IRS interest on unpaid tax: check the charge and the period
The standard IRS underpayment interest rate is 7% per year for October through December 2026, compounded daily. It is an annual rate, not a monthly penalty. The correct review starts with the type of charge, the period it covers and the payments or adjustments recorded on the account.
A payment plan does not stop interest on the amount left unpaid. Equally, an increase in a bill does not establish that every charge is correct. Separate the underlying tax, each penalty and interest before deciding what needs to be paid, corrected or reviewed.
Match the rate to its quarter and category
The IRS quarterly interest-rate table publishes separate categories for underpayments and overpayments. Its standard underpayment category has these annual rates for 2026, as checked on November 13:
If the table is clipped, scroll sideways. Use arrow keys when focused.
| Period in 2026 | Standard annual underpayment rate |
|---|---|
| January 1 to March 31 | 7% |
| April 1 to June 30 | 6% |
| July 1 to September 30 | 7% |
| October 1 to December 31 | 7% |
The rate changes do not reprice interest for earlier quarters. If the balance spans several quarters, today’s rate alone does not explain the full interest charge. Daily compounding also means interest can accrue on earlier interest, rather than only on the original tax.
The IRS lists a separate large-corporate-underpayment category. An individual’s balance exceeding $100,000 does not make it a large corporate underpayment. Check the applicable category and period instead of selecting a rate from the amount alone.
The rate the IRS pays on an overpayment answers a different question. So do loan-related applicable federal rates. An estimated-tax underpayment penalty may also use published quarterly rates, but it has its own calculation and Form 2210-related rules. Do not substitute a general unpaid-balance calculation for those procedures.
Identify when each part of the balance began accruing interest
The IRS interest guidance explains that interest generally runs from the due date of the unpaid amount until the balance is paid in full. An ordinary extension to file a return does not extend the time to pay the tax. Establish the actual payment due date, including any applicable postponement, rather than assuming the filing-extension date controls.
Interest start dates for penalties can differ by penalty type. Tax, a failure-to-file penalty and a later billed penalty should not automatically be assigned the same start date. Identify the component and its applicable rule before questioning the period used.
Keep the original tax due date separate from a later bill’s pay-by date. Follow the notice instructions for the amount shown. If the amount or intended payment date has changed, confirm the current account amount rather than treating an old bill as a current payoff quote.
Make a dated account-event record
Use the notice and your own records to organize the issue. This worksheet is a way to prepare for an account review, not an interest calculator.
If the table is clipped, scroll sideways. Use arrow keys when focused.
| Record | What to establish |
|---|---|
| Taxpayer and period | Which individual or entity, tax type and tax year the charge concerns |
| Components | The tax, each penalty and interest shown separately |
| Due-date basis | The payment deadline or penalty-specific starting rule, with any applicable extension or postponement distinguished |
| Notice | Its date, amount, pay-by date and response instructions |
| Payments and credits | Dated confirmations, amounts, intended periods and how the IRS recorded them |
| Account changes | A corrected assessment, reduced penalty or other adjustment, including its date and affected amount |
| Quarters crossed | The periods during which the relevant amount remained unpaid and the corresponding published rate category |
| Question and outcome | The particular charge being questioned, evidence supplied and the later account adjustment or decision |
For example, proof that you made a payment raises a different issue from proof that the IRS reduced a penalty. In the first case, establish whether the payment was credited to the correct account and period. In the second, check whether the related interest was adjusted. An unexplained difference should lead to a specific question, not an assumed waiver of the entire bill.
If the bill itself appears wrong, compare a CP14 balance with payment records where that is the notice you received. For another document, identify the actual IRS notice and response before selecting a procedure.
Choose the review basis that fits the record
If the table is clipped, scroll sideways. Use arrow keys when focused.
| What the evidence shows | Issue to pursue | Keep the request specific |
|---|---|---|
| A payment, credit or underlying tax amount may be wrong | Reconciliation or correction under the relevant account or notice procedure | Identify the affected amount, period and supporting record; do not assume every correction uses Form 843 |
| Tax or a penalty was reduced | Adjustment of interest related to that reduction | Compare the later account figures with the actual change, rather than deleting all interest from an old total |
| A qualifying IRS error or delay caused additional interest | A potentially applicable interest-abatement request | Identify the IRS act, affected liability and period, and the conditions for that particular relief |
| The amount is correct but remains unpaid | Payment of the balance or a suitable arrangement | A payment-plan request concerns how to pay; it does not itself eliminate continuing interest |
The IRS says it automatically reduces related interest when the underlying tax or penalty is reduced. That is different from a standalone request to excuse interest because payment was difficult. The IRS does not remove interest simply as first-time relief or for reasonable cause. The penalty-relief guide addresses those penalty-specific questions.
Check the limits on an IRS error or delay request
Relief under section 6404(e)(1) is narrower than showing that an IRS matter took a long time. The current interest-abatement explanation and Form 843 instructions describe conditions involving an unreasonable error or delay in a ministerial or managerial act.
A ministerial act is a procedural or mechanical step after its prerequisites have been completed. A managerial act can concern matters such as records or management of personnel during a case. A decision about the proper application of tax law is not one of those acts. A general administrative delay is not enough by itself.
The relevant error or delay must occur after the IRS contacted you in writing about an examination, underpayment or payment. The Form 843 instructions also say the taxpayer cannot have caused a significant aspect of the error or delay. Keep correspondence and dated events that allow those conditions to be assessed; a general statement that the process was slow does not establish them.
This provision applies to specified taxes, including income, estate, gift and certain excise taxes. It does not authorize abatement of employment-tax interest under this route. The type of tax matters, not simply whether the taxpayer operates a business.
Only interest attributable to the qualifying period and liability is at issue. The IRS gives an example distinguishing an audit’s additional liability from tax that was already unpaid on the original return. A delay concerning the audit does not, by itself, remove interest on that original unpaid liability.
Follow the applicable request instructions and check the result
For a qualifying IRS error or delay request, the IRS describes Form 843 or a signed letter with a detailed explanation and supporting documents. Follow the current instructions for the actual request, including the relevant tax, period, dates, signature, destination and filing limits. This guide does not calculate a personal claim deadline from the date on a bill.
Form 843 is not a universal way to amend an income-tax return, correct an employment-tax return or dispute every account amount. The form instructions distinguish those tasks. This guide’s section 6404(e)(1) discussion also does not catalogue every other statutory interest issue or claim.
Retain the submission and the IRS response separately. Check which amount and period the decision addresses and what the later account figures show. A submitted request is not evidence that interest was removed. If the request is denied, read the decision’s applicable review instructions promptly.
Any remaining correct balance still needs attention. IRS payment-plan requirements cover arrangements for paying over time. Interest can continue on unpaid amounts during an agreement, so a scheduled payment and a final payoff are different records. Keep any notice response or hearing requirement separate from an interest inquiry.
Sources and scope
- IRS quarterly interest rates: current and historical categories, quarterly changes and daily compounding.
- IRS interest: starting dates, continuing charges, related adjustments and requests.
- IRS interest abatement: conditions and limits for an unreasonable IRS error or delay.
- Current Form 843 instructions: request scope, supporting information and procedures that require another form.
- Estimated-tax underpayment penalty: a separate issue from ordinary interest on an unpaid balance.
Checked November 13, 2026. Rates depend on the quarter and category. This guide does not calculate a payoff, determine personal eligibility or promise interest relief.