IRS Penalty and Interest Calculator
Estimate failure-to-file penalty, failure-to-pay penalty, daily IRS underpayment interest, the payment-plan rate, and the 2026 minimum late-filing penalty.
Last Updated: May 2026
IRS penalty estimate
Estimate late-filing, late-payment, and interest charges
Enter the unpaid tax, filing date, payment date, and IRS rate assumption. The calculator separates failure-to-file penalty, failure-to-pay penalty, and daily-compounded interest so you can audit the main moving pieces before checking an IRS notice.
Rule Snapshot: May 2026
Failure-to-file is generally 5% of unpaid tax per month or partial month, up to 25%, reduced by failure-to-pay when both apply. Failure-to-pay is generally 0.5% per month or partial month, up to 25%; approved individual payment plans may use 0.25%, and levy-notice cases may use 1%. IRS Q2 2026 standard underpayment interest rate is 6% per year, compounded daily.
Balance and Date Inputs
Tax still unpaid after timely payments and refundable credits.
Use the original due date unless you are modeling a valid filing extension.
The failure-to-file estimate stops on this date.
Usually the original return due date; filing extensions do not extend payment.
The failure-to-pay and interest estimates stop here.
Penalty and Interest Assumptions
Regular rate for unpaid tax shown on a return or assessed by notice.
IRS underpayment rate for corporate and non-corporate underpayments for Apr-Jun 2026.
Used only when the interest-rate preset is set to custom.
Default is $525 for Forms 1040/1120 due after Dec. 31, 2025.
IRS Penalty Estimate Notice
This calculator is a planning and notice-checking estimate. It does not replace an IRS transcript, IRS bill, filing software, attorney, CPA, enrolled agent, or final penalty relief decision.
Reviewed For Methodology, Labels, And Sources
Every CalculatorWallah calculator is published with visible update labeling, linked source references, and review of formula clarity on trust-sensitive topics. Use results as planning support, then verify institution-, policy-, or jurisdiction-specific rules where they apply.
Reviewed by Iliyas Khan, Chief Operating Officer. Page updated May 2026. Tax, sales tax, insurance, and health calculators are reviewed when rules, rates, eligibility assumptions, healthcare standards, or source references change. Topic ownership: Tax calculators, Sales tax calculators, Insurance calculators, Health calculators.
Tax credentialed review: Named internal reviewer: Iliyas Khan, Chief Operating Officer. External credentialed professional review is still required before this page is treated as professional advice.
Internal tax and sales-tax methodology reviewer. Review scope: calculator assumptions, labels, source context, workflow clarity, and compliance-sensitive disclaimers.
Relevant review context: CalculatorWallah tax and sales-tax calculator workflow owner; Source-first review of IRS, state revenue, rate, and filing-sensitive references; Compliance-sensitive labels, assumptions, and user-facing disclaimer review.
Required professional credentials: CPA, Enrolled Agent, licensed tax professional. Scope: tax formulas, jurisdiction assumptions, withholding language, filing-sensitive examples, and compliance caveats.
This page is educational planning support. A named CPA, EA, or licensed tax professional should review the page before it is positioned as tax advice or used for filing decisions.
Source expectation: Review should cite current IRS, state revenue department, payroll-tax, or official tax authority sources where applicable.
Use the IRS Penalty Calculator for the Right Question
Use the scope guide below before you calculate. Several GPA and conversion tools sound similar, but they start from different inputs and solve different transcript problems.
Use this page when
- You filed a return late and want to separate failure-to-file from failure-to-pay.
- You filed on time but paid late and need a quick FTP plus interest estimate.
- You want to compare regular, payment-plan, and levy-notice failure-to-pay assumptions.
- You are checking whether the more-than-60-days minimum filing penalty may matter.
Use another tool when
- You need a filed return, IRS transcript reconciliation, or final collection balance.
- You are calculating the estimated tax underpayment penalty for missed quarterly payments.
- You are calculating payroll deposit, information return, FBAR, or state tax penalties.
Closest Alternatives
Step 1: Enter the unpaid tax balance
Use the tax still unpaid after timely payments, withholding, estimated payments, and refundable credits.
Step 2: Enter filing and payment dates
Use the return due date, actual filing date, payment due date, and planned full-payment date.
Step 3: Choose the failure-to-pay mode
Select the regular monthly penalty rate, approved individual payment-plan rate, or levy-notice rate.
Step 4: Choose the IRS interest rate
Use the quarter that covers the unpaid period or enter a custom annual IRS rate when the period spans another quarter.
Step 5: Review the penalty trace
Check failure-to-file, failure-to-pay, daily interest, minimum penalty, and month-by-month rows separately.
How the IRS Penalty and Interest Calculator Works
The calculator estimates three separate layers: failure-to-file penalty, failure-to-pay penalty, and interest on unpaid tax. Keeping those layers separate matters because each has a different rate, cap, stop date, and relief path.
| Step | Formula used | Important note |
|---|---|---|
| Failure-to-file months | Each month or partial month from return due date to filed date | Percentage penalty usually stops after 5 months. |
| Failure-to-file penalty | Unpaid tax x monthly FTF rate, capped at 25% | When FTF and FTP apply together, FTF is reduced by the FTP rate for that month. |
| Minimum FTF check | Greater of percentage FTF or the limited minimum penalty | For Forms 1040 and 1120 due after December 31, 2025, the minimum failure-to-file penalty after more than 60 days is $525 or 100% of unpaid tax, whichever is less. |
| Failure-to-pay penalty | Unpaid tax x monthly FTP rate x late-payment months, capped at 25% | Regular 0.5%, payment-plan 0.25%, or levy-notice 1% mode. |
| Daily interest | Unpaid tax x ((1 + annual rate / 365) ^ days late - 1) | IRS interest rates are quarterly and compound daily. |
The estimate uses the unpaid tax amount as the base. If the IRS later applies payments, credits, abatement, or quarter-specific interest changes differently, the official notice can differ from this planning number.
IRS Late Filing, Late Payment, and Interest Rules
Which Dates Should You Enter?
For a normal individual balance due, the payment due date is usually the original April filing deadline. A filing extension can change the return due date for the failure-to-file penalty, but it generally does not move the payment due date. That is why the calculator asks for both dates instead of assuming they are always the same.
| Scenario | How to enter it | Why |
|---|---|---|
| Late return with balance due | Use return due date, filed date, payment due date, and paid date. | Shows both late-filing and late-payment layers. |
| Filed on time but paid late | Set filed date equal to due date and payment date later. | Failure-to-file should be zero, but FTP and interest can continue. |
| Valid filing extension | Use the extended filing due date for return due date, but keep payment due date at the original deadline. | An extension to file generally does not extend time to pay. |
| Payment plan estimate | Choose the approved individual payment-plan mode only when the return was filed on time and the plan qualifies. | The reduced FTP rate is not automatic for every late balance. |
Failure-to-File vs Failure-to-Pay
The failure-to-file penalty is usually the larger charge, so filing as soon as possible can matter even if the balance cannot be paid immediately. When both penalties apply in the same month, the calculator reduces the failure-to-file monthly rate by the selected failure-to-pay rate, matching the IRS interaction described in its penalty guidance.
For deeper background, use the failure-to-file vs failure-to-pay guide and the separate IRS late filing penalty guide.
IRS Interest Rate Assumptions
IRS interest rates are set quarterly and compound daily. This page defaults to the standard Q2 2026 underpayment rate because it covers April through June 2026 planning, but the custom rate field is available when a balance spans a different quarter.
| Preset | Annual rate | When to use |
|---|---|---|
| Q2 2026 standard underpayment | 6% | Default for April through June 2026 planning. |
| Q1 2026 standard underpayment | 7% | Useful for January through March 2026 scenarios. |
| Q2 2026 large corporate underpayment | 8% | Use only for large corporate underpayment scenarios. |
| Custom rate | User-entered | Use when the period spans a different IRS quarterly rate. |
What This Calculator Does Not Include
IRS penalty notices can involve multiple tax periods, posted payments, amended return timing, abatements, and assessed penalty interest. This tool keeps the model transparent by focusing on the common late filing, late payment, and unpaid-tax interest layers.
| Item | Treatment |
|---|---|
| Estimated tax underpayment penalty | Not included. Use Form 2210-style period rules for missed quarterly estimates. |
| Interest on assessed penalties | Not included because assessment dates vary by account, notice, and abatement history. |
| Penalty relief | The calculator estimates charges before relief. First Time Abate and reasonable-cause relief require separate eligibility review. |
| Exact IRS account transcript math | IRS notices can reflect payments, credits, prior assessments, abatements, and quarter-by-quarter rate changes not entered here. |
After You Estimate the Charge
If the estimate looks material, compare it with the IRS notice line by line: unpaid tax base, penalty type, tax period, assessment date, payment date, and interest rate. Then check whether penalty relief may apply. The First-Time Penalty Abatement Guide explains the clean-compliance path, while How to Reduce IRS Penalties covers broader relief, payment-plan, and dispute workflows.
Keep the research moving with Tax Refund Calculator 2026, Taxable Income Calculator, Federal Income Tax Calculator, and Self Employment Tax Calculator.
Frequently Asked Questions
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- 1.IRS - Failure to File Penalty(Accessed May 2026)
- 2.IRS - Failure to Pay Penalty(Accessed May 2026)
- 3.IRS - Quarterly Interest Rates(Accessed May 2026)
- 4.IRS - Interest(Accessed May 2026)
- 5.IRS - Penalty Relief(Accessed May 2026)