How a payment plan changes the math
An IRS payment plan, officially called an installment agreement, lets you pay what you owe over time. It doesn't freeze your balance. Interest keeps adding up until your last payment, and the late-payment penalty keeps going until the tax itself is paid off. Here's what changes once a plan is in place, and what doesn't.
- The late-payment penalty is cut in half. Normally it's 0.5% of your unpaid tax for each month or part of a month. While a plan is in effect, it's 0.25% a month. The catch: the lower rate is only for individuals whose return was filed on time, including extensions.
- Interest stays the same. It keeps running at the full IRS rate, compounded daily. The rate resets every quarter, and it's 7% for October through December 2026. The IRS interest calculator shows how that adds up, and the rate history lists every quarter.
- Payments go to tax first. The IRS generally applies each payment to tax first, then penalties, then interest. This calculator applies your payments in the same order.
Why a bigger payment saves money
The late-payment penalty and interest are both charged on what you still owe. Since each payment goes to tax first, every extra dollar shrinks the balance those charges are figured on. A bigger monthly payment means fewer months of penalty and fewer days of interest.
Try it. Enter your balance and the payment you can manage, then raise the payment and run it again. The payoff date moves up and the total cost comes down.
What the calculator assumes
To keep things simple, the calculator assumes you pay the same amount every month, on the same day of the month, until the balance is paid off, and that you paid nothing before the first plan payment. It doesn't include IRS setup fees, so add those to the total yourself. Set the filing date to when you actually filed, since the lower 0.25% rate depends on it. Real accounts can differ, and the IRS's own figure always controls.
Setting up a plan
You can apply online with the IRS Online Payment Agreement tool on irs.gov. Setup fees apply, and they're lower if you pay by direct debit from your bank account.
Once you're on a plan, keep it in good standing. Make every payment, and file and pay your future taxes on time. Missed payments or late future taxes can put the plan in default. If that happens, the lower 0.25% rate ends.
Haven't filed yet?
File on time even if you can't pay. The late-filing penalty is 5% of the unpaid tax a month, ten times the regular late-payment rate. Filing on time also keeps you eligible for the 0.25% plan rate. The late filing penalty calculator shows what filing late would add. Working under an extension? Your payment was still due in April. The extension penalty calculator covers that case.
Penalty relief still applies
Being on a plan doesn't rule out relief. If you filed the same kind of return on time for the three years before, with no penalties, first-time relief can remove the late-filing and late-payment penalties. Starting with 2025 returns the IRS applies it automatically, and under it the late-payment penalty isn't charged at all. For earlier years you ask for First Time Abate. If a penalty is removed, the interest on it goes too. Interest on the tax itself stays.
Questions people ask
Does a payment plan stop interest?
No. Interest keeps running at the full IRS rate, compounded daily, until the balance is paid. Only the late-payment penalty rate goes down.
Who gets the 0.25% late-payment rate?
Individuals with an IRS installment agreement in effect whose return was filed on time, including extensions. If the return was filed late, the penalty stays at 0.5% a month.
Are IRS setup fees included?
No. The calculator leaves out the setup fee. Fees are lower if you pay by direct debit, so check the current amounts on irs.gov when you apply.
What happens if I miss a payment?
Missing payments, or not filing and paying future taxes on time, can put the plan in default. When that happens, the reduced 0.25% rate ends.