Estimated tax for 2026: the safe harbor and how to catch up by January 15

If you're self-employed or have income with no tax withheld, the IRS expects you to pay during the year. You avoid the underpayment penalty by paying at least a safe-harbor amount through withholding and estimated payments. Every figure below comes from our estimated tax safe harbor calculator, which matches the example in IRS Publication 505 (2026).

The rule

• No penalty if you'll owe less than $1,000 after withholding and credits.
• Otherwise, withholding plus estimated payments must reach the smaller of 90% of your 2026 tax and 100% of your 2025 tax (your 2025 return must cover 12 months).
• If your 2025 AGI was over $150,000 ($75,000 married filing separately), the second test is 110% of your 2025 tax.
• Farmers and fishers: 66⅔% of this year's tax, and the 110% rule doesn't apply.

"Tax" means the total tax on your return, including self-employment tax, before withholding and payments. The publication's own example: 90% of an expected $71,253 is $64,128; 110% of the previous year's $42,581 is $46,839, so $46,839 is enough.

Example 1: a freelancer with some withholding

Total tax on the 2025 return: $18,000, AGI $110,000. Expected 2026 tax: $24,000. A part-time job withholds $3,000. The safe harbor is the smaller of $21,600 (90% of 2026) and $18,000 (100% of 2025): $18,000. Less withholding, $15,000 of estimated payments, $3,750 a quarter. Having paid $7,500 so far, $7,500 is still to pay by January 15, 2027, and about $6,000 would be left to pay with the return in April.

Example 2: higher income

2025 tax $40,000 on an AGI of $200,000; expected 2026 tax $60,000; no withholding. The prior-year test is 110%: $44,000, lower than 90% of this year's tax ($54,000). That's $11,000 a quarter. Someone who has paid $22,000 still needs $22,000 by January 15, and would owe $16,000 when filing.

Example 3: when this year's tax is lower

If 2026 is a slower year, $15,000 of tax against $22,000 in 2025, the 90% test is the smaller: $13,500. With $4,000 withheld, $9,500 of estimated payments is enough.

If you're behind

The four payments for 2026 are due April 15, June 15 and September 15, 2026, and January 15, 2027, each a quarter of the year's amount. Paying the rest by January 15 stops the penalty from growing, but a quarter that was short can still owe a little for the time it was short. Withholding is treated as paid evenly through the year, whenever it actually came out, so raising withholding from a paycheck or an IRA distribution late in the year can cover earlier quarters.

Check your own numbers in the safe harbor calculator, and set money aside as you earn with the freelancer tax set-aside calculator.