What is a 40 year mortgage payment?
Type the home price, your down payment and the rate. The 40 year mortgage calculator gives the monthly principal and interest over 480 payments, the total interest, and how much lower the payment and how much higher the interest are than on a 30-year loan.
- Monthly payment
- $1,873.46
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.
- Loan amount
- $320,000.00
- Total interest
- $579,261.66
- Total of payments
- $899,261.66
- Payment over 30 years
- $2,022.62
- Monthly difference vs 30 years
- $149.16
- Extra interest vs 30 years
- $171,119.30
Monthly payment: $1,873.46. 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.
How much of what you pay is interest?
The results are estimates for information only. They are not financial, tax, or legal advice. Check the numbers with your lender or a qualified professional before you decide. Terms of use
How to calculate
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.
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.
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.
- 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
Each example is checked against the calculator on every build.
- Home price $400,000.00, Down payment $80,000.00, Interest rate 6.5%, Loan term (years) 40 gives Monthly payment $1,873.46, Total interest $579,261.66, Payment over 30 years $2,022.62, Monthly difference vs 30 years $149.16, Extra interest vs 30 years $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)
- Home price $300,000.00, Down payment $50,000.00, Interest rate 6%, Loan term (years) 40 gives Monthly payment $1,375.53, Total interest $410,256.37, Payment over 30 years $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)
- Home price $250,000.00, Down payment $50,000.00, Interest rate 0%, Loan term (years) 40 gives Monthly payment $416.67, Total interest $0.00.
How it works
With price V, down payment D, yearly rate j (percent) and Y years (40 by default):
- Loan amount L = V − D. A down payment of the whole price or more gives no answer.
- Monthly rate r = j ÷ 1,200, and number of payments n = 12 × Y (480 for 40 years).
- Monthly payment M = L × r ÷ (1 − (1 + r)^−n), the same as OpenStax’s P × r(1 + r)^n ÷ ((1 + r)^n − 1). At 0%, M = L ÷ n.
- Total interest = M × n − L (0 at 0%). Total of payments = L + total interest.
- Payment over 30 years = the same M with n = 360. Monthly difference vs 30 years = 30-year payment − M. Extra interest vs 30 years = total interest − 30-year total interest.
Price $1,000 to $1 billion; rate 0% to 30%; term 30 to 50 years (the page compares a longer term with 30 years). Payments are not rounded between steps; money shows to the cent, rounded half up.
Assumptions
- A fixed rate for the whole term, monthly payments, no extra payments, and no fees.
- The payment is principal and interest only.
Worked examples by hand
$400,000 home, $80,000 down, 6.5%, 40 years (the default). L = $320,000; r = 0.065 ÷ 12; n = 480. M = $1,873.46; total interest $579,261.66. Over 30 years: M = $2,022.62 with $408,142.36 of interest, so the 40-year payment is $149.16 lower a month and costs $171,119.30 more interest.
$300,000 home, $50,000 down, 6%, 40 years. L = $250,000; M = $1,375.53; total interest $410,256.37. Over 30 years M = $1,498.88.
$250,000 home, $50,000 down, 0%, 40 years. M = 200,000 ÷ 480 = $416.67; no interest.
Other questions people ask
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.