The IRS charges interest on unpaid taxes, whether you're on a payment plan or not

The interest rate the IRS charges is set by law and changes quarterly. For the first quarter of 2024, the rate is 8 percent per year. This rate applies to all unpaid federal taxes, including the original tax bill, penalties, and any interest that has already accrued. The IRS does not reduce or waive the interest rate because you've set up a payment plan — you pay interest on whatever balance remains unpaid, for as long as it remains unpaid.

Interest compounds daily. That means each day the IRS adds a small amount to what you owe, and the next day's interest is calculated on that larger amount. Over a multi-year payment plan, this daily compounding can add thousands of dollars to your original debt. The longer your plan runs, the more interest you pay.

You also owe a failure-to-pay penalty of 0.5 percent per month on any unpaid balance, separate from interest. This penalty also compounds and continues to accrue until the debt is fully paid. Together, interest and penalties can nearly double what you originally owed if the payment plan stretches over several years.

Key Takeaways

  • The IRS interest rate is set quarterly by law and was 8 percent annually in early 2024, but you should check the current rate on IRS.gov because it changes.
  • Interest accrues daily on your unpaid balance, including penalties, so a longer payment plan means significantly more interest paid overall.
  • A failure-to-pay penalty of 0.5 percent per month also applies to unpaid taxes on a payment plan, separate from interest charges.
  • The only way to stop interest and penalties from growing is to pay the full balance; payment plans do not pause or reduce these charges.

How the IRS calculates interest on your specific payment plan

The IRS uses a straightforward formula: it multiplies your unpaid balance by the current interest rate, then divides by 365 to get the daily charge. That daily amount is added to your balance every single day. When you make a payment, the IRS applies it first to penalties, then to interest, then to the original tax debt. This means early in your payment plan, most of your payment goes toward interest and penalties rather than reducing the principal.

For example, if you owe $10,000 in taxes and set up a 24-month payment plan at roughly $417 per month, the first payment might reduce your balance by only $200 or $300 because the rest covers interest and penalties that have accrued since the tax was due. By month 12, your payments start reducing the principal faster because less interest has accumulated on the smaller remaining balance.

The IRS publishes the interest rate quarterly in Revenue Ruling notices. The rate is the federal short-term rate plus 3 percentage points. You can find the current rate on IRS.gov or ask the IRS directly when you set up your plan. The rate does not change mid-plan — you lock in whatever rate is current when you enter the agreement — but the rate you pay may differ from what someone else pays if they set up their plan in a different quarter.

Payment plans that cost less in interest

A short-term payment plan (120 days or fewer) has no setup fee and stops interest from growing as quickly because you're paying the debt off faster. If you can pay within four months, this route costs far less in total interest than a multi-year plan. The IRS will not charge you a user fee for this arrangement.

An installment agreement (longer than 120 days) does charge a setup fee, typically $31 to $225 depending on how you enter the agreement and your income level. Low-income taxpayers may may have access to for a reduced fee. The longer the plan, the more total interest you pay, so if you can shorten the payment period by paying larger amounts early, you reduce the interest significantly.

Paying in full when ready stops all interest and penalties from accruing further. If you can borrow money at a lower rate than the IRS charges, that may be worth exploring — a personal loan at 6 percent, for instance, would cost less than the IRS's 8 percent plus the 0.5 percent monthly penalty. However, most people cannot access credit at rates lower than the IRS rate, so a payment plan is often the only realistic option.

What happens if you miss a payment on your plan

Missing even one payment can terminate your installment agreement. Once the agreement ends, the full remaining balance becomes due when ready, and the IRS may begin collection actions including wage garnishment or bank levies. Interest and penalties continue to accrue on the full balance during this time.

If you know you cannot make a scheduled payment, contact the IRS before the due date. You may be able to modify the plan — extending it further (which increases total interest) or temporarily suspending payments if you're experiencing hardship. The IRS is more likely to work with you if you reach out proactively rather than straightforward missing the payment.

How to see your current interest and penalty charges

The IRS sends you a notice showing the breakdown of your debt: original tax, penalties, and interest. You can also create an account on IRS.gov and view your account transcript, which shows daily interest accruals and penalty charges. If you have a payment plan in place, your monthly statement will show how much of each payment goes to interest, penalties, and principal.

Request a tax account transcript from the IRS if you want a detailed history. This document shows every charge, payment, and interest calculation applied to your account. It's useful if you're trying to understand why your balance is higher than you expected or if you're considering paying off the plan early.

Paying off your plan early to reduce interest

You can pay off your installment agreement at any time without penalty. Doing so stops interest and penalties from accruing on the remaining balance. If you receive a tax refund, inheritance, bonus, or other lump sum, explore it to your IRS debt when ready saves you money in interest.

The math is straightforward: every dollar you pay reduces the balance on which interest accrues. If you have six months left on a two-year plan and you can pay the remaining balance in full, you save roughly six months of interest charges. The IRS will not penalize you for early payment, and there's no benefit to stretching out a payment plan longer than necessary.

Frequently Asked Questions

Can the IRS lower the interest rate on my payment plan?

No. The interest rate is set by federal law and applies to all taxpayers equally. The IRS cannot reduce it, and you cannot negotiate it. The only way to reduce the total interest you pay is to shorten the payment plan by paying larger amounts or paying in full.

Does the interest rate change while I'm on a payment plan?

No. The rate is locked in when you enter the agreement. If the IRS rate changes in a future quarter, your rate stays the same for the duration of your plan. However, if you modify or extend your plan, the new rate in effect at that time applies going forward.

What's the difference between interest and the failure-to-pay penalty?

Interest is the cost of borrowing money from the IRS — it's calculated as a percentage of your unpaid balance. The failure-to-pay penalty is a separate charge of 0.5 percent per month on unpaid taxes. Both accrue daily and both are added to what you owe. You cannot avoid either one by being on a payment plan.

If I pay my installment agreement early, do I owe less interest?

Yes. Interest stops accruing once you pay the balance in full. If you pay off your plan six months early, you avoid six months of interest charges on the remaining balance. There's no penalty for early payment, so paying faster always saves you money.

How do I find out what the current IRS interest rate is?

The IRS publishes the interest rate quarterly on IRS.gov. You can also call the IRS at 1-800-829-1040 and ask for the current rate. The rate changes on January 1, April 1, July 1, and October 1 each year based on the federal short-term rate plus 3 percentage points.