ARM Calculator

Calculate adjustable rate mortgage payments and see how your payments may change when the interest rate adjusts. Compare ARM vs fixed-rate mortgage options.

Loan Information

ARM Structure

Max rate change per adjustment

Max rate increase over loan life

Rate Projections

Current SOFR or LIBOR rate

Lender's margin above index

Expected future index rate

Current Payment

Initial Rate: 0.00%
Monthly Payment: $0.00
Loan Amount: $0

First Adjustment

Year: Year 0
New Rate: 0.00%
New Payment: $0.00

Worst Case Scenario

Max Rate: 0.00%
Max Payment: $0.00
Payment Increase: $0.00

ARM Payment Schedule

Enter details and click "Calculate" to view ARM payment schedule

Understanding Adjustable Rate Mortgages

An Adjustable Rate Mortgage (ARM) has an interest rate that can change periodically, typically after an initial fixed-rate period. ARMs offer lower initial rates but carry the risk of payment increases.

How ARMs Work

  • Initial Period: Fixed rate for 3, 5, 7, or 10 years
  • Adjustments: Rate changes annually after initial period
  • Index + Margin: New rate = current index rate + lender's margin
  • Caps: Limits on how much and how often rates can change
  • Reset Period: Usually adjusts annually (1-year ARM)

Common ARM Types

5/1 ARM

  • 5 years fixed rate
  • Adjusts annually after year 5
  • Most popular ARM type
  • Good for short-term ownership

7/1 ARM

  • 7 years fixed rate
  • Adjusts annually after year 7
  • Longer fixed period
  • Higher initial rate than 5/1

ARM Caps and Limits

  • Initial Adjustment Cap: Limits first rate change (usually 2-5%)
  • Periodic Adjustment Cap: Limits subsequent changes (usually 2%)
  • Lifetime Cap: Maximum rate increase over loan life (usually 5-10%)
  • Floor Rate: Minimum rate the ARM can adjust to
  • Payment Cap: Some ARMs limit payment increases (not rate)

ARM vs Fixed-Rate Mortgage

ARM Advantages

  • Lower initial interest rates
  • Lower initial monthly payments
  • Good for short-term ownership
  • Can refinance before adjustments

ARM Risks

  • Payments can increase significantly
  • Rate uncertainty
  • Potential payment shock
  • Harder to budget long-term

Tip: ARMs are best for borrowers who plan to sell or refinance within the initial fixed-rate period. Consider your long-term plans and risk tolerance before choosing an ARM.

Related Mortgage Calculators