How Much Estimated Tax to Pay to Avoid a Penalty?

To avoid an IRS underpayment penalty, pay in — through withholding, estimated payments, or a mix — at least 90% of the tax you’ll owe for the current year or 100% of the total tax on last year’s return, whichever is smaller. If your adjusted gross income last year was more than $150,000 ($75,000 if you’re married filing separately), the prior-year figure climbs to 110%. That is the whole answer to how much estimated tax to pay to avoid a penalty, and the rest is detail: who the rule applies to, when the installments are due, and the handful of exceptions that can shrink the number or waive the penalty entirely.

Do You Even Owe Estimated Tax

The rules only bite if you expect to owe $1,000 or more when you file, after subtracting withholding and refundable credits. That threshold combines income tax, self-employment tax, and alternative minimum tax, so freelancers and sole proprietors cross it quickly.¹ Common triggers are self-employment earnings, rental income, investment gains, dividends, interest, and alimony.

There is one clean exemption. You skip estimated payments for the current year if last year you had zero tax liability, your tax year covered a full 12 months, and you were a U.S. citizen or resident the entire time.² Zero liability means your total tax was zero or you weren’t required to file. If that was you, this year’s expected bill doesn’t matter.

The Two Safe Harbors

Federal law gives you two paths. You only need to satisfy one:

Pay at least 90% of the tax you’ll owe on this year’s return, or
Pay at least 100% of the total tax shown on last year’s return.

The prior-year method is the predictable one because the number is fixed the moment you file last year’s return. It only works if that prior year was a full 12 months and you actually filed.² Whichever method produces the smaller required payment is the one the IRS holds you to. If 90% of your current-year tax works out to $8,000 and 100% of last year’s tax was $10,000, hitting $8,000 keeps you safe.

The required amount then gets split into four equal installments of 25% each.²

The 110% Rule for Higher Earners

If your adjusted gross income exceeded $150,000 last year ($75,000 if married filing separately), the prior-year safe harbor jumps from 100% to 110%.³ The 90%-of-current-year option stays at 90% regardless of income, so a high earner who can project this year’s tax accurately still has that route.

Say you earned $160,000 last year and owed $25,000 in tax. To lock in the prior-year safe harbor for the current year, you need to pay at least $27,500 across your four installments, not $25,000. Miss by a few hundred dollars and the penalty starts accruing on the shortfall.²

When Each Installment Is Due

For tax year 2026, the four due dates are:

April 15, 2026 (covers income from January 1 through March 31)
June 15, 2026 (covers April 1 through May 31)
September 15, 2026 (covers June 1 through August 31)
January 15, 2027 (covers September 1 through December 31)

If a due date falls on a weekend or legal holiday, the deadline shifts to the next business day. You can skip the January 15 payment entirely if you file your 2026 return and pay any balance owed by February 1, 2027.⁴ Notice the coverage periods are not equal calendar quarters. The second installment covers only two months, and people budgeting monthly sometimes underfund it.

Each quarter of underpayment is evaluated on its own. You can owe a penalty for one quarter even if you overpaid another, so meeting the annual total is not enough on its own — the installments themselves have to be on time.⁵

Withholding Counts, and It Backdates

If you receive a paycheck or a pension, there’s an easier route many people miss. File a new W-4 with your employer and use the line for an additional dollar amount withheld from each check.¹ Extra withholding counts the same as estimated payments toward the safe harbor.

The advantage is timing. Withholding is treated as paid evenly through the year even if you crank it up in November or December. That backdating can rescue you from a penalty late in the year, when it is too late to fix a missed spring or summer installment. Estimated payments get credited only when made; withholding gets spread across the year automatically.

If Your Income Is Uneven, Use the Annualized Method

The equal-installment rule assumes your income arrives in even quarters. That is fiction for a lot of people: real estate agents who close most deals in summer, consultants who land a big Q4 contract, anyone who sells stock late in the year. The annualized income installment method lets you base each quarter’s required payment on the income you actually earned through that quarter, rather than one-quarter of a full-year projection.⁶

If you earned almost nothing in Q1 and had a huge Q3, a small Q1 payment won’t be penalized as long as it matches your annualized income for that period. The catch is paperwork. You must complete Schedule AI on Form 2210, use the method for all four installments once you use it for one, and attach the form to your return. For genuinely lumpy income, it is usually worth the effort.

Farmers and Fishermen

If at least two-thirds of your gross income comes from farming or fishing, the math is more forgiving. Your required annual payment is the smaller of two-thirds (66.67%) of current-year tax or 100% of prior-year tax.³ You also only make one estimated payment, due January 15, instead of four. And you can skip estimated payments entirely if you file the return and pay the full balance by March 1.

What the Penalty Actually Costs

The underpayment penalty is essentially interest on the amount you should have paid for each quarter, running from the installment due date until you pay or until the return due date, whichever comes first. It accrues daily, so a $2,000 shortfall left unpaid for 90 days costs more than the same shortfall left for 30.⁵

The rate equals the federal short-term rate plus three percentage points, and the IRS resets it every quarter. For Q1 2026 the rate was 7%; for Q2 2026 it dropped to 6%.⁷⁸ The IRS generally calculates the penalty for you and sends a notice. You can also work it out yourself on Form 2210 to check the math or request a waiver.

When the IRS Will Waive the Penalty

The underpayment penalty does not qualify for standard “reasonable cause” relief the way most other IRS penalties do. Two narrow exceptions exist:

Casualty, disaster, or other unusual circumstance where imposing the penalty would be unfair. Attach supporting documentation (police reports, insurance claims, similar records) to Form 2210 with a written explanation.⁶
Retirement after reaching age 62 or disability during the tax year or the preceding year, where the underpayment was due to reasonable cause rather than neglect. Attach proof of retirement date and age, or documentation of the disability.³

In federally declared disaster areas, the IRS usually grants relief automatically and you don’t need to file Form 2210 at all. If a penalty notice still shows up after the automatic waiver period, call the IRS disaster hotline at 866-562-5227.⁶

State Estimated Tax Is Separate

Meeting the federal safe harbor does not cover you at the state level. Most states with an income tax also require estimated payments, with thresholds ranging from as low as $100 to as high as $2,000 in expected tax liability. Many states mirror the federal 90%/100% safe harbors, but some set their own benchmarks, and state penalty rates vary. Check your state tax agency’s rules directly.

1
Internal Revenue Service. Estimated Taxes
2
Office of the Law Revision Counsel. 26 USC 6654 – Failure by Individual to Pay Estimated Income Tax
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Internal Revenue Service. Underpayment of Estimated Tax by Individuals Penalty
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Internal Revenue Service. 2026 Form 1040-ES Estimated Tax for Individuals
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Internal Revenue Service. Instructions for Form 2210 (2025)
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Internal Revenue Service. Instructions for Form 2210 – Underpayment of Estimated Tax by Individuals, Estates, and Trusts
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Internal Revenue Service. Interest Rates Remain the Same for the First Quarter of 2026
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Internal Revenue Service. Internal Revenue Bulletin 2026-08