ARM Calculator (Adjustable Rate Mortgage)
Adjustable-rate mortgages (ARMs) often start with a lower interest rate than a fixed loan. Our ARM calculator estimates your monthly payment during the fixed period and models how payments can change after the rate adjusts using index + margin, caps, and a full amortization schedule.
Use this page to compare 3/1, 5/1, 7/1, and 10/1 hybrid ARMs and explore current ARM rates from available lenders. When you’re ready, the rate table below can help you compare real offers.
ARM Payment Calculator
We estimate your payment during the fixed period, then model future adjustments using index + margin with caps (initial, periodic, lifetime).
This ARM model uses index + margin assumptions and applies caps to simulate payment changes. Actual lender terms can vary.
ARM Summary
Current ARM Mortgage Rates
Compare available ARM offers below. You can switch between common ARM products (3/1, 5/1, 7/1, 10/1).
Rate availability and eligibility depend on borrower profile, location, property, and lender guidelines.
Amortization & Yearly Summary
By default, we show a shorter preview so the section stays compact. Click Show all to expand the full schedule.
First 12 months (preview)
| Month | Rate | P&I | Interest | Principal | Balance |
|---|---|---|---|---|---|
| 1 | 5.75% | $1,867.43 | $1,533.33 | $334.10 | $319,665.90 |
| 2 | 5.75% | $1,867.43 | $1,531.73 | $335.70 | $319,330.20 |
| 3 | 5.75% | $1,867.43 | $1,530.12 | $337.31 | $318,992.89 |
| 4 | 5.75% | $1,867.43 | $1,528.51 | $338.93 | $318,653.96 |
| 5 | 5.75% | $1,867.43 | $1,526.88 | $340.55 | $318,313.42 |
| 6 | 5.75% | $1,867.43 | $1,525.25 | $342.18 | $317,971.23 |
| 7 | 5.75% | $1,867.43 | $1,523.61 | $343.82 | $317,627.41 |
| 8 | 5.75% | $1,867.43 | $1,521.96 | $345.47 | $317,281.94 |
| 9 | 5.75% | $1,867.43 | $1,520.31 | $347.12 | $316,934.82 |
| 10 | 5.75% | $1,867.43 | $1,518.65 | $348.79 | $316,586.03 |
| 11 | 5.75% | $1,867.43 | $1,516.97 | $350.46 | $316,235.57 |
| 12 | 5.75% | $1,867.43 | $1,515.30 | $352.14 | $315,883.44 |
Yearly summary
| Year | Avg rate | Total P&I | Interest | Principal | End balance |
|---|---|---|---|---|---|
| 1 | 5.75% | $22,409.20 | $18,292.63 | $4,116.56 | $315,883.44 |
| 2 | 5.75% | $22,409.20 | $18,049.59 | $4,359.60 | $311,523.83 |
| 3 | 5.75% | $22,409.20 | $17,792.20 | $4,616.99 | $306,906.84 |
| 4 | 5.75% | $22,409.20 | $17,519.62 | $4,889.58 | $302,017.26 |
| 5 | 5.75% | $22,409.20 | $17,230.94 | $5,178.26 | $296,839.00 |
| 6 | 6.5% | $24,051.34 | $19,150.23 | $4,901.11 | $291,937.89 |
| 7 | 6.65% | $24,377.06 | $19,259.77 | $5,117.29 | $286,820.60 |
| 8 | 6.8% | $24,695.33 | $19,338.90 | $5,356.43 | $281,464.17 |
| 9 | 6.95% | $25,005.78 | $19,384.95 | $5,620.83 | $275,843.34 |
| 10 | 7.1% | $25,308.00 | $19,394.92 | $5,913.08 | $269,930.26 |
How ARM Payments Change
Most ARMs adjust using a fully indexed rate: Index + Margin. Your rate changes at reset points, but caps limit how much it can move at each adjustment and over the life of the loan.
- Initial fixed period: your payment is stable for 5 years.
- First reset: limited by the initial cap (2 pts).
- Later resets: limited by periodic caps (2 pts).
- Lifetime cap: the rate can’t rise more than 5 pts above the start rate.
If you expect to sell or refinance before the fixed period ends, an ARM can be a useful way to lower your starting payment. But we still recommend modeling what happens if rates rise and refinancing isn’t attractive.
For deeper comparison, you can also review our Mortgage Rates & Trends guide and test scenarios using the refinance calculator.
ARM FAQs
What is an ARM (adjustable-rate mortgage)?
An ARM is a mortgage with an initial fixed interest rate for a set number of years (like 5 years), followed by rate adjustments based on an index plus a lender margin. After the fixed period, your payment can change.
How does an ARM rate get calculated after the fixed period?
Most ARMs use a fully indexed rate: index + margin. The index is a market benchmark and the margin is set by the lender. Your new rate is typically limited by caps.
What do ARM caps mean (like 2/2/5)?
Caps limit how much your rate can change. A 2/2/5 structure commonly means the first adjustment is capped at 2%, later annual changes are capped at 2%, and the total increase over the life of the loan is capped at 5% above the start rate.
Can an ARM rate go down?
Yes. If the index falls, your target rate can be lower. Most ARMs still apply periodic caps that limit how much the rate can change at each adjustment.
Is a 5/1 ARM a good idea?
A 5/1 ARM can be attractive if you plan to move or refinance before the fixed period ends, or if you want a lower initial payment. It’s important to model adjustment scenarios and ensure you can afford payment increases.
How do I compare an ARM to a fixed-rate mortgage?
Compare the initial payment savings against the risk of higher payments later. A good approach is to run both scenarios and review total interest, expected time in the home, and worst-case cap outcomes.
How to use our ARM calculator
- Enter price and down payment to estimate your loan amount.
- Choose 3/1, 5/1, 7/1, or 10/1 and enter your initial rate.
- Set index at first adjustment + margin, and add caps.
- Review initial payment, first adjusted payment, and worst-case outcomes.
Compare ARM vs Fixed Payments With Your Real Numbers
If you’re deciding between an ARM and a fixed-rate mortgage, the fastest way to get clarity is to compare monthly payments, total interest, and how your payment could change after the initial fixed period ends.
Try the Mortgage Payment Calculator