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Updated: June 19, 2026 – Most Americans do not know this rule exists. If the IRS took longer than 45 days to process your 2025 federal tax return refund, the agency is legally required to pay you interest on the delayed amount. This is not optional. It is not a courtesy. It is a statutory obligation written into the Internal Revenue Code, and it applies to every individual taxpayer whose refund cleared the 45-day threshold in the 2026 filing season.
For the 2026 filing season, covering tax year 2025 income due April 15, 2026, the 45-day interest-free window closed on May 30, 2026. Any refund the IRS issued after that date must include retroactive interest calculated back to April 15, compounded daily at the official quarterly rate.
The Exact Legal Authority
The IRS interest obligation on delayed refunds is codified in Internal Revenue Code Section 6621. This statute establishes the methodology for calculating the federal short-term rate, sets the overpayment rate for individual taxpayers as the short-term rate plus three percentage points, and mandates daily compounding. There is no administrative discretion. If your refund crossed the 45-day threshold, the IRS owes interest. Full stop.
The IRS legal code Section 6621 overpayment rules explain the exact calculation framework and the quarterly adjustment cycle that determines each period’s specific rate. Taxpayers can verify their entitlement by matching their IRS refund date, visible in the IRS Where’s My Refund portal, against the May 30 threshold date.
The IRS section 6621 overpayment interest article on Investozora provides a detailed breakdown of how the federal short-term rate feeds into the overpayment rate formula, with the quarterly rate history from 2020 through Q2 2026.
The 2026 Interest Rate Is 6%
According to Internal Revenue Bulletin 2026-8, the IRS overpayment interest rate for Q2 2026, covering the period from April 1, 2026 through June 30, 2026, is established at 6% per annum, compounded daily.
This rate is pegged to the federal short-term rate established by the Federal Reserve, rounded to the nearest full percentage point, plus three percentage points. At the prevailing federal short-term rate under the current restrictive monetary policy environment, this produces the 6% rate confirmed in IRB 2026-8.
The Internal Revenue Bulletin 2026-8 is the authoritative primary source confirming this rate. Any taxpayer receiving interest on a delayed refund during Q2 2026 will see this 6% annual rate applied to their calculation, compounded daily from April 15, 2026 through the date the IRS issued the refund.
How the Daily Compounding Calculation Works
The IRS does not calculate a simple annual interest figure and divide by 12. It applies daily compounding using interest factor tables established in Revenue Procedure 95-17. This means your interest accrues on an escalating principal balance each day the refund is delayed.
The daily interest factor at 6% annual compounding is 0.000164 per day. On a $3,000 refund delayed from April 15 to July 1, representing 77 days past the April 15 starting date and 32 days past the May 30 threshold, the calculation runs as follows.
Daily interest on $3,000 is $3,000 multiplied by 0.000164, producing $0.492 per day. Across 32 days past the 45-day threshold, that generates approximately $15.74 in interest. The IRS pays this automatically; you do not need to request it or file a separate claim.
This payment mechanism connects to the same Bureau of the Fiscal Service payment infrastructure that handles all IRS refund disbursements, routing through the Federal Reserve’s ACH network to your designated bank account.
For refunds significantly delayed due to audit holds, identity verification reviews, or processing backlogs, the interest amounts can be meaningful. A $15,000 refund held for 90 days past the 45-day threshold accumulates approximately $220 in interest at the current 6% compounded daily rate.
The 45-Day Rule in Detail
The 45-day clock operates differently depending on when you filed your return. If you filed your 2025 federal return by the April 15, 2026 deadline, the 45-day clock started on April 15, 2026. The interest-free window closed on May 30, 2026. Any refund issued May 30 or earlier carries no interest obligation. Any refund issued May 31 or later carries interest backdated to April 15.
If you filed after April 15, the clock starts on the date your return was actually filed, not the deadline date. A taxpayer who filed on May 1 and received a refund on June 30 would have the 45-day clock running from May 1, making June 15 the threshold date. That taxpayer is owed 15 days of interest from June 15 through June 30.
If you filed an extension and submitted your return in October, the 45-day clock starts on the date your extended return was received by the IRS. The IRS refund after extension article covers how extension filers interact with the overpayment interest rules and the specific timeline adjustments that apply.
This Interest Is Taxable Income
Here is what most taxpayers miss: the interest the IRS pays on your delayed refund is taxable income. The IRS will issue you a Form 1099-INT in January 2027 reflecting the interest paid during calendar year 2026. You must report that interest income on your 2026 federal tax return filed in 2027.
This is a straightforward tax obligation, but it catches many people off guard because the interest arrives either as a separate check or as an additional deposit alongside the refund, and taxpayers frequently treat it as part of their refund rather than as separate taxable income. The IRS system codes this payment separately in your transcript, and the Form 1099-INT that follows in January confirms the exact amount.
Understanding how late refund interest interacts with your overall tax liability connects to the broader context of how the U.S. money movement system tracks and disburses different types of federal payments, each with distinct coding and reporting requirements.
How to Check Whether You Are Owed Interest
The most reliable method for determining whether your refund triggered the interest obligation is to compare your actual refund deposit date against the May 30 threshold. Your actual deposit date is visible in your bank transaction history and in the IRS transcript as the date associated with Transaction Code 846, which is the IRS code for a completed refund release.
If your IRS Code 846 date is May 31, 2026 or later and you filed by April 15, you are entitled to interest. If your 846 date is May 30 or earlier, you are within the 45-day window and owe no interest.
For returns that were flagged for additional review under Transaction Code 570, experienced a refund freeze under Code 810, or received a CP53E notice indicating an undelivered payment, the delay timeline almost certainly crossed the 45-day threshold.
The IRS Code 570 additional action pending and IRS Code 810 refund freeze articles cover how these review codes affect the delay calculation and the interest entitlement that accumulates during extended holds.
The interest on your late refund will arrive either as part of your refund payment or as a separate ACH deposit within days of the primary refund. The IRS does not always send it simultaneously, and some taxpayers receive the interest component two to four weeks after the primary refund clears.
If your refund arrived after May 30 and you have not received a separate interest payment or seen additional funds arrive, check your IRS Online Account transcript for any pending disbursement entries.
