Quarterly Tax Calculator
Enter your estimated tax and last year's numbers to calculate 2026 quarterly estimated payments under the IRS safe harbor, with all four due dates.
110% safe harbor applies above $150,000 prior-year AGI.
From a job's W-2 withholding, if any.
Required annual payment
$19,000.00
The smaller safe-harbor path
Still due via estimates
$15,000.00
Per quarter
$3,750.00
90% of this year
$19,800.00
| Payment | Due date | Amount |
|---|---|---|
| Q1 (income Jan 1 - Mar 31, 2026) | April 15, 2026 | $3,750.00 |
| Q2 (income Apr 1 - May 31, 2026) | June 15, 2026 | $3,750.00 |
| Q3 (income Jun 1 - Aug 31, 2026) | September 15, 2026 | $3,750.00 |
| Q4 (income Sep 1 - Dec 31, 2026) | January 15, 2027 | $3,750.00 |
Prior-year safe harbor used: $19,000 (100% of last year's tax).
How it's calculated
The required annual payment is the smaller of two safe-harbor paths:
min(90% × this year's estimated tax, 100or110% × last year's tax)
Subtract any tax already withheld this year, and split what's left across the four quarterly due dates.
Worked example
The calculator's own defaults: $22,000 estimated tax this year, $19,000 total tax last year on $120,000 AGI (under the $150,000 high-income threshold, so the 100% path applies), with $4,000 already withheld.
| 90% of this year's tax | $19,800.00 |
| 100% of last year's tax | $19,000.00 |
| Required annual payment (the smaller one) | $19,000.00 |
| Per quarter, after withholding | $3,750.00 |
Frequently Asked Questions
Who needs to pay quarterly estimated tax?
Anyone who expects to owe $1,000 or more in federal tax for the year after subtracting withholding -- typically the self-employed, freelancers, and anyone with significant investment, rental or other income that doesn't have tax withheld from it. If you're a W-2 employee with enough withholding to cover your bill, you generally don't need to file these.
What is the safe harbor, exactly?
You avoid an underpayment penalty if you pay, over the year (through withholding and estimated payments combined), the smaller of 90% of this year's actual 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). Using last year's number is often easier since it's already known, while this year's isn't final until you file.
What happens if I underpay?
The IRS can charge an underpayment penalty, calculated roughly like interest on the shortfall for each period it went unpaid -- it's not a flat fee, and it compounds the longer the gap goes uncorrected. Paying at least the safe-harbor amount by each due date avoids it entirely, even if you still owe more when you file.
What are the 2026 due dates?
Q1: April 15, 2026; Q2: June 15, 2026; Q3: September 15, 2026; Q4: January 15, 2027. Source: IRS Form 1040-ES.
Do I have to pay the exact same amount every quarter?
No -- the IRS lets you use the annualized income installment method if your income is uneven through the year (common for seasonal businesses), paying more in quarters when you actually earned more. This calculator uses the simpler even-split default; if your income is lumpy, the annualized method can reduce or eliminate a penalty an even split would otherwise trigger.
This is an estimate from the inputs you enter and the published rates above, not tax advice, and this site is not affiliated with the IRS, any state revenue department, or the Social Security Administration. Real tax bills involve credits, deductions and filing details this tool can't model -- see the Terms.