CostA 30-year amortization lowers your monthly payment compared to 25 years, but extends the time you're paying interest, resulting in meaningfully more total interest paid over the life of the mortgage — worth weighing against the smaller monthly payment it buys you.
A worked example
$500,000 loan, 5% rate
| Monthly payment, 25-year amortization | $2,914 |
| Monthly payment, 30-year amortization | $2,671 |
| Monthly savings with 30 years | $243 |
| Total interest, 25 years | $374,200 |
| Total interest, 30 years | $461,560 |
| Extra total interest with 30 years | $87,360 |
See your own numbers side by side on the mortgage payment calculator.
Who can actually get a 30-year amortization
A 30-year amortization is generally only available on uninsured mortgages — meaning a down payment of 20% or more — since insured mortgages (under 20% down) are capped at 25 years by federal rule. If you're putting down less than 20%, 25 years is your maximum regardless of preference.
How to decide between the two
A 30-year amortization can make sense if the lower payment genuinely matters to your monthly budget or qualifying capacity — a smaller required payment is also easier to pass the stress test against. If your budget comfortably supports the 25-year payment, sticking with the shorter amortization saves real money over the life of the loan. Many mortgages also allow prepayment privileges, letting you effectively pay down a 30-year mortgage faster than scheduled without being locked into the higher required 25-year payment — see our accelerated payment guide for one way to do exactly that.