If you miss an estimated tax payment, the IRS charges an underpayment penalty that works like interest on the shortfall, compounding daily from the missed due date until you either pay the amount or file your return. For the first quarter of 2026, that rate is 7% per year.1Internal Revenue Service. Quarterly Interest Rates The penalty on a single missed quarter is usually modest, and paying as soon as you can stops additional interest from stacking up. Several rules can also wipe out the penalty entirely if you meet them.
How the Penalty Is Calculated
The IRS doesn’t hit you with a flat fine for missing a deadline. Under Section 6654 of the Internal Revenue Code, the penalty is figured as interest on the amount you underpaid, running from the day the installment was due until you cover it.2Office of the Law Revision Counsel. 26 USC 6654 – Failure by Individual to Pay Estimated Income Tax Each quarter is judged on its own. A missed April payment keeps accruing interest even if you catch up perfectly on the June, September, and January installments.
To put numbers on it: a $5,000 installment missed by 90 days at a 7% annual rate produces a penalty of roughly $86. Not catastrophic for one slip. The math turns painful if you miss several quarters, owe larger amounts, or let the shortfall sit for most of the year. The IRS also resets the rate each quarter based on the federal short-term rate, so the cost can shift mid-year.1Internal Revenue Service. Quarterly Interest Rates
One trap surprises a lot of filers: getting a refund at tax time does not cancel the penalty. Because the IRS looks at each period separately, you can be owed money at year-end and still owe a penalty for quarters where you paid late or short.
What to Do Right After You Miss One
Pay as soon as you can. Every day the shortfall sits unpaid is another day of interest, so speed matters more than getting the amount perfect. If you can’t cover the full installment, send whatever you can. Partial payments cut the penalty because interest only runs on what’s left outstanding.3Internal Revenue Service. Underpayment of Estimated Tax by Individuals Penalty
Three ways to get the money to the IRS:
- IRS Direct Pay pulls the payment straight from your bank account for free, with no account setup required.4Internal Revenue Service. Direct Pay with Bank Account
- EFTPS is another free federal system, and it lets you schedule payments up to 365 days ahead. Enrollment takes a few business days, so it’s less useful for a same-day fix.5Internal Revenue Service. EFTPS – The Electronic Federal Tax Payment System
- Mailing a check with the correct quarterly voucher from Form 1040-ES works too. Use the voucher that matches the quarter you’re paying.6Internal Revenue Service. Form 1040-ES (2026)
If you overpaid on last year’s return and elected to apply that refund to this year’s estimated tax, the IRS credits the overpayment in the order that best reduces underpayment penalties. Once you’ve made that election on the return, you generally cannot reverse it later.
You can also request a payment plan for a balance you cannot pay all at once. Interest keeps accruing on the unpaid portion until it’s settled, but a plan prevents collection action while you catch up.3Internal Revenue Service. Underpayment of Estimated Tax by Individuals Penalty
The Withholding Trick That Can Undo a Missed Quarter
If you also earn wages or take retirement distributions, increasing your withholding is the strongest catch-up tool available. The IRS treats tax withheld from a paycheck as if it were paid evenly across all four quarters, no matter when in the year the withholding actually happens.7Internal Revenue Service. Publication 505 (2025), Tax Withholding and Estimated Tax Bump up your W-4 withholding in October or November and the extra tax retroactively covers the April, June, and September periods too.
Estimated tax payments don’t work that way. A payment made in September only counts toward Q3 and later; it can’t reach back and cure a missed April installment. If you have a wage job alongside your self-employment or investment income, adjusting withholding is often the cleanest fix once you realize you’re behind.
Safe Harbors That Erase the Penalty
Even after a missed quarter, you may end up owing no penalty at all if your total year’s payments meet one of these tests:3Internal Revenue Service. Underpayment of Estimated Tax by Individuals Penalty
- Your total tax after withholding and refundable credits comes in under $1,000.
- Your combined withholding and estimated payments cover at least 90% of your current-year tax.
- Your payments equal at least 100% of the tax shown on last year’s return, and that return covered a full 12 months.
The 100% rule is the workhorse for self-employed filers because it lets you pay against a known number. It comes with a catch: if your prior-year adjusted gross income was over $150,000 (or $75,000 if you’re married filing separately), you need to pay 110% of last year’s tax instead of 100%.8Internal Revenue Service. Estimated Tax for Individuals
Annualizing Income When Earnings Are Uneven
The standard penalty calculation assumes you earned income evenly across the year. If yours arrived in bursts, say from a seasonal business or a December capital gain, the annualized income installment method can shrink or eliminate the penalty for quarters when you actually had little income to pay tax on. You calculate it using Schedule AI on Form 2210, matching each quarter’s required payment to what you genuinely earned in that period.9Internal Revenue Service. Instructions for Form 2210 (2025)
It’s more paperwork than the default method. Worth it when a big chunk of your income lands late in the year, because otherwise the IRS assumes you should have been paying steady installments from April.
When the IRS Waives the Penalty
Two categories of waiver exist for situations where charging the penalty would be unfair:
- A federally declared disaster, a serious casualty, or another extraordinary event that caused the missed payment.2Office of the Law Revision Counsel. 26 USC 6654 – Failure by Individual to Pay Estimated Income Tax
- Retirement after age 62 or becoming disabled during the tax year or the year before, where the underpayment was due to reasonable cause rather than neglect.2Office of the Law Revision Counsel. 26 USC 6654 – Failure by Individual to Pay Estimated Income Tax
You request a waiver by filing Form 2210 with your return and checking the appropriate box. The IRS decides case by case, so approval isn’t guaranteed, but these waivers exist for exactly the kind of life events they describe.
State Estimated Taxes Are Separate
Paying your federal shortfall does nothing for your state. Most states with an income tax run their own estimated payment system with their own thresholds, deadlines, and underpayment penalties. Some require estimated payments at just a few hundred dollars of expected tax; others set the bar higher. State penalty rates don’t match the federal rate, and the due dates often mirror the federal calendar without being identical. If you missed a federal payment, check whether you missed a state one too, and look up your state department of revenue’s rules for catching up.