The Mortgage Ledger

United States

United States overpayment calculator

See how much interest you would save, and how many years you would cut off the mortgage, by paying a little extra each month.

Your mortgage

Paid on top of your normal payment, straight off the principal.

Overpaying $200.00/mo

$91,173

saved in interest over the life of the loan

Time cut off the mortgage
6 yrs 9 mos
Interest without overpaying
$347,515
Interest with overpaying
$256,341
US fixed mortgages rarely charge prepayment penalties today, but check your note — a few still do in the first years. There's no annual limit on extra payments on a standard conforming loan.

An estimate to help you plan — not financial advice. Assumes the extra amount is paid every month for the life of the loan and applied to principal.

Could refinancing to a lower rate save even more?

Overpaying a US mortgage — adding to your monthly payment or making lump sums — goes straight to principal, cutting both the interest you'll pay and the years left on the loan. US mortgages have no annual overpayment limit, and some lenders will recast to lower your required payment. This calculator shows the savings.

How this calculator works

Every extra dollar reduces the balance immediately, so future interest is charged on a smaller amount. The effect compounds: small monthly extras can remove years from a 30-year loan.

Unlike the UK, US mortgages generally have no prepayment penalty or annual cap — you can overpay freely. Ask your lender about recasting, which re-amortizes the lower balance into a smaller required payment.

The calculator compares your payoff date and total interest with and without the extra payments.

A worked example

A $400,000 loan at 6.5% over 30 years, adding $200/mo:

Time saved
5.6 years earlier
Interest saved
$111,892

There's no US overpayment limit — a bigger extra payment, or an early lump sum, saves even more.

Who it's for

  • You want to see the interest saved by overpaying.
  • You're deciding between a lump sum and a monthly extra.
  • You're aiming to pay the mortgage off early.

Frequently asked questions

How much do overpayments save?

A lot over time — adding $200/month to a $400,000, 6.5% loan can shorten it by several years and save tens of thousands in interest. See the example above.

Is there a limit on US mortgage overpayments?

Generally no — most US mortgages have no annual cap or prepayment penalty, so you can overpay as much as you like. Check your loan documents to be sure.

What is recasting?

After a large lump-sum payment, some lenders will re-amortize your loan over the remaining term, lowering the required monthly payment while keeping the payoff date.

Lump sum or monthly extra — which is better?

Both cut interest; what matters most is timing. Money applied earlier saves more, so an early lump sum beats the same amount spread out later.