# What is a 40 year mortgage payment?

Works out the monthly payment and total interest on a 40-year fixed-rate mortgage (480 payments), and how they compare with the same loan over 30 years.

- Page: https://www.acalculator.org/finance/40-year-mortgage-calculator
- JSON spec: https://www.acalculator.org/finance/40-year-mortgage-calculator.json
- Version: 12ea0421efec

## Default answer

Example with the default inputs (Home price $400,000.00, Down payment $80,000.00, Interest rate 6.5%, Loan term (years) 40): A 40-year loan of $320,000.00 at 6.5% costs $1,873.46 a month, with $579,261.66 of interest in total.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| price | Home price | The price of the home. |
| down | Down payment | The cash you pay toward the price. The loan is the price minus this. |
| rate | Interest rate | The fixed yearly rate your lender quotes. The monthly rate is this ÷ 12. |
| years | Loan term (years) | The length of the mortgage: 40 years on this page, or any term from 30 to 50, to compare with 30 years. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| payment | Monthly payment | Principal and interest each month. |
| loan | Loan amount | The price minus the down payment. |
| interest | Total interest | Every payment added up, minus the loan. |
| total | Total of payments | The loan plus the total interest. |
| payment30 | Payment over 30 years | The same loan and rate over 30 years, for comparison. |
| less | Monthly difference vs 30 years | The 30-year payment minus this payment. |
| more | Extra interest vs 30 years | This term’s total interest minus the 30-year total. |

## Method

Loan L = price − down payment. Monthly rate r = yearly rate ÷ 1,200 and n = years × 12 payments. Payment M = L × r ÷ (1 − (1 + r)^−n), or L ÷ n at 0%. Total interest = M × n − L. The 30-year figures use n = 360.

## Assumptions

- A fixed rate for the whole term, monthly payments, and no extra payments. The payment is principal and interest only: property tax, insurance, HOA dues and mortgage insurance are extra.
- A loan term over 30 years is not a qualified mortgage under the CFPB’s ability-to-repay rule (12 CFR 1026.43(e)(2)(ii)), so fewer lenders offer it.

## Worked examples

1. price = $400,000.00, down = $80,000.00, rate = 6.5%, years = 40 gives payment = $1,873.46, interest = $579,261.66, payment30 = $2,022.62, less = $149.16, more = $171,119.30. Source: Total paid = pmt × 12 × t. https://openstax.org/books/contemporary-mathematics/pages/6-12-renting-and-homeownership (retrieved 2026-10-18).
2. price = $300,000.00, down = $50,000.00, rate = 6%, years = 40 gives payment = $1,375.53, interest = $410,256.37, payment30 = $1,498.88. Source: Total paid = pmt × 12 × t. https://openstax.org/books/contemporary-mathematics/pages/6-12-renting-and-homeownership (retrieved 2026-10-18).
3. price = $250,000.00, down = $50,000.00, rate = 0%, years = 40 gives payment = $416.67, interest = $0.00.

## FAQ

### What is the payment on a 40-year mortgage?

On $320,000 at 6.5%, $1,873.46 a month for 480 months, against $2,022.62 over 30 years: $149.16 a month less.

### How much more interest does a 40-year mortgage cost?

On $320,000 at 6.5%, $579,261.66 of interest over 40 years against $408,142.36 over 30 years: $171,119.30 more, for a payment $149.16 lower.

### Is a 40-year mortgage a qualified mortgage?

No. Under the CFPB’s ability-to-repay rule, a qualified mortgage has a loan term of no more than 30 years (12 CFR 1026.43(e)(2)(ii)). Lenders can still offer longer terms, but fewer do.

### How is a 40-year mortgage payment calculated?

With loan L, monthly rate r = yearly rate ÷ 12 and n = 480 payments, the payment is L × r ÷ (1 − (1 + r)^−n). At 0%, it is L ÷ 480.

### Does the payment include taxes and insurance?

No. It is principal and interest only. Property tax, homeowners insurance, HOA dues and mortgage insurance are added on top; the full mortgage calculator includes them.

### Who offers 40-year mortgages?

Some lenders offer them as non-qualified mortgages, and a loan modification can stretch a term to 40 years. Ask your lender which terms it offers and at what rate; a longer term often carries a higher rate.

## Sources

- OpenStax, Contemporary Mathematics, section 6.12 Renting and Homeownership: the monthly mortgage payment pmt = P × (r/12) × (1 + r/12)^(12t) ÷ ((1 + r/12)^(12t) − 1) for principal P, yearly rate r and t years; total paid = pmt × 12 × t. Retrieved 2026-10-18. https://openstax.org/books/contemporary-mathematics/pages/6-12-renting-and-homeownership
- Consumer Financial Protection Bureau, Regulation Z, 12 CFR 1026.43(e)(2)(ii): a qualified mortgage is one “for which the loan term does not exceed 30 years”. Retrieved 2026-10-18. https://www.consumerfinance.gov/rules-policy/regulations/1026/43/