Estimated Tax Deadlines for 2026 and the Safe Harbor Rule

The 2026 estimated tax payments are due April 15, 2026, June 15, 2026, September 15, 2026 and January 15, 2027, per the 2026 Form 1040-ES. To avoid an underpayment penalty, you don’t have to prepay your whole tax bill. You need to pay at least the smaller of 90% of your 2026 tax or 100% of your 2025 tax (110% if your 2025 AGI was over $150,000), spread across those dates. That’s the “safe harbor.” Below: the dates, how the safe harbor works, and what the penalty costs if you miss it.

The 2026 due dates

The payment periods aren’t equal quarters. They cover three, two, three and four months, per Publication 505 (2026). A few rules around the dates:

• Weekends and holidays. If a due date falls on a Saturday, Sunday or legal holiday, the payment is on time the next business day. None of the 2026 dates falls on a weekend.
• The January payment is optional if you file early. You don’t have to make the January 15, 2027 payment if you file your 2026 return by February 1, 2027 and pay the entire balance due with it, per Form 1040-ES.
• Mailed payments. The U.S. postmark date counts as the payment date. The 2026 instructions warn that the postmark is the date the payment is processed at a postal facility, which may be later than the day you drop it off. Paying electronically avoids that problem.
• Starting mid-year. If you first have income subject to estimated tax after March 31, your first payment is due at the end of the period when that income arrives. For example, a freelancer whose first client pays in July makes the first payment by September 15, per Publication 505’s Table 2-1.

As of late September 2026, the first three deadlines have passed. The next one is January 15, 2027.

The safe harbor rule

The 2026 Form 1040-ES instructions spell out when estimated payments are required. Read the other way round, they tell you how to avoid the penalty. You’re in the clear if either of these is true:

1. You’ll owe less than $1,000 for 2026 after subtracting withholding and refundable credits, or
2. Your withholding and refundable credits, plus your on-time estimated payments, equal at least the smaller of:
   • 90% of the tax on your 2026 return, or
   • 100% of the tax on your 2025 return. Your 2025 return has to cover all 12 months.

For higher earners, the prior-year figure becomes 110% if your 2025 AGI was more than $150,000, or $75,000 if your 2026 filing status is married filing separately. Farmers and fishermen get their own rule: 66⅔% instead of 90%.

There’s also a full exemption: if you were a U.S. citizen or resident alien for all of 2025 and had no tax liability for 2025, you don’t have to pay 2026 estimated tax at all.

Why the prior-year option is so useful

You know last year’s tax exactly. It’s on your return. You can’t know this year’s tax until the year is over. So for a freelancer whose income is growing, paying 100% (or 110%) of last year’s tax in four equal installments is a way to be certain you won’t owe a penalty, whatever this year turns out to be. You’ll still owe the difference when you file, but without a penalty on top.

Example: picking the smaller safe harbor

Say you expect $40,000 of total federal tax for 2026. Your 2025 return showed $30,000 of tax on an AGI of $180,000, above the $150,000 line, so the 110% version applies.

Paying $8,250 by each due date keeps this freelancer penalty-free. The remaining $7,000 ($40,000 − $33,000) is due with the return in April 2027.

Each payment has to be on time, not just the total

The penalty is figured separately for each payment period. If your first-quarter payment was short, paying extra in September doesn’t erase the penalty on the earlier shortfall. Publication 505 notes you can owe a penalty even if you’re due a refund when you file.

If your income is uneven, you don’t have to pretend it arrived evenly. The annualized income installment method in Publication 505 bases each required payment on what you actually earned through that period. That can lower the early payments for someone whose income lands late in the year. You claim it on Form 2210, Schedule AI, filed with your return.

How much the penalty actually costs

The penalty works like interest. It’s based on the amount you underpaid, how long it stayed unpaid, and the IRS’s quarterly underpayment interest rate, per the IRS penalty page. For the quarter beginning October 1, 2026, that rate is 7% a year for individuals (IR-2026-98).

The Form 2210 penalty worksheet figures it as underpayment × days unpaid ÷ 365 × rate. So a $2,000 shortfall left unpaid for 90 days at 7% costs about $35 ($2,000 × 90 ÷ 365 × 7% = $34.52). It’s not catastrophic, but it keeps growing every day the shortfall stays unpaid.

If you’ve fallen behind this year

1. Pay the shortfall as soon as you can. The penalty runs day by day on each underpaid amount, so a payment now stops it from growing on whatever you cover.
2. Refigure what you owe. Publication 505’s amended estimated tax worksheet has you pay 100% of your refigured required annual payment, minus what you’ve already paid, by the January 15, 2027 installment.
3. Consider filing early. Filing your full 2026 return by February 1, 2027 and paying the balance replaces the January payment, though it doesn’t undo any penalty on earlier periods.
4. Check the waiver rules. The IRS may waive the penalty for a casualty, disaster or other unusual circumstance, or if you retired after age 62 or became disabled with reasonable cause. See the instructions for Form 2210.

Bottom line

Put the four dates in your calendar: April 15, June 15, September 15 and January 15. For each one, aim to have paid a quarter of the smaller of 90% of this year’s tax or 100% of last year’s (110% above $150,000 of AGI). The prior-year option is the simplest, because you already know the number. To figure your installment from scratch, see Quarterly Estimated Taxes for the Self-Employed. To see how much to keep aside as you go, see How Much Should a Freelancer Set Aside for Taxes?