Interest accrues on every IRS payment plan, starting from the day your tax debt was due
The IRS charges interest on any unpaid tax balance, regardless of whether you set up a payment plan. The interest rate is set by federal law and changes quarterly. As of early 2024, the rate is 8 percent per year, compounded daily. This means interest grows on top of your original tax bill and on the interest already added.
A payment plan does not stop interest from running. It only lets you pay what you owe in smaller monthly chunks instead of all at once. Every dollar you owe continues to accrue interest until the full balance—original tax plus all interest—is paid off.
The IRS also charges penalties on top of interest. The most common is the failure-to-pay penalty, which is 0.5 percent of your unpaid tax per month (or part of a month). If you did not file your return on time, you may also owe a failure-to-file penalty. These penalties stack with interest and continue to grow until your account is settled.
Key Takeaways
- Interest on IRS debt runs at a quarterly rate set by federal law, currently 8 percent per year, and compounds daily whether or not you have a payment plan.
- The failure-to-pay penalty adds 0.5 percent of your unpaid tax per month until the balance is cleared, separate from interest charges.
- Setting up a payment plan stops the failure-to-pay penalty from growing once you are in compliance, but interest continues on the remaining balance.
- The longer your payment plan runs, the more interest and penalties you will pay overall, because interest compounds on a larger balance for a longer time.
- Paying off your balance faster reduces the total amount of interest and penalties you owe, even if your monthly payment is smaller.
How interest and penalties stack on a payment plan
Imagine you owe $5,000 in back taxes. The IRS assesses interest at 8 percent per year, compounded daily. On day one of your debt, you owe $5,000 plus a small amount of daily interest. By the end of the first month, interest has added roughly $33 to your balance. You now owe $5,033.
If you set up a payment plan and pay $200 per month, your first payment reduces the balance to $4,833. But interest continues to accrue on that $4,833. By the time your second payment is due, interest has added another $32. You pay $200 again, leaving $4,665, and the cycle repeats.
The failure-to-pay penalty also runs during your payment plan. It adds 0.5 percent of your original unpaid tax each month. On a $5,000 debt, that is $25 per month. However, once you enter into a formal payment plan agreement with the IRS, the penalty rate drops to 0.25 percent per month instead of 0.5 percent. This is one concrete benefit of having a plan in place.
Over a 24-month payment plan, the combination of interest and the reduced penalty can easily add $1,000 or more to your original debt, depending on the size of what you owe and the exact timing of payments.
The difference between short-term and long-term payment plans
The IRS offers two main types of payment plans: short-term (120 days or fewer) and long-term (installment agreements that can run several years). Both accrue interest and penalties, but the total amount you pay in interest differs significantly based on how long the plan runs.
A short-term plan is essentially a brief delay before you pay in full. If you can pay your debt within 120 days, the interest and penalty charges will be much smaller than if you stretch the plan over three or five years. The IRS charges a setup fee for short-term plans (currently $31 to $225 depending on how you set it up), but the interest savings often outweigh that cost.
A long-term installment agreement lets you spread payments over months or years, which makes each monthly payment manageable but increases the total interest paid. A $5,000 debt paid over 60 months will cost significantly more in interest than the same debt paid over 24 months, even though your monthly payment is lower.
When the IRS stops charging penalties on your plan
The failure-to-pay penalty stops growing once you are current on your payment plan. This means if you make your payments on time, the penalty will not increase beyond what has already accrued. However, interest continues to run on your remaining balance for as long as you owe money.
If you miss a payment on your plan, the penalty can resume at the higher 0.5 percent rate until you catch up. This is why staying current on your payment plan is important—missing payments not only delays your payoff but also restarts penalty growth.
Interest, by contrast, never stops. It runs from the original due date of your tax return until the day your account balance reaches zero. There is no way to avoid it or have it waived through a payment plan.
How to calculate what you will actually pay
The total amount you pay on a payment plan is your original tax debt plus all interest and penalties that accrue during the plan period. The IRS does not provide a straightforward calculator for this on their website, but you can estimate it roughly.
Start with your unpaid tax balance. Add the current interest rate (8 percent per year, compounded daily) for the length of your plan. Add the failure-to-pay penalty: 0.25 percent per month once you are in a formal agreement. For example, a $3,000 debt on a 36-month plan would accrue roughly $720 in interest and $270 in penalties, bringing your total to about $3,990.
These are estimates, not exact figures, because interest compounds daily and the rate can change quarterly. The IRS will provide an exact payoff amount when you set up your plan, and that figure is what you will owe if you make all payments on time.
Why paying faster reduces your total cost
The most direct way to reduce interest and penalties is to pay off your debt as quickly as possible. Even small increases to your monthly payment can save hundreds of dollars over the life of the plan.
If you can pay $300 per month instead of $200, you will clear a $5,000 debt in 17 months instead of 25 months. That eight-month difference means eight fewer months of interest accruing and eight fewer months of penalty charges. On a debt that size, that could save $200 to $400 in total charges.
This is why the IRS offers short-term plans with lower setup fees—they want to encourage faster payoff. If you have any way to pay your balance more quickly, even if it means a tighter monthly budget for a few months, the interest savings make it worthwhile.
Frequently Asked Questions
Can the IRS lower or remove the interest on my payment plan?
No. Interest is set by federal law and applies to all unpaid tax debt. The IRS cannot waive it or reduce the rate. However, you can request an Offer in Compromise (a settlement for less than you owe) or Currently Not Collectible status (a temporary pause on collection), both of which stop penalty growth but not interest.
Does the interest rate change while I am on a payment plan?
Yes. The IRS adjusts the interest rate quarterly based on federal law. If rates go up, your interest charges will increase. If rates go down, your charges will decrease. The rate change applies to your remaining balance, not retroactively to what you have already paid.
What happens to interest if I pay off my plan early?
Interest stops accruing the day your balance reaches zero. If you pay off your plan early, you will owe less total interest because it has run for fewer months. The IRS will not refund interest already paid, but you will not owe any additional interest after your final payment.
Is the interest on an IRS payment plan tax deductible?
Interest on federal income tax debt is generally not deductible. However, if you owe tax on a business or rental property, some interest may be deductible as a business expense. Consult a tax professional about your specific situation, as the rules depend on how the debt arose.
What if I cannot afford my payment plan because of interest charges?
Contact the IRS and ask about modifying your plan to a lower monthly payment, which will extend the plan length but reduce the when ready burden. You can also request Currently Not Collectible status, which temporarily pauses collection efforts, though interest and penalties continue to accrue.