Finance calculators

IRS Penalty Calculator

Updated Sep 21, 2026 By Infinity Calculator
Rate Formulas

Quick-Start Scenario

1. Taxpayer & Tax Year Information

Rates loaded.
Drives due dates and entity-specific penalties.
Enter the tax shown as owed on the return — not the amount already paid.

2. Penalty Type Selection

Select Penalty Types to Calculate
i
i
i
i

3. Dates & Filing Status

Auto-filled from entity type and tax year. Edit if your situation differs.
Extension Filed?
If left blank, the return is treated as not yet filed.
All penalties and interest are calculated through this date.
Published quarterly rates (federal short-term + 3%) are used for every segment unless overridden.

4. IRS Notices, Adjustments & Levy

IRS Notice / Demand Sent? i
Notice of Intent to Levy? i
IRS Adjustment?

5. Installment Agreement

Active Installment Agreement? i

6. Payments & Credits

Post-Due-Date Payments

Post-due-date payments reduce the interest-bearing principal starting on the payment date. Failure to Pay is recalculated on the remaining unpaid balance at the end of each penalty period.

Pre-Due-Date Credits & Adjustments

Credits or payments credited on or before the original due date reduce the tax base used for all penalty and interest calculations from day one. Use a negative number to increase the balance (e.g., an amended assessment).

Summary
Tax Year—
Entity Type—
Original Tax Owed—
Failure to File Penalty—
Failure to Pay Penalty—
Accuracy-Related Penalty—
Total Penalties—
Total Interest Accrued—
Total Payments / Credits Applied—
Total Amount Due
$0.00
Step-by-Step Solution
Failure to File — Detailed Breakdown
Failure-to-File penalty accrual by monthly period
Date / PeriodMonths LateRate Applied Unpaid Tax BasePenalty for PeriodIRC CitationExplanation
Failure to Pay — Detailed Breakdown
Failure-to-Pay penalty accrual by monthly period and rate group
Date / PeriodMonths LateRate Applied Unpaid Tax BasePenalty for PeriodIRC CitationExplanation
Accuracy-Related & Entity Penalties
Flat-rate penalties applied once to the tax base
PenaltyTax BaseRatePenalty AmountIRC CitationExplanation
Interest Breakdown (Quarterly Segments)
Daily-compounded interest segmented at every IRS quarterly rate boundary
QuarterStart DateEnd DateDays Annual RateDaily FactorOpening Balance Interest AccruedClosing BalanceCumulative Interest
Full Summary (Tax Professional View)
Component-level summary; interest is allocated pro-rata across components
ComponentAmountInterest (allocated) Credits AppliedNet Balance
Accrual Timeline
Cumulative amount owed — unpaid tax, accrued penalties and accrued interest — from the return due date through the payoff date.
What-If: Compare a Different Payoff Date

Introduction

If you file your tax return late or pay the IRS late, you owe more than just the tax. The IRS adds penalties and interest on top. This IRS Penalty Calculator shows how much you owe today, and how much more you will owe if you wait.

The tool works out the three main charges:

  • Failure to File penalty: 5% of your unpaid tax each month you are late, up to 25% (IRC §6651(a)(1)).
  • Failure to Pay penalty: 0.5% each month, up to 25%. This drops to 0.25% during an installment agreement and rises to 1% after a Notice of Intent to Levy.
  • Interest: charged daily at the IRS quarterly rate, and it builds on your penalties too (IRC §6601 and §6621).

Enter your tax year, the tax you owe, your due date, and the date you plan to pay. You can also add payments you already made, credits, IRS notices, and any IRS adjustment. The calculator handles the rules for individuals, C-corporations, S-corporations, partnerships, LLCs, trusts, and estates, including the extra per-partner and per-shareholder late filing penalties.

You get the total due, a step-by-step math breakdown, month-by-month penalty tables, a daily interest schedule, and a chart of how your balance grows. There is also a "what if" tool so you can compare two payoff dates and see how much money you save by paying sooner.

How to use our IRS Penalty Calculator

Enter your tax year, how much tax you owe, and your key dates. The calculator shows your Failure to File penalty, Failure to Pay penalty, accuracy penalty, daily interest, and the total you must pay.

Quick-Start Scenario: Pick the button that matches your case, like "I haven't filed my return yet." It sets the common options for you. Pick "Advanced / Custom" to start fresh.

Tax Year: Choose the year of the late return. This loads the right IRS rates and penalty amounts.

Taxpayer Entity Type: Pick who files the return, such as an individual, C-corp, S-corp, partnership, LLC, trust, or estate. This sets the due date and any extra penalties.

Number of Partners / Shareholders: Only shows for partnerships and S-corps. Enter how many partners or shareholders you have, since the late-filing penalty is charged per person, per month.

Tax Owed (Per Return): Enter the tax shown as owed on the return. Do not enter what you already paid.

Penalty Types: Check the penalties you want to figure. Failure to File is 5% a month. Failure to Pay is 0.5% a month. Accuracy-Related is a one-time 20%.

QBI Deduction Box: Check this if the understated tax came from the §199A QBI deduction. It lowers the threshold for the accuracy penalty.

Return Due Date: Enter the original due date, before any extension. We fill it in for you based on your entity and year.

Extension Filed: Pick "Yes" if you filed an extension, then enter the new due date. The file penalty starts later, but the pay penalty still starts at the original date.

Date Return Filed: Enter the day you filed. Leave it blank if you have not filed yet.

Payoff Date: Enter the day you plan to pay in full. All penalties and interest are counted through this date.

IRS Underpayment Interest Rate: We use the published IRS quarterly rates. Check the override box only if you want to type your own rate.

IRS Notice / Demand Sent: Pick "Yes" and enter the notice date if the IRS sent you a bill, like a CP14. This is for your records and does not raise the rate.

Notice of Intent to Levy: Pick "Yes" and enter the date if you got a final levy notice. The Failure to Pay rate jumps to 1% a month after that date.

IRS Adjustment: Pick "Yes" if the IRS changed your tax, then enter the date and amount. Use a plus number for more tax and a minus number for less tax. The accuracy penalty needs this amount.

Installment Agreement: Pick "Yes" and enter the start and end date of each payment plan. The Failure to Pay rate drops to 0.25% a month during that time.

Post-Due-Date Payments: Add each payment you made after the due date with its date and amount. These lower the balance that interest grows on.

Pre-Due-Date Credits & Adjustments: Add any credits or payments made on or before the due date. These lower the tax base from day one.

Calculate Penalties & Interest: Click this to see your summary, step-by-step math, month-by-month tables, and a chart of what you owe.

What-If Payoff Date: Enter a different pay date and click recalculate. You will see how much more, or less, you would owe.

IRS Penalties and Interest: What You Need to Know

When you file a tax return late, pay your tax late, or report too little tax, the IRS adds charges on top of what you owe. These charges are called penalties. On top of that, the IRS charges interest on your unpaid balance. Both grow the longer you wait, so a small tax bill can turn into a much bigger one.

Failure to File Penalty

This penalty applies when your return is late. It is 5% of the unpaid tax for each month or part of a month the return is late. It stops at 25%. If your return is more than 60 days late, a minimum penalty kicks in. That minimum is a set dollar amount (it changes each year) or 100% of the tax you owe, whichever is smaller. This rule comes from IRC §6651(a)(1).

Failure to Pay Penalty

This one applies when you do not pay the tax by the due date, even if you filed on time. It is 0.5% of the unpaid tax each month, up to 25%. The rate can change:

  • 0.25% per month while you have an active installment agreement (a payment plan).
  • 1% per month after the IRS sends a Final Notice of Intent to Levy.

A normal bill in the mail, like a CP14 notice, does not raise the rate. Only a levy notice or a demand for immediate payment does.

When Both Penalties Apply

If you file late and pay late in the same month, the two penalties do not simply stack. The 5% file penalty is cut by the 0.5% pay penalty for that month. So you pay 5% total per month, not 5.5%. This coordination rule is in IRC §6651(c).

Accuracy-Related Penalty

If the IRS finds you reported too little tax because of carelessness or a big mistake, it can add a one-time 20% penalty on the extra tax. This usually needs a "substantial understatement," meaning more than 10% of your correct tax or $5,000, whichever is larger. If you claimed the §199A QBI deduction, that line drops to 5%.

Partnership and S-Corp Penalties

Partnerships and S-corporations face a different late-filing penalty. It is a flat dollar amount per partner or shareholder, for each month late, for up to 12 months. This applies even if the business owes no tax.

Interest

Interest is separate from penalties. The IRS sets a rate every three months: the federal short-term rate plus 3%. Interest compounds daily, meaning you pay interest on your interest. It also builds on unpaid penalties, not just unpaid tax. Interest starts on the original due date and runs until you pay in full. An extension to file does not stop it.

How to Lower What You Owe

  • File on time, even if you cannot pay. The late-file penalty is 10 times bigger than the late-pay penalty.
  • Pay something. Every dollar you pay shrinks the base that penalties and interest grow on.
  • Set up a payment plan. It cuts the late-pay rate in half.
  • Ask for First-Time Abatement. If you have a clean record for the past three years, the IRS may drop the penalties.
  • Show reasonable cause. Serious illness, disaster, or records lost through no fault of yours can qualify for relief.

Penalty relief can remove penalties, but interest on the tax itself almost never goes away. Interest tied to a removed penalty is removed too.

Formulas used

Tax Base After Pre-Due-Date Credits
B = T_{\text{owed}} - C_{\text{pre}} + A_{\text{pre}}
Failure to File Penalty (monthly accrual, net of FTP offset)
\text{FTF} = \sum_{i=1}^{n} B \times \frac{\max\left(0,\; \min(5\%,\; 25\% - G_{i-1}) - r^{\text{FTP}}_i\right)}{1}
Minimum Failure to File Penalty (return more than 60 days late)
\text{FTF} = \max\left(\text{FTF},\; \min\left(M_{\text{year}},\; B\right)\right)
Failure to Pay Penalty (monthly accrual, capped at 25%)
\text{FTP} = \sum_{i=1}^{m} B_i \times \min\left(r_i,\; 25\% - \textstyle\sum_{j
Accuracy-Related Penalty (IRC 6662)
\text{ARP} = \begin{cases} 0.20 \times A & A > \max\left(p \times T_{\text{owed}},\; 5000\right) \\ 0 & \text{otherwise} \end{cases},\quad p = \begin{cases} 0.05 & \text{QBI} \\ 0.10 & \text{else} \end{cases}
Per-Partner / Per-Shareholder Late Filing Penalty
P = a_{\text{year}} \times N_{\text{partners}} \times \min\left(\text{months late},\; 12\right)
Daily-Compounded Interest (IRC 6601/6621/6622)
I = \sum_{d=1}^{D} \left(B_d + P_d + I_{d-1}\right) \times \frac{r_d}{365 \text{ or } 366}
Total Amount Due at Payoff Date
\text{Total} = B_{\text{tax}} + B_{\text{penalties}} + I

Frequently asked questions

How much is the IRS penalty for filing taxes late?

The late filing penalty is 5% of your unpaid tax for each month or part of a month your return is late. It stops at 25%, which you hit after 5 months.

Example: you owe $10,000 and file 3 months late. The penalty is $10,000 × 5% × 3 = $1,500.

Even one day into a new month counts as a whole month.

What is the minimum IRS penalty for filing more than 60 days late?

If your return is over 60 days late, you pay a minimum penalty. It is the smaller of a set dollar amount or 100% of the tax you owe.

  • 2023 returns: $485
  • 2024 returns: $510
  • 2025 returns: $525

So if you owe $300 and file 8 months late, your penalty is $300, not $525. You never pay more than the tax itself under this rule.

Do IRS penalties and interest stack on top of each other?

Yes, but not the way most people think.

  • Failure to File and Failure to Pay: These do not fully stack. In months when both apply, the 5% file penalty is cut by the 0.5% pay penalty. You pay 5% total, not 5.5% (IRC §6651(c)).
  • Interest: This does stack. Interest is charged on unpaid tax and on unpaid penalties.

So your penalties grow your balance, and then interest grows on that bigger balance.

Does filing an extension stop IRS penalties and interest?

An extension stops only the late filing penalty. It does not stop the late payment penalty or interest.

An extension gives you more time to file paperwork, not more time to pay. If you owe tax on April 15 and pay in October, the 0.5% monthly pay penalty and daily interest both run the whole time.

Tip: pay your best guess by the original due date, even with an extension.

What is the IRS interest rate on unpaid taxes right now?

For 2025 and into 2026, the underpayment rate is 7% per year for individuals.

The IRS sets this rate every three months. It equals the federal short-term rate plus 3 percentage points. Recent rates:

  • 2021: 3%
  • 2022: 3% to 6%
  • 2023: 7% to 8%
  • 2024: 8%
  • 2025: 7%

The rate is locked in for each quarter, so a long-running balance may cross several different rates.

How does the IRS calculate daily compound interest on back taxes?

The IRS divides the yearly rate by the number of days in the year, then charges that tiny amount each day on your whole balance.

At 7% in a 365-day year, the daily factor is 0.07 ÷ 365 = 0.00019178.

On a $20,000 balance, that is about $3.84 the first day. The next day, interest is charged on $20,003.84. This is why the bill grows faster over time (IRC §6622).

Is it better to file on time and not pay, or wait until I can pay?

Always file on time. The late filing penalty is 10 times bigger than the late payment penalty.

On $10,000 owed for 5 months:

  • Filed late and unpaid: about $2,500
  • Filed on time, paid late: about $250

Filing on time saves roughly $2,250 in this example. File the return even with $0 attached.

Does a payment plan reduce IRS penalties?

Yes. While an installment agreement is active, the Failure to Pay penalty drops from 0.5% to 0.25% per month (IRC §6651(h)).

That cuts the pay penalty in half. Interest does not change, and it still compounds daily.

You must have filed all required returns for the lower rate to apply.

When does the IRS charge 1% per month instead of 0.5%?

The rate doubles to 1% per month only after the IRS sends a Final Notice of Intent to Levy and you do not pay within 10 days.

A regular bill, like a CP14 notice, does not raise the rate. Many people think it does. Under IRC §6651(d), only a levy notice or a demand for immediate payment triggers the higher rate.

How do I get IRS penalties removed or waived?

There are three main ways:

  • First-Time Abatement: If you had no penalties for the past 3 years and filed all returns, the IRS often removes them. Just call and ask.
  • Reasonable cause: Serious illness, death in the family, a natural disaster, or lost records can qualify. Send proof.
  • Statutory exception: If you relied on wrong written advice from the IRS.

Interest on the tax itself is almost never removed. But interest tied to a removed penalty goes away with it.

What is the penalty for filing a partnership return late?

Partnerships pay a flat penalty per partner, per month, up to 12 months (IRC §6698). It applies even if the partnership owes no tax.

For 2024 and 2025 returns, the amount is $245 per partner per month.

Example: 4 partners, 3 months late = $245 × 4 × 3 = $2,940.

S-corporations face the same kind of penalty per shareholder under IRC §6699.

What triggers the 20% accuracy-related penalty?

The IRS can add a one-time 20% penalty on the extra tax when you report too little (IRC §6662). Common triggers:

  • Substantial understatement: the shortfall is more than 10% of your correct tax, or more than $5,000, whichever is larger.
  • Negligence: careless record-keeping or ignoring clear rules.

If you claimed the §199A QBI deduction, the threshold drops to 5%. The 20% rate stays the same.

This penalty is charged once. It does not build each month.

When are business tax returns due?

For calendar-year filers:

  • S-corporations and partnerships: March 15
  • C-corporations: April 15
  • Individuals and most LLCs: April 15
  • Trusts and estates: April 15

If the date falls on a weekend or holiday, it moves to the next business day. Extensions add 6 months for most filers, but only 5.5 months for trusts and estates (Form 1041 goes to September 30).

Do payments I make after the due date lower my late filing penalty?

No. Under IRC §6651(b)(1), the late filing penalty is based on the tax unpaid as of the original due date. Money you send later does not shrink that base.

Payments made after the due date do lower your Failure to Pay penalty and your daily interest going forward.

This is why paying something before the deadline helps more than paying the same amount a month later.

How long can the IRS charge penalties and interest?

The two penalties have caps, but interest does not.

  • Failure to File: stops at 25% (about 5 months).
  • Failure to Pay: stops at 25% (about 50 months).
  • Interest: runs every day until the balance hits zero.

The IRS generally has 10 years to collect from the assessment date. Interest keeps building that whole time, so an old balance can end up larger than the original tax.

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