The IRS charges interest and penalties on top of what you owe, whether you pay in full or set up a payment plan
The interest rate the IRS charges is set by law and changes every quarter. For 2024, the rate is 8 percent per year, compounded daily. That rate applies to both unpaid taxes and penalties. The IRS also charges a failure-to-pay penalty of 0.5 percent per month on any balance you do not pay by the original due date — this stacks on top of the interest.
If you set up a payment plan, you pay both the interest and the penalty on your original tax debt. The payment plan itself does not reduce either one. You are paying interest on the full amount owed, calculated daily, for as long as the debt remains unpaid. A monthly payment plan does not stop the clock on interest accrual.
The IRS also charges a setup fee to create a payment plan. That fee depends on how you set it up and ranges from $31 to $225. This fee is separate from interest and penalties and is added to your total debt.
Key Takeaways
- The IRS interest rate is 8 percent per year for 2024, compounded daily on your unpaid balance, and this rate changes quarterly.
- You owe a failure-to-pay penalty of 0.5 percent per month on any tax not paid by the original due date, in addition to interest.
- Setting up a payment plan does not stop interest or penalties from accruing — you pay both on the full amount owed.
- The IRS charges a setup fee of $31 to $225 depending on the payment method you choose, added to your total debt.
- Interest compounds daily, so the longer your payment plan runs, the more total interest you will pay.
How the IRS calculates interest on your payment plan
Interest is calculated on your unpaid tax balance every single day. The IRS uses the daily compounding method, which means interest accrues on top of interest. If you owe $5,000 and the rate is 8 percent annually, the IRS divides that by 365 days and charges you roughly 0.022 percent per day on whatever balance remains.
The longer your payment plan runs, the more interest you pay in total. A 24-month plan will cost you significantly more in interest than a 12-month plan, even if the monthly payment is lower. The IRS does not offer a discount for paying faster or a penalty for paying slower — the interest accrues the same way regardless.
You can see the exact interest calculation on your IRS notice. The IRS breaks down the original tax, the penalties, and the interest separately so you know what portion of each payment goes toward which part of the debt.
The failure-to-pay penalty and how it works with payment plans
The failure-to-pay penalty is 0.5 percent of your unpaid tax per month, starting the day after the original tax due date. This penalty continues to accrue every month until you pay the full balance, even if you have a payment plan in place. It is separate from interest and stacks on top of it.
Unlike interest, the failure-to-pay penalty does not compound daily — it is calculated monthly. However, it still adds up quickly. On a $10,000 debt, the penalty alone is $50 per month. Over a 24-month payment plan, that is $1,200 in penalties before you even count the interest.
The IRS can reduce or remove the failure-to-pay penalty in limited cases, such as if you had reasonable cause for not paying on time or if you are a first-time penalty recipient. These reductions are rare and require you to request them in writing with documentation. Most people with payment plans pay the full penalty.
Payment plan setup fees and how they are applied
The IRS charges a setup fee when you create a payment plan. The amount depends on how you set it up:
| Setup Method | Fee |
|---|---|
| Online through IRS.gov | $31 |
| By phone with an IRS representative | $225 |
| By mail with Form 9465 | $225 |
| Installment Agreement (short-term, under $50,000) | $31 |
The setup fee is added to your total debt and is included in your payment plan. You do not pay it upfront — it rolls into what you owe. If you set up a plan online, you save $194 compared to setting it up by phone or mail.
If you already have a payment plan and want to modify it (for example, to extend the term or change the payment amount), the IRS may charge another setup fee. Check with the IRS before making changes to understand whether a new fee applies.
How interest and penalties change if you miss a payment
If you miss a payment on your plan, the IRS does not immediately cancel the agreement, but penalties and interest continue to accrue on the unpaid balance. The failure-to-pay penalty keeps adding 0.5 percent per month, and interest keeps compounding daily.
If you miss payments for a certain period (usually 120 days), the IRS can terminate your payment plan and demand the full remaining balance immediately. At that point, you are back to owing the original tax plus all accumulated interest and penalties, with no installment option available unless you request a new one.
If you know you will miss a payment, contact the IRS before the due date. You can request a short-term extension or modify your plan to lower the monthly payment. Staying in touch with the IRS is better than defaulting silently.
Comparing the total cost of different payment plan lengths
The length of your payment plan directly affects how much interest you pay. A shorter plan means less total interest; a longer plan means more. Here is how the math works on a $10,000 debt at 8 percent annual interest with a 0.5 percent monthly failure-to-pay penalty:
| Plan Length | Monthly Payment (approx.) | Total Interest (approx.) | Total Penalties (approx.) | Total Cost |
|---|---|---|---|---|
| 12 months | $833 | $400 | $600 | $11,000 |
| 24 months | $417 | $850 | $1,200 | $12,050 |
| 36 months | $278 | $1,350 | $1,800 | $13,150 |
These are approximations because interest compounds daily and the exact calculation depends on when you make each payment. The point is clear: a 36-month plan costs you $2,150 more than a 12-month plan on the same $10,000 debt. If you can afford a shorter plan, you save money.
Ways to reduce interest and penalties before setting up a payment plan
You cannot avoid interest and penalties once they are assessed, but you can reduce them before you set up a plan by paying part of the debt immediately. If you owe $10,000 and pay $3,000 right away, you only owe $7,000 on the payment plan. The interest and penalties then accrue only on that $7,000, not the full $10,000.
You can also request a penalty abatement if you have reasonable cause for not paying on time. Reasonable cause includes serious illness, a death in the family, or reliance on bad advice from a tax professional. The IRS does not grant these often, but it is worth requesting if your situation applies. Submit Form 843 (Claim for Refund and Request for Abatement) with documentation of your reason.
If you are a first-time penalty recipient with no prior tax debt, the IRS may reduce or remove the failure-to-pay penalty under the First-Time Penalty Abatement policy. You must request this in writing, and it applies only to the current year's penalties, not past years.
Frequently Asked Questions
Does the IRS charge interest on the setup fee itself?
Yes. The setup fee is added to your total debt, and interest accrues on it just like the rest of the balance. If your setup fee is $31 and you have a 24-month plan, you will pay interest on that $31 for the full 24 months.
Can I pay off my payment plan early without a penalty?
Yes. The IRS does not charge a penalty for paying off a payment plan early. You can pay the full remaining balance at any time without extra fees. However, you will still owe all interest and penalties accrued up to that point.
What happens to my interest rate if the IRS rate changes while I am on a payment plan?
Your interest rate changes automatically when the IRS rate changes. The IRS adjusts rates quarterly, and your plan rate updates with it. You do not have to do anything — the new rate applies to your remaining balance going forward.
Is there a maximum length for an IRS payment plan?
The IRS offers plans up to 72 months (six years) for most taxpayers. Longer plans mean lower monthly payments but significantly higher total interest. The IRS may require a shorter plan if your debt is small or if you have the income to pay faster.
Can I deduct the interest I pay on a payment plan?
No. Interest paid to the IRS on unpaid taxes is not deductible on your tax return. It is part of the cost of owing taxes, not a business or investment expense.