Free ARM Calculator

Compare an adjustable-rate mortgage to a fixed-rate by estimating payments during the initial fixed period and after the first rate adjustment.

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ARM Initial Payment

$2,334.29

Estimated Payment After Adjustment$2,802.64
Fixed Rate Payment (comparison)$2,594.39
Monthly Savings During Fixed Period$260.10
Total Savings During Fixed Period$15,606
Balance at Rate Adjustment$371,049

ARM Initial Payment vs Initial Fixed Period

Adjustable-Rate Mortgage (ARM)

An ARM starts with a lower fixed rate for an initial period, then adjusts periodically based on a market index plus a margin.

Common ARM Structures

  • 5/1 ARM: Fixed for 5 years, adjusts annually
  • 7/1 ARM: Fixed for 7 years, adjusts annually
  • 10/1 ARM: Fixed for 10 years, adjusts annually
  • Rate Caps

    ARMs have caps limiting rate changes:

  • Initial cap: Maximum first adjustment (typically 2%)
  • Periodic cap: Maximum annual adjustment (typically 2%)
  • Lifetime cap: Maximum over loan life (typically 5-6%)
  • When an ARM Makes Sense

  • You plan to sell or refinance before the fixed period ends
  • You want to maximize cash flow in the early years
  • You believe rates will stay stable or decrease
  • Example Calculation

    A $400,000 loan. 5/1 ARM at 5.75% initial, expected adjustment to 7.75%. Comparable 30-year fixed at 6.75%.

    1. 01ARM initial payment (5.75%, 30-year amortization): $2,334.29
    2. 02Fixed rate payment (6.75%): $2,594.26
    3. 03Monthly savings during initial period: $2,594.26 - $2,334.29 = $259.97
    4. 04Total savings over 5 years: $259.97 x 60 = $15,598
    5. 05Balance at year 5: approximately $371,342
    6. 06Adjusted payment at 7.75% for remaining 25 years: $2,803.14

    Frequently Asked Questions

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