Adjustable-Rate Mortgage (ARM) Calculator
Calculate your initial ARM payment, remaining balance at adjustment, and new payment after the rate resets.
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How to use this tool
- Enter the loan amount and the initial fixed rate.
- Pick the ARM type — 3/1, 5/1, 7/1, or 10/1 — which sets how many years the rate is locked.
- Enter your estimate of the rate after adjustment to see the new payment and how much it could change.
An adjustable-rate mortgage (ARM) starts with a lower fixed rate for a set number of years — 3, 5, 7, or 10 — then adjusts to a new rate for the remainder of the term. This calculator shows your initial payment, the balance remaining when the rate resets, and an estimated new payment so you can compare an ARM against a fixed-rate mortgage before committing.
⚠ This tool provides general estimates for education only and is not financial, tax or legal advice. Figures may not reflect your situation — verify with a qualified professional.
Frequently asked questions
- What does '7/1 ARM' mean?
- The first number is how many years the initial rate is fixed (7 years); the second is how often it adjusts after that (every 1 year). A 10/1 ARM locks the rate for 10 years, then adjusts annually.
- How is the initial payment calculated if it's not a fixed-rate loan the whole time?
- Lenders amortize ARM payments as if the initial rate applied for the full loan term, then recalculate the payment on the remaining balance once the rate resets — that's exactly what this calculator does.
- Is the payment after adjustment guaranteed?
- No — this is an estimate based on the rate you enter. Real ARMs adjust based on an index plus margin, usually with rate caps limiting how much it can move at each adjustment.