A quarterly estimated tax calculator works out how much federal tax to send the IRS each quarter when tax is not withheld from your income. A single freelancer with $80,000 of net self-employment income owes about $18,830 for 2026, but paying last year’s tax in four equal parts meets the safe harbor.
On this page
How to use the quarterly estimated tax calculator
- Enter net self-employment income and other income for the year.
- Choose your filing status.
- Enter last year’s total tax and AGI from your return.
- Enter any federal tax withheld this year.
- Read the quarterly payment, the safe-harbor target and your total estimated tax.
What formula does the quarterly estimated tax calculator use?
- Self-employment (SE) tax = 92.35% of net SE income × 12.4% (up to the $184,500 Social Security wage base for 2026) + 92.35% × 2.9% Medicare
- Additional Medicare tax = 0.9% of SE earnings above $200,000 ($250,000 married filing jointly, $125,000 married filing separately), per IRS Topic 560
- AGI = other income + SE income − half of SE tax
- Income tax = 2026 brackets applied to AGI − the standard deduction
- Required annual payment = the smaller of 90% of this year’s tax or 100% of last year’s tax (110% if last year’s AGI was over $150,000, or $75,000 if married filing separately). If you leave last year’s tax blank, the quarterly estimated tax calculator uses 90% of this year’s tax
- Each quarterly payment = (required payment − withholding) ÷ 4
Quarterly estimated tax calculator worked example
A single freelancer with $80,000 of net self-employment income and no other income:
| Item | Amount |
|---|---|
| SE tax | $11,303.64 |
| AGI | $74,348.18 |
| Taxable income after $16,100 standard deduction | $58,248.18 |
| Income tax (2026 brackets) | $7,526.60 |
| Total tax | $18,830.24 |
| 90% of this year | $16,947.22 |
If last year’s total tax was $12,000, that is the smaller safe-harbor figure, so paying $3,000 a quarter avoids an underpayment penalty, even though the full bill will be higher at filing time. The quarterly estimated tax calculator does not include the qualified business income deduction, credits or state tax, which can change the result.
2026 estimated tax due dates
| Payment | Income earned | Due date |
|---|---|---|
| 1 | Jan 1 – Mar 31 | April 15, 2026 |
| 2 | Apr 1 – May 31 | June 15, 2026 |
| 3 | Jun 1 – Aug 31 | September 15, 2026 |
| 4 | Sep 1 – Dec 31 | January 15, 2027 |
When a date falls on a weekend or legal holiday, the payment is due the next business day.
Who must pay estimated tax
The IRS says you generally must make estimated payments if you expect to owe at least $1,000 after withholding and credits. Freelancers, gig workers, landlords and investors often do. You can pay through IRS Direct Pay, your IRS online account or EFTPS, and Form 1040-ES has a worksheet. Employees with a side income can instead raise withholding at their main job with a new Form W-4.
Uneven income
If most of your income arrives late in the year, the annualized income installment method on Form 2210 can lower or remove the penalty for early quarters. Track income each quarter and adjust the next payment rather than waiting for the return. Keep confirmation numbers for every payment so you can report them correctly on Form 1040.
Estimates for education only, not tax, legal or financial advice. Check current rules with the tax authority or a qualified adviser.
Safe harbor payments
You can avoid the underpayment penalty without predicting this year’s income exactly. The IRS treats you as paid up if your withholding and estimated payments cover at least 90% of this year’s tax or 100% of last year’s tax, rising to 110% of last year’s tax if last year’s adjusted gross income was over $150,000.
Say last year’s total tax was $12,000 and your AGI was $120,000. Paying $3,000 on each of the four due dates meets the 100% rule, even if your income jumps this year. You may still owe a balance in April, but no penalty. If income falls, the 90% rule may let you pay less. A quarterly estimated tax calculator helps with both: enter last year’s tax to see the safe harbor amount, and an estimate of this year’s to see whether paying less is reasonable. If you miss a date, rerun the quarterly estimated tax calculator and pay as soon as you can, because the penalty works like interest and grows with each day late.
Related converters and calculators
Related calculators:
- Income tax calculator: federal tax
- Salary tax calculator: take-home
- Overtime tax calculator: overtime deduction
- Rental property calculator: rental income
Self-employed? The self-employment tax calculator and the 1099 tax calculator break down what you may owe.
Sources
IRS: Estimated taxes; IRS: About Form 1040-ES; IRS Rev. Proc. 2025-32 (2026 brackets and standard deduction); IRS: Self-employment tax.
Questions about this calculator
When are 2026 estimated taxes due?
April 15, June 15 and September 15, 2026, and January 15, 2027.
How do I avoid an underpayment penalty?
Pay at least 90% of this year’s tax or 100% of last year’s (110% if last year’s AGI was over $150,000), spread evenly.
Do I need to pay estimated tax?
Generally yes if you expect to owe $1,000 or more after withholding and credits.
Is self-employment tax included?
Yes. The calculator adds Social Security and Medicare tax on 92.35% of net SE income.
Does it include state tax?
No. Check your state’s estimated tax rules separately.
Check the assumptions and units before relying on a result. Financial, tax and health estimates do not replace advice for your individual circumstances.
Report a calculation issue