# Mortgage with Extra Payments Calculator

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

> The mortgage with extra payments calculator shows how extra monthly payments and a one-time lump sum shorten your mortgage and cut total interest, with the new payoff date.

## Inputs

- Loan balance
- Interest rate (%)
- Remaining term (years, months)
- Extra per month
- One-time extra payment
- Month of the one-time payment
- Next payment date

## Results

- Monthly payment
- Months to pay off with extra payments
- New payoff date
- Time saved
- Total interest without extra payments
- Total interest with extra payments
- Interest saved

## Formula

```
Balance after a lump sum at month k = balance(k) − lump sum
Months to pay off with extra = nper(i, M + extra, balance)
Interest saved = original total interest − new total interest
```

## Explanation

Extra payments reduce the principal immediately, so the interest charged every month after is smaller. The earlier you pay extra, the more you save.

### How to use the Mortgage with Extra Payments Calculator

- **Loan balance**
- **Interest rate**
- **Remaining term**
- **Extra per month**
- **One-time extra payment**
- **Month of the one-time payment**
- **Next payment date**

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

### How it works

Enter the loan balance, interest rate, remaining term, extra monthly payment and any one-time payment with the month it is made.

### Tips

- Get a written loan estimate and compare the APR, not just the interest rate.
- Include property tax, insurance, HOA fees and maintenance in your monthly budget.
- A larger down payment lowers the payment and can remove mortgage insurance.
- Rates change daily – use a current quote for the most accurate result.

### Common mistakes to avoid

- Looking only at the monthly payment instead of the total cost of the loan.
- Forgetting closing costs and fees.
- Assuming home prices always rise.

### Inputs explained

FieldWhat to enterLoan balanceAmount in your currencyInterest rateIn %Remaining termUnits: years, monthsExtra per monthAmount in your currencyOne-time extra paymentAmount in your currencyMonth of the one-time paymentA numberNext payment dateA date

### What each result means

- **Monthly payment** = pmt([Interest rate]÷1200, [Remaining term], [Loan balance])
- **New payoff date** = addmonths([Next payment date], [Months to pay off with extra payments] - 1)
- **Time saved** = ([Remaining term] - [Months to pay off with extra payments])÷12
- **Total interest without extra payments** = [Monthly payment]×[Remaining term] - [Loan balance]
- **Total interest with extra payments** = ([Monthly payment] + [Extra per month])×[Months to pay off with extra payments] + [One-time extra payment] - [Loan balance]
- **Interest saved** = [Total interest without extra payments] - [Total interest with extra payments]

### Example values

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

Loan balanceInterest saved125,00059,043.29187,50069,401.72250,00076,163.53312,50080,936.46375,00084,489.57500,00089,431

## Worked example

Inputs — Loan balance: $250,000; Interest rate: 6.5 %; Remaining term: 25 years; Extra per month: $200; One-time extra payment: $5,000; Month of the one-time payment: 12; Next payment date: 2026-11-24.

Results — Monthly payment = $1,688.02; Months to pay off with extra payments = 225; New payoff date = Mon, July 24, 2045; Time saved = 6.2 years; Total interest without extra payments = $256,405.37; Total interest with extra payments = $180,241.84; **Interest saved = $76,163.53**.

## FAQ

**Do extra payments go to principal?**
Yes, if you tell your lender to apply them to principal.

**Is it better to pay extra monthly or a lump sum?**
Earlier is better; regular extras and lump sums both work.

**Are there prepayment penalties?**
Rare on U.S. mortgages since 2014 but check your loan terms.

**What formula does the Mortgage with Extra Payments Calculator use?**
Balance after a lump sum at month k = balance(k) − lump sum.


## Sources

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