How to use this calculator
- Choose the tax year, your filing status and your children under 17.
- Tick the kinds of income you'll have this year. For self-employment, enter your best estimate of the year's profit: what you'll be paid less business expenses, from your Schedule C if you have last year's as a guide. For a job, enter your wages and the federal income tax you expect withheld for the whole year: your pay stub's year-to-date figure plus the rest of the year.
- Enter two numbers from last year's return: the total tax, less refundable credits, and your adjusted gross income. They set the safe harbor.
- If you've already made payments this year, turn that on and enter the total and your next due date. The calculator works out what to pay from here.
- Under More options, add itemized deductions, other adjustments, age 65 and other dependents.
The numbers already filled in are an example. Replace them with your own, and run it again when your income changes during the year.
How it's calculated
The rules come from section 6654 of the tax code, Form 1040-ES and Form 2210. The calculator figures your federal tax for the year the way your return will, then the amount you must prepay through withholding and estimated payments, then the payments themselves.
Your tax for the year
Say you file single for 2026 and expect $80,000 of self-employment profit and no other income. Self-employment tax is 15.3% of 92.35% of the profit, $11,304, and half of it is deducted from your income, which leaves adjusted gross income of $74,348. After the standard deduction and the qualified business income deduction of $11,650, taxable income is $46,599 and income tax is $5,341. Your 2026 tax is $16,645.
The amount you must prepay
The law requires the smaller of 90% of this year's tax, here $14,980, and 100% of last year's tax, $13,000 in the example. So $13,000 is enough to avoid the penalty, paid as $3,250 on each of April 15, 2026, June 15, 2026, September 15, 2026 and January 15, 2027. You'd still owe $3,645 when you file, with no penalty on it. If last year's adjusted gross income was over $150,000 ($75,000 if you file separately this year), last year's test is 110%: with $60,000 of tax last year, that's $66,000. If you owed no tax at all last year, no payments are required, and neither are they if your tax less withholding comes to under $1,000.
Withholding counts as paid evenly
Tax withheld from wages or a pension counts as paid in four equal parts on the due dates, whenever it's actually taken out. Take someone with a $90,000 salary and $9,000 withheld, plus $20,000 of profit from a side business, whose tax last year was $14,000. Their 2026 tax is $17,069 and they must prepay $14,000. Withholding covers $9,000 of it, so they need $1,250 a quarter, or $5,000 more withheld from their pay by December 31. Because withholding counts evenly, extra withholding late in the year also covers an earlier quarter that was missed.
If you're behind
The calculator uses the IRS's Amended Estimated Tax Worksheet. In the first example, if you paid $3,250 in April and nothing in June, your next payment, due September 15, 2026, is $6,500, and then $3,250 by January 15, 2027. The penalty runs on the June shortfall until it's paid.
The penalty
The penalty works like interest: the IRS underpayment rate, the federal short-term rate plus 3 points, on each underpaid installment from its due date until it's paid. The calculator figures it the way Form 2210 does, rate period by rate period, using each quarter's published rate. Every payment, withholding included, goes to the oldest unpaid installment first, which is the order the law sets. If the person in the first example made no estimated payments and paid everything with their return on April 15, 2027, the penalty would be about $597. The IRS hasn't announced its rates for the first months of 2027 yet, so the calculator uses the latest one, 7%, and says so.
Assumptions and limits
- Your income is your estimate for the whole year, earned evenly. If most of it comes late in the year, the annualized income installment method can lower the earlier payments; this calculator uses the regular method.
- Withholding counts as paid in four equal parts on the due dates, as the law treats it unless you show the actual dates. Pre-tax 401(k), 403(b), 457(b) and SIMPLE IRA contributions come out of your box 1 wages but not your Social Security and Medicare wages, so the calculator adds back what you enter for them under More options: they use up the Social Security wage base before your self-employment income does, and they count toward the Additional Medicare Tax. Each person is assumed to have one employer.
- It figures income tax, self-employment tax, the Additional Medicare Tax, the net investment income tax on interest, dividends and gains, the child tax credit and the credit for other dependents. It doesn't figure the alternative minimum tax, household employment taxes, the earned income, education, child care, energy or premium tax credits, the 2026 charitable deduction for people who don't itemize, or the additional deduction for blindness.
- For self-employment it assumes a profit of at least $0, no farm income and no optional methods on Schedule SE. On a joint return, each spouse's self-employment tax is figured on their own profit and wages. The qualified business income deduction assumes no employees paid W-2 wages and no business property, which makes it smaller than it may be above the income threshold. If your business is a specified service business (health, law, accounting, consulting and financial services among them), tick the box under More options: above the threshold only part of its income counts toward the deduction, and none of it once taxable income passes the top of the range. A partner's guaranteed payments are self-employment income but not qualified business income, and this treats all profit as both.
- Net capital losses can't be entered. A withdrawal from an IRA or 401(k) before 59½ may owe a 10% additional tax that this doesn't add. The earned income and premium tax credits aren't figured, so for some lower-income households the tax shown is higher than it will be.
- On a separate return with Social Security benefits, the taxable part is figured as if you lived with your spouse at some time in the year, which makes more of it taxable.
- The penalty shown assumes no estimated payments, withholding counted evenly, and the rest paid with your return on April 15. It does not cover penalty waivers, and it is not the penalty for your actual payment dates.
- It doesn't cover farmers and fishers, fiscal-year taxpayers, nonresident aliens, or state estimated tax.
Input field details
What to enter in each box, where to find the number, and how this calculator treats it. When two calculators give different answers from the same numbers, it's usually because they handle one of these differently.
Filing status
The status you expect to file under for this tax year.
How this tool treats itIt sets your tax rates and standard deduction, and two estimated tax rules: a married person filing separately this year uses $75,000 instead of $150,000 for the 110% test on last year’s income, and the Additional Medicare Tax starts at $250,000 on a joint return, $125,000 on a separate one and $200,000 otherwise.
Children under 17
The number of children you can claim who are under 17 at the end of the year.
How this tool treats itEach brings the child tax credit, and part of it can be refunded even when you owe no income tax. The estimated tax rules subtract that refundable part from your tax. Assumes each child, and you, have a Social Security number valid for work.
Allowed range0 to 10
Self-employment net profit
Your best estimate of the year’s profit from freelance, contract, gig or business work: what you’ll be paid, less business expenses, for the whole year.
Where to find itSchedule C, line 31 (last year’s is a starting point). Payers report gross amounts on Forms 1099-NEC and 1099-K.
How this tool treats itSelf-employment tax is 15.3% (12.4% for Social Security, up to the year’s wage base less your wages, and 2.9% for Medicare) on 92.35% of the profit, none when that is under $400. Half of it is deducted from your income. The qualified business income deduction then takes up to 20% of the profit, less that half and your self-employed health insurance and retirement contributions. The tool assumes the profit arrives evenly through the year; if most of it comes late, the annualized income installment method on Form 2210 can lower the earlier payments.
Allowed range$0 to $5,000,000
Not includedA loss, farm income (Schedule F) and the optional methods of Schedule SE.
Your spouse’s self-employment net profit
On a joint return, your spouse’s own profit, if they are self-employed too.
Where to find itTheir Schedule C, line 31.
How this tool treats itEach spouse figures self-employment tax on their own profit, against their own wages for the Social Security wage base. The two businesses share one qualified business income deduction.
Allowed range$0 to $5,000,000
Wages
Your wages for the whole year. On a joint return, your own; your spouse’s go in the next field.
Where to find itForm W-2, box 1. With more than one job, add them.
How this tool treats itWages also lower the Social Security part of your self-employment tax once the two together pass the wage base, and they count first toward the Additional Medicare Tax threshold: 0.9% on wages and self-employment earnings above it. Your employer withholds that 0.9% on wages over $200,000, and the tool counts it as withholding. Box 1 stands in for boxes 3 and 5; pre-tax 401(k) deferrals make those higher.
Allowed range$0 to $5,000,000
Your spouse’s wages
On a joint return, your spouse’s wages for the whole year.
Where to find itTheir Form W-2, box 1.
Allowed range$0 to $5,000,000
Federal income tax withheld for the year
The federal income tax you expect to have withheld from wages, pensions and IRA withdrawals for the whole year, both spouses on a joint return.
Where to find itYour latest pay stub’s year-to-date federal withholding, plus what the remaining paychecks will withhold. Last year it was Form W-2, box 2, and Form 1099-R, box 4.
How this tool treats itThe law counts withholding as paid in four equal parts on the due dates, however late in the year it is taken out. So extra withholding in the fall counts toward the April and June payments too, which an estimated payment made in the fall does not.
Allowed range$0 to $5,000,000
Not includedSocial Security and Medicare tax withheld, and excess Social Security tax from two employers.
Interest, ordinary dividends and short-term gains
Taxable interest, nonqualified dividends and gains on investments you held a year or less.
Where to find itForms 1099-INT, 1099-DIV (box 1a less box 1b) and 1099-B.
How this tool treats itTaxed at your ordinary rates. With the next field, this is your net investment income: 3.8% applies to the smaller of it and your adjusted gross income over $200,000 ($250,000 on a joint return or as a surviving spouse, $125,000 separately).
Allowed range$0 to $5,000,000
Not includedRents, royalties, passive business income and annuities, which can also be net investment income, and investment expenses.
Qualified dividends and long-term gains
Qualified dividends and gains on investments you held more than a year, net of losses.
Where to find itForm 1099-DIV, box 1b, and long-term sales on Form 1099-B.
How this tool treats itTaxed at 0%, 15% or 20%, stacked on top of your other taxable income.
Allowed range$0 to $5,000,000
Pensions, IRA withdrawals and other income
The taxable part of pensions, annuities, IRA and 401(k) withdrawals, plus unemployment and any other taxable income not entered above.
Where to find itForm 1099-R, box 2a; Form 1099-G for unemployment.
Allowed range$0 to $5,000,000
Social Security benefits
The total benefits you expect for the year, both spouses on a joint return.
Where to find itForm SSA-1099, box 5.
How this tool treats itUp to 85% is taxable, depending on your other income. On a separate return the tool assumes you lived with your spouse at some point in the year, which makes more of it taxable.
Allowed range$0 to $500,000
Last year’s total tax
The total tax on last year’s return, less its refundable credits.
Where to find itFor 2026 payments: your 2025 Form 1040, line 24, less lines 27a through 30. For 2025 payments: your 2024 Form 1040, line 24, less lines 27 through 29.
How this tool treats itThe law requires you to prepay, through withholding and estimated payments, the smaller of 90% of this year’s tax and 100% of last year’s: the required annual payment, often called the safe harbor. When last year’s adjusted gross income was over $150,000 ($75,000 if you file separately this year), last year’s test is 110%. If you’ll file jointly this year after filing separately last year, add both returns’ amounts. A total of $0 means you owed no tax last year, and then no payments are required.
Allowed range$0 to $10,000,000
Last year’s adjusted gross income
The adjusted gross income on last year’s return.
Where to find itFor 2026 payments: your 2025 Form 1040, line 11a. For 2025 payments: your 2024 Form 1040, line 11.
How this tool treats itIt only decides whether last year’s test is 100% or 110%: over $150,000, or over $75,000 if you file separately this year.
Allowed range$0 to $10,000,000
Estimated payments made so far
The estimated tax you’ve already paid for this year, including any refund from last year you applied to it.
Where to find itYour IRS online account’s payment history, or your bank records.
How this tool treats itEstimated tax is the tax you pay during the year on income with no withholding. When payments fall short of what was due by a date, the underpayment penalty is interest at the IRS rate on the shortfall, from the due date until it is paid. The tool figures the rest of the year with the IRS Amended Estimated Tax Worksheet: what was due by your next date, less what you’ve paid, then the remainder split over the dates left.
Allowed range$0 to $10,000,000
Your next payment is due
The next due date that hasn’t passed yet.
Last year’s return
Whether you filed a return covering all of last year.
How this tool treats itIf you didn’t file one, or last year was a short tax year, only the 90% test applies. If you owed no tax at all last year because no return was required, no payments are required this year, as long as you were a U.S. citizen or resident for all of last year.
Self-employed health insurance and retirement contributions
Your deduction for self-employed health insurance and your contributions to a SEP, SIMPLE or solo 401(k) as the owner.
Where to find itSchedule 1 (Form 1040), lines 16 and 17.
How this tool treats itThey lower your income and the profit the qualified business income deduction is figured on.
Allowed range$0 to $1,000,000
Pre-tax retirement contributions from pay
What you (and, on a joint return, your spouse) will put into a 401(k), 403(b), 457(b) or SIMPLE IRA from pay this year, before tax. Leave out Roth contributions, which are already in your wages.
Where to find itYour pay stubs; on Form W-2, box 12, codes D, E, F, G and S (General Instructions for Forms W-2 and W-3, box 3).
How this tool treats itThey come out of the wages in box 1 but are still Social Security and Medicare wages (boxes 3 and 5), so they don’t lower those taxes. Here they raise the wages that use up the Social Security wage base before self-employment income, and the wages counted for the Additional Medicare Tax.
Allowed range$0 to $100,000
Specified service business
Tick if your business is in health, law, accounting, actuarial science, the performing arts, consulting, athletics, financial or brokerage services, investing or investment management, trading or dealing in securities, partnership interests or commodities, or earns its income from your reputation or skill (endorsements, appearance fees, licensing your name).
Where to find itIRC 199A(d)(2) and the Instructions for Form 8995-A, Schedule A.
How this tool treats itIt matters only when taxable income before the deduction is above the threshold: then only part of the business’s income counts toward the qualified business income deduction, and none of it once taxable income passes the top of the range.
Other adjustments to income
Other deductions taken before adjusted gross income: a deductible IRA contribution, an HSA contribution made outside payroll, alimony paid under an older agreement.
Where to find itSchedule 1 (Form 1040), Part II.
Allowed range$0 to $1,000,000
Itemized deductions
Your total itemized deductions, if you itemize.
Where to find itSchedule A, already limited.
How this tool treats itThe larger of this and your standard deduction is used.
Allowed range$0 to $5,000,000
Other dependents
Dependents who don’t qualify for the child tax credit, such as a child 17 or older or a parent you support.
How this tool treats itEach brings a $500 credit, which is not refundable.
Allowed range0 to 10
65 or older
Tick if you (and, on a joint return, your spouse) will be 65 or older at the end of the year.
How this tool treats itIt adds to the standard deduction and, for 2025 through 2028, brings the senior deduction of up to $6,000 a person, reduced above $75,000 of income ($150,000 joint).
Overtime, tips and car loan interest deductions
Your qualified overtime, qualified tips and car loan interest deductions for the year, added together.
Where to find itSchedule 1-A (Form 1040).
How this tool treats itThey come after adjusted gross income, like the standard deduction. The senior deduction is figured for you from the age boxes.
Allowed range$0 to $60,000
Questions
Who has to pay estimated tax?
Should I base my payments on last year's tax or this year's?
I also have a job. Do I still need to make payments?
What if I missed a payment?
How big is the penalty?
My income is uneven. Do I have to pay the same each quarter?
Can I skip the January payment?
Do I pay state estimated tax too?
Version history
- October 8, 2026 (version 1.0.0): First version: the year's federal tax with self-employment tax, the payment that avoids the underpayment penalty, catch-up payments and the penalty if you pay nothing, for 2025 and 2026.