# Debt Calculator

URL: https://speedycalculator.com/calculators/finance/debt/
Last updated: 2026-10-25

> The debt calculator works out how long it will take to pay off a debt at a given monthly payment – or the payment needed to clear it in a set time – with the total interest and the payoff date.

## Inputs

- Debt balance
- Interest rate (%)
- Monthly payment
- Or repay in (months)
- First payment date

## Results

- Months to pay off
- Debt-free date
- Total interest
- Monthly payment to repay in the chosen time
- Interest in the chosen time

## Formula

```
Months to repay = nper(i, payment, balance), i = rate ÷ 12
Payment for a set time = pmt(i, months, balance)
```

## Explanation

Knowing your debt-free date is motivating. If the payment barely covers the interest, the debt will take decades – raise the payment, cut the rate with a balance transfer or consolidation, or both.

### How to use the Debt Calculator

- **Debt balance**
- **Interest rate**
- **Monthly payment**
- **Or repay in**
- **First payment date**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Enter the debt balance, interest rate, your monthly payment and, optionally, the number of months you want to repay it in.

### Tips

- Compare loans by APR and total cost, not just the monthly payment.
- Extra payments go straight to principal and can save a lot of interest.
- Pay off the highest-rate debt first if you want to save the most money.
- Check for prepayment penalties before paying a loan off early.

### Common mistakes to avoid

- Stretching a loan term to lower the payment without seeing the extra interest.
- Paying only the minimum on credit cards.
- Forgetting fees that are rolled into the loan.

### Inputs explained

FieldWhat to enterDebt balanceAmount in your currencyInterest rateIn %Monthly paymentAmount in your currencyOr repay inIn monthsFirst payment dateA date

### What each result means

- **Debt-free date** = addmonths([First payment date], [Months to pay off] - 1)
- **Total interest** = [Monthly payment]×[Months to pay off] - [Debt balance]
- **Monthly payment to repay in the chosen time** = pmt([Interest rate]÷1200, [Or repay in], [Debt balance])
- **Interest in the chosen time** = [Monthly payment to repay in the chosen time]×[Or repay in] - [Debt balance]

### Example values

How the main result changes when **Debt balance** changes and everything else stays at the example values above:

Debt balanceMonths to pay off6,000179,0002712,0003815,0005118,0006724,000112

## Worked example

Inputs — Debt balance: $12,000; Interest rate: 15 %; Monthly payment: $400; Or repay in: 36 months; First payment date: 2026-11-24.

Results — **Months to pay off = 38**; Debt-free date = Mon, December 24, 2029; Total interest = $3,133.92; Monthly payment to repay in the chosen time = $415.98; Interest in the chosen time = $2,975.42.

## FAQ

**How long will it take to pay off my debt?**
Enter your balance, rate and payment – the calculator gives the exact months.

**What is the fastest way to pay off debt?**
Pay as much as possible and target the highest interest rate first.

**Should I save or pay off debt?**
Keep a small emergency fund, then pay high-interest debt first.

**What formula does the Debt Calculator use?**
Months to repay = nper(i, payment, balance), i = rate ÷ 12.


## Sources

- [Consumer Financial Protection Bureau](https://www.consumerfinance.gov/)