You owe $10,000 in tax you cannot pay right now, so you do nothing — no return, no payment, no deposit. Six months later the IRS bill is not $10,000. It is $12,750 plus interest, because the penalty for not filing the paperwork ran ten times hotter than the penalty for not paying. The cruelest part: filing the return on time, even with no payment enclosed, would have cut the damage by two-thirds. This guide walks through all three penalties — failure to file, failure to pay, and the payroll-only failure to deposit — how they combine, what relief exists, and the bookkeeping setup that keeps you from ever meeting them.
The Three Penalties in Sixty Seconds
All three penalties punish different failures, run on different clocks, and come from different code sections. Here is the whole map before the detail:
| Penalty | Punishes | Rate | Cap | Code section |
|---|---|---|---|---|
| Failure to file | Return filed late | 5% of unpaid tax per month or part of a month | 25% | 6651(a)(1) |
| Failure to pay | Tax paid late | 0.5% of unpaid tax per month or part of a month | 25% | 6651(a)(2) |
| Failure to deposit | Payroll deposits made late | 2%, 5%, 10%, or 15% of the late deposit, by days late | One tier applies, not stacked | 6656 |
Two facts shape everything else. First, the file and pay penalties are percentages of unpaid tax, so a return that claims a refund faces neither — there is nothing to take a percentage of. Second, an extension of time to file is never an extension of time to pay: Form 4868 or 7004 moves your paperwork deadline, while the payment clock started on the original due date regardless.
Failure to File: 5% a Month, the One That Hurts Most
The failure-to-file penalty runs at 5% of the unpaid tax for each month or part of a month the return is late, up to 25% — which means it maxes out after just five months. A single day late counts as a full month. Owe $10,000 and file three months late, and the penalty is $1,500 before interest enters the picture.
File more than 60 days late and a floor kicks in: the minimum penalty is the smaller of a flat dollar amount or 100% of the unpaid tax. That flat amount adjusts for inflation — $510 for returns due in 2025, $525 for returns due in 2026. On small balances the floor is the whole story: owe $200 and file three months late, and the penalty is the full $200, not 15% of it.
The refund exception is worth stating plainly. Because the penalty is a percentage of tax you failed to pay with a timely return, a return owed a refund accrues no failure-to-file penalty at all. That is not permission to ignore the deadline — you generally have three years from the due date to file and still claim the refund, after which it becomes the government's — but it means a late refund return is a missed payday for you, not a growing bill.
This penalty also reaches payroll returns. A late Form 941 draws the same 5%-per-month treatment on the unpaid employment tax shown on the return, which is how one bad quarter as an employer can produce both a filing penalty and the deposit penalty below on overlapping dollars.
Failure to Pay: 0.5% a Month, Slow but Relentless
The failure-to-pay penalty accrues at 0.5% of the unpaid tax per month or part of a month, also capped at 25% — but at one-tenth the monthly rate, it takes 50 months to reach the ceiling. The same $10,000 paid three months late costs $150 in penalties instead of $1,500. That ten-to-one ratio is the single most useful number in this guide: when you cannot do both, file first and pay later.
The rate is not fixed for life. It moves in both directions:
- Down to 0.25% per month for any month an installment agreement is in effect, provided you filed the return on time. Setting up a payment plan literally halves the bleeding.
- Up to 1% per month if the tax remains unpaid 10 days after the IRS issues a notice of intent to levy. Ignore the certified mail and the slow penalty doubles.
Payments are applied to the tax first, then to penalties, then to interest — an ordering that matters because every dollar that retires tax principal also shrinks the base the monthly penalties accrue on. Partial payments are never wasted.
How the Two 6651 Penalties Combine
When both penalties run in the same month, the IRS reduces the failure-to-file portion by the failure-to-pay portion, so the combined rate is 5% per month rather than 5.5%: 4.5% for not filing plus 0.5% for not paying. After five months the filing penalty hits its 25% cap (reduced to 22.5% by the overlap), and the 0.5% payment penalty continues alone until it reaches its own 25%. The worst case — never filing and never paying for years — totals 47.5% of the unpaid tax in penalties alone, before interest.
A worked example makes the file-anyway lesson concrete. You owe $10,000, due April 15, and you can neither file nor pay until October 15 — six months late on both:
- Failure to file: 4.5% × 5 months (capped) = 22.5% = $2,250
- Failure to pay: 0.5% × 6 months = 3% = $300
- Total penalties: $2,550, plus six months of interest
Now the alternative: you file on April 15 with no payment and pay October 15. The filing penalty is zero. The payment penalty is the same $300. Same debt, same delay, $2,250 less in penalties — for the price of filing a return that says what you owe.
Failure to Deposit: The Payroll-Only Penalty With Tiers
Employers do not simply pay employment tax with the return; they deposit withheld income tax and FICA taxes through EFTPS on a monthly or semiweekly schedule during the quarter, then reconcile on Form 941. Miss a deposit deadline and the failure-to-deposit penalty under section 6656 applies — on a clock measured in days, not months:
| Days late | Penalty on the late deposit |
|---|---|
| 1–5 calendar days | 2% |
| 6–15 calendar days | 5% |
| More than 15 calendar days | 10% |
| Unpaid more than 10 days after the first IRS delinquency notice, or on receipt of an immediate-payment notice | 15% |
The tiers replace each other; they never stack. A deposit 12 days late costs 5%, not 2% plus 5%. A deposit that sits unpaid past the first IRS notice jumps to 15% of that deposit. Because the penalty attaches per deposit period, a quarter of missed semiweekly deposits produces a separate penalty computation for each missed deadline — the amounts add up fast even though the tiers do not.
Three traps catch small employers specifically. First, the deposit schedule — monthly or semiweekly — is set by a lookback period measuring how much employment tax you reported, and growing payrolls graduate to semiweekly without anyone sending a congratulations card. Second, EFTPS deposits must generally be initiated by 8 p.m. Eastern the day before the due date, so a deposit you "make" on the deadline is already a day late. Third, depositing is not filing: timely deposits with a late 941 still draw the 5%-a-month filing penalty on any balance due with the return, and a timely return with late deposits still draws the 6656 tiers.
Behind all of this sits the penalty that makes payroll tax uniquely dangerous. Withheld taxes are trust fund taxes — money you hold as the government's collection agent — and the people responsible for collecting and paying them can be assessed 100% of the unpaid trust fund amount personally under section 6672, the trust fund recovery penalty. Owners, officers, and anyone with check-signing authority over payroll are in scope. Deposit penalties are expensive; the personal liability behind them is why payroll tax problems get professional help first and payment-plan treatment second.
Interest: The Fourth Charge Nobody Caps
Interest accrues on unpaid tax from the due date until paid, compounded daily at the federal short-term rate plus 3 percentage points, reset quarterly. It also accrues on the penalties themselves once assessed. Unlike the penalties, interest has no cap, no abatement program, and no mercy rule — by law the IRS cannot remove interest unless the underlying penalty or tax is removed. Every month of delay therefore costs both the penalty rate and the going interest rate, which is why stopping the 5% filing penalty by filing immediately is the highest-return paperwork you will ever do.
Getting Penalties Removed: First-Time Abatement and Reasonable Cause
Two doors lead out of penalties already assessed, and you should check them in order.
First-time abatement is an administrative waiver, not a legal argument. You qualify if you had no penalties in the three prior tax years, have filed all currently required returns (or valid extensions), and have paid or arranged to pay the tax due. One clean-history taxpayer gets one tax period of failure-to-file, failure-to-pay, or failure-to-deposit penalties wiped with no explanation required — a phone call to the IRS can do it. Save reasonable cause for a year that needs it, because abatement under this policy spends your clean record.
Reasonable cause covers failures caused by circumstances beyond your control despite ordinary business care: serious illness, a natural disaster, destroyed records, erroneous written IRS advice you relied on. It requires a written case — Form 843, Claim for Refund and Request for Abatement, with documentation — and a judgment call by the IRS. Know what does not qualify: lack of funds alone is never reasonable cause, and relying on an accountant or payroll provider generally is not either unless you can show you gave them everything on time and they failed you.
If the penalties stand, an installment agreement still drops the failure-to-pay rate to 0.25% while it runs, and partial payments always attack the tax principal first. Relief denied is not the end of the math working in your favor.
The Bookkeeping That Keeps You Out of This
Penalties are a calendar problem wearing a money costume, so the fix is equal parts scheduling and ledger hygiene. Put every deposit date and return due date on a calendar with two alerts — one a week out, one the business day before — and reconcile EFTPS confirmations to your books the way you reconcile bank statements. If payroll has grown, verify your deposit schedule at the start of each year rather than discovering mid-quarter that you graduated to semiweekly.
In the ledger, give penalties their own account and never mingle them with deductible tax expense: IRS penalties are not deductible business expenses, and burying a $420 deposit penalty in your payroll tax account overstates deductions while hiding the leak. A plain-text ledger makes the separation explicit:
2026-04-15 * "IRS" "Q1 payroll tax deposit via EFTPS"
Liabilities:Payroll-Taxes-Payable:Federal -8,400.00 USD
Assets:Checking 8,400.00 USD
2026-05-20 * "IRS" "Failure-to-deposit penalty, 8 days late, 5% tier"
Expenses:Tax:Penalties-Nondeductible 420.00 USD
Assets:Checking -420.00 USDThe second transaction tells the whole story at tax time: what the penalty was, why it happened, and — via the account name — that it stays out of deductions. Review that account quarterly in Fava; any quarter it is nonzero is a process failure to fix, not a cost of doing business to accept. The docs walk through setting up payroll and tax accounts like these from scratch.
What to Do This Week
Pull your transcript or your last IRS notice and sort what you owe into the three buckets: unfiled returns, unpaid tax on filed returns, and late payroll deposits. File every unfiled return immediately — even a return you cannot pay stops the 5% clock the day it posts. Then check first-time abatement eligibility before building a reasonable-cause case, set up an installment agreement to halve the payment penalty while you pay down the balance, and put the deposit calendar above in place so next quarter's payroll never joins the list. The IRS charges 5% a month for silence and 0.5% for an honest shortfall; the cheapest sentence in the tax code is the one where you tell them what you owe.
