How the ARM Calculator Works

It estimates payments on an adjustable-rate mortgage across the fixed introductory period and the adjustment periods that follow, including worst-case rate caps.

How It Works, Step by Step

The calculator amortizes at the low intro rate during the fixed period, then projects payments at the maximum the rate can reach under the caps, so you see both the best case and the worst case after the loan adjusts.

ARMs can appeal to Florida buyers who expect to sell or refinance before the fixed period ends — common in a state with seasonal residents and frequent relocations. Just stress-test the worst case: if you might still own the home when it adjusts, make sure the capped payment is one you could absorb.

Want the underlying math? See the arm formula page, or open the calculator to try it with your own figures.