Mortgage & real estate

ARM Mortgage Calculator

Enter the loan, the fixed period and both rates to see the initial payment and what it becomes after the first reset.

  • Free
  • No sign-up
  • Updated for 2026

Loan & rates

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yr
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Enter the loan, fixed period and rates to see the ARM payments.

Worked example

With these example inputs:

  • Loan amount$400,000
  • Initial rate5%
  • Fixed-rate period5 yr
  • Rate after reset7%
  • Full loan term30 yr

Initial monthly payment: $2,147

  • Payment after reset$2,596
  • Payment change$449
  • Balance at reset$367,315

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What this ARM mortgage calculator does

This calculator shows your initial monthly payment on an ARM. You enter the loan, both rates, and the periods. The tool then prices the start and the reset. So you see the first payment and the later one. It also shows the change at reset. The result uses the currency you choose.

What an ARM is

An ARM is an adjustable-rate mortgage. It starts with a fixed rate for some years. Then the rate resets to a new level. So the payment can rise after the fixed period. It often starts cheaper than a fixed loan. But the later rate is less certain.

How it is calculated

The tool first amortizes the loan amount at the initial rate. It finds the payment over the full term. At reset, it reprices the balance at the new rate. So the payment jumps if the rate climbs. The result is your initial monthly payment. The calculator runs the numbers for you.

What the result tells you

The result shows your initial monthly payment. Four hundred thousand at five percent starts near two thousand one hundred. A higher initial rate raises it. A bigger loan raises it too. So it shows the early bill. It is just a close estimate.

The loan amount

Your loan amount is the sum you borrow. It is the price minus your down payment. A bigger loan lifts both payments. So this number sets the base. Use the amount after your deposit. It drives the entire result here. Enter your loan amount.

The initial rate

Your initial rate is the fixed starting rate. It holds for the first few years. A lower start cuts the early payment. So this number sets the first bill. Use the quoted teaser rate. It is often below a fixed loan. Enter your initial rate.

The fixed-rate period

Your fixed-rate period is how long the start holds. It is the years before the first reset. A longer fixed period delays the change. So this number sets when the rate moves. Common terms are five or seven years. Pick the one in your offer. Enter your fixed-rate period.

The rate after reset

Your rate after reset is the new rate later. It applies once the fixed period ends. A higher reset rate lifts the new payment. So this number drives the jump. Use a cautious estimate here. Rates can climb a lot. Enter your rate after reset.

The full loan term

Your full loan term is the total length. It is the years to pay it all off. A longer term lowers each payment. So this number spreads the cost. Thirty years is the common choice. The reset payment uses the years left. Enter your full loan term.

The payment after reset

The tool also shows the payment after reset. It is the bill once the rate changes. Here it climbs by about four hundred. So the jump can strain a budget. The balance at reset drives it too. It is the risk of an ARM.

A final tip

Use this to weigh an ARM with open eyes. Remember the reset payment can rise sharply. Test a higher reset rate to be safe. Make sure you could afford the jump. The start is cheap, the later cost less sure. Do not bank on refinancing. A careful choice needs the worst case.

Frequently asked questions

How does an adjustable-rate mortgage work?

You pay a fixed rate for an initial period, then the rate adjusts. A 5/1 ARM is fixed for five years, then resets annually. This tool shows the payment before and after the first reset.

What happens at the reset?

The remaining balance is re-amortized over the remaining term at the new rate. If the rate rises, the payment jumps. A 5% rate moving to 7% can raise a payment by hundreds per month.