How it works
Tax is due as you earn, so income with nothing withheld (freelance work, a side business, interest, rent, retirement withdrawals) calls for quarterly payments on Form 1040-ES. The calculator works out your whole 2026 federal tax: self-employment tax on business profit, and income tax after the standard deduction, the qualified business income deduction and the child tax credit. It then subtracts what your paychecks withhold and schedules the rest across the due dates you have left.
Required for the year = the smaller of 90% of 2026 tax and 100% of 2025 tax (110% above $150,000 AGI), less withholding
If you're starting late or catching up, it follows the IRS's own method, Worksheet 2-12 in Publication 505. The next payment brings you up to the share due by that date (half by June 15, three quarters by September 15, all of it by January 15), and anything left is split over the later dates.
Worked example
A single employee earns $60,000 with $5,500 withheld, plus $25,000 from a side business, and hasn't paid any estimated tax. Their 2026 federal tax is $11,992, including $3,532 of self-employment tax. The required amount for the year is 90% of that, $10,792, and withholding covers $5,500. In late September only the January 15 payment is left, so it has to cover the other $5,292, or $6,492 to owe nothing in April.
The three quarters already missed may still carry a small penalty, figured like interest. Putting the extra through withholding from the last paychecks of the year avoids that, because withholding counts as paid evenly through the year.
A full-time freelancer expects $70,000 of profit, paid $7,500 in estimated tax by September, and owed $12,000 in total last year. This year's tax is $14,342, but 100% of last year's, $12,000, is the smaller safe harbor. So the January payment only needs to be $4,500, with the remaining $2,342 due when they file. Having paid less than three quarters of $12,000 by September 15, they may still owe a small penalty for the earlier quarters.
Who has to pay estimated tax
You generally need to make estimated payments if you expect to owe $1,000 or more when you file, after withholding and refundable credits, and your withholding will cover less than the required amount above. A W-2 job with enough withholding can cover a side income on its own, which is why the calculator counts it.
Behind on payments?
- Pay now. The penalty works like interest, figured separately for each quarter, so paying sooner stops it growing.
- Or raise your withholding. The IRS treats tax withheld from pay as paid in equal parts through the year, whenever it came out, so extra withholding in the fall covers the earlier quarters too. The W-4 withholding calculator works out how much per paycheck.
- Skip January by filing early. If you file your 2026 return by January 31, 2027 and pay what's left, you don't need the January 15 payment.
- Uneven income. If most of your income came late in the year, the annualized income installment method (Form 2210, Schedule AI) can lower or remove the penalty for the early quarters.
Things to know
- This is an estimate, not tax advice. It treats other income as ordinary income, so long-term gains and qualified dividends, taxed at lower rates, come out a little high (see the capital gains tax calculator). It leaves out the 3.8% net investment income tax, itemized deductions, other credits and state estimated tax.
- Only self-employment? The self-employment tax calculator breaks down Social Security, Medicare and the QBI deduction on 1099 income.
- 2027. The IRS usually publishes next year's figures in October or November. We'll add the 2027 figures once it does.
Questions people ask
Do I have to pay estimated tax if I also have a W-2 job?
Only if your withholding falls short. If it covers the required amount above, or you'd owe less than $1,000, you don't. You can also raise withholding on a new W-4 instead of sending quarterly payments.
What happens if I miss a quarterly payment?
You may owe an underpayment penalty, figured like interest on the amount that was late, for the days it was late. Pay as soon as you can; the calculator folds the missed amount into your next payment.
Can I pay all my estimated tax at once?
Yes. Paying the whole year's amount by April 15 covers every quarter. Paying it all in January covers the last quarter but not the earlier ones.
How do I pay?
Online through IRS Direct Pay (from a bank account, free), your IRS online account or EFTPS; by debit or credit card through an IRS-approved processor, which charges a fee; or by check with a Form 1040-ES voucher.
Sources
- IRS: Form 1040-ES, estimated tax for individuals
- IRS: Publication 505, Tax Withholding and Estimated Tax (2026), including Worksheet 2-12
- IRS: Topic 306, penalty for underpayment of estimated tax
- IRS: Instructions for Form 2210 (withholding counted in equal parts)
- IRS: Rev. Proc. 2025-32 (2026 brackets, standard deduction, QBI thresholds)
- IRS: ways to pay
Reviewed September 29, 2026 by The Dollars World team. How we build and check our calculators · Our data and formulas. This is general information, not financial advice.