# Mortgage Amortization Calculator

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

> The mortgage amortization calculator shows how each payment splits between interest and principal over time – the balance, principal paid and interest paid after any number of years – and the totals over the loan.

## Inputs

- Loan amount
- Interest rate (%)
- Loan term (years, months)
- After how many years?

## Results

- Monthly payment
- Remaining balance
- Principal paid so far
- Interest paid so far
- First payment – interest part
- First payment – principal part
- Total interest over the loan
- Equity from paydown

## Formula

```
Payment M = P × i ÷ (1 − (1 + i)^−n)
Balance after k payments = P(1 + i)^k − M[(1 + i)^k − 1] ÷ i
Principal paid = P − balance; interest paid = k × M − principal paid
```

## Explanation

Early in a mortgage most of each payment is interest; by the end it's almost all principal. On a 30-year loan at 6.5%, it takes about 20 years before more than half of each payment goes to principal.

### How to use the Mortgage Amortization Calculator

- **Loan amount**
- **Interest rate**
- **Loan term**
- **After how many years?**

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

### How it works

Enter the loan details and the number of years to look at.

### 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 amountAmount in your currencyInterest rateIn %Loan termUnits: years, monthsAfter how many years?A number

### What each result means

- **Monthly payment** = pmt([Interest rate]÷1200, [Loan term], [Loan amount])
- **Remaining balance** = max(bal([Loan amount], [Interest rate]÷1200, [Loan term], min([After how many years?]×12, [Loan term])), 0)
- **Principal paid so far** = [Loan amount] - [Remaining balance]
- **Interest paid so far** = [Monthly payment]×min([After how many years?]×12, [Loan term]) - [Principal paid so far]
- **First payment – interest part** = [Loan amount]×[Interest rate]÷1200
- **First payment – principal part** = [Monthly payment] - [First payment – interest part]
- **Total interest over the loan** = [Monthly payment]×[Loan term] - [Loan amount]
- **Equity from paydown** = [Principal paid so far]÷[Loan amount]×100

### Example values

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

Loan amountMonthly payment160,0001,011.31240,0001,516.96320,0002,022.62400,0002,528.27480,0003,033.93640,0004,045.24

## Worked example

Inputs — Loan amount: $320,000; Interest rate: 6.5 %; Loan term: 30 years; After how many years?: 5.

Results — **Monthly payment = $2,022.62**; Remaining balance = $299,555.13; Principal paid so far = $20,444.87; Interest paid so far = $100,912.19; First payment – interest part = $1,733.33; First payment – principal part = $289.28; Total interest over the loan = $408,142.36; Equity from paydown = 6.39 %.

## FAQ

**What is amortization?**
Paying off a loan with regular payments that cover interest and principal.

**Why is most of my payment interest at first?**
Interest is charged on the balance, which is largest at the start.

**When do I pay more principal than interest?**
On a 30-year loan at 6–7%, after roughly 18–21 years.

**What formula does the Mortgage Amortization Calculator use?**
Payment M = P × i ÷ (1 − (1 + i)^−n).


## Sources

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