Amortization Calculator
Build a full amortization schedule for any loan — monthly and yearly tables, principal vs interest split, and a lookup of any single payment's breakdown.
Amortization Calculator: with the default inputs, total interest is $318,861.
Annual note rate.
See the principal, interest and balance for one specific payment.
Interest over the whole schedule.
- Monthly payment
- $1,580.17
- Total of all payments
- $568,861
- Final payment date
- August 10, 2056
- Number of payments
- 360
- Principal in inspected payment
- $239.84
- Interest in inspected payment
- $1,340.33
- Balance after inspected payment
- $247,205.69
- Interest paid through that payment
- $16,168
- Interest saved by extra payments
- $0
Assumptions
- Fixed rate, level monthly payments made at the end of each month, interest charged monthly at the annual rate ÷ 12.
- Extra payments are applied entirely to principal.
| Payment | Date | Amount | Principal | Interest | Balance |
|---|---|---|---|---|---|
| 1 | 2026-09-10 | $1,580.17 | $226.00 | $1,354.17 | $249,774.00 |
| 2 | 2026-10-10 | $1,580.17 | $227.23 | $1,352.94 | $249,546.77 |
| 3 | 2026-11-10 | $1,580.17 | $228.46 | $1,351.71 | $249,318.31 |
| 4 | 2026-12-10 | $1,580.17 | $229.70 | $1,350.47 | $249,088.61 |
| 5 | 2027-01-10 | $1,580.17 | $230.94 | $1,349.23 | $248,857.67 |
| 6 | 2027-02-10 | $1,580.17 | $232.19 | $1,347.98 | $248,625.48 |
| 7 | 2027-03-10 | $1,580.17 | $233.45 | $1,346.72 | $248,392.04 |
| 8 | 2027-04-10 | $1,580.17 | $234.71 | $1,345.46 | $248,157.32 |
| 9 | 2027-05-10 | $1,580.17 | $235.98 | $1,344.19 | $247,921.34 |
| 10 | 2027-06-10 | $1,580.17 | $237.26 | $1,342.91 | $247,684.07 |
| 11 | 2027-07-10 | $1,580.17 | $238.55 | $1,341.62 | $247,445.53 |
| 12 | 2027-08-10 | $1,580.17 | $239.84 | $1,340.33 | $247,205.69 |
| Year | Principal | Interest | Total paid | Balance |
|---|---|---|---|---|
| 1 | $2,794 | $16,168 | $18,962 | $247,206 |
| 2 | $2,981 | $15,981 | $18,962 | $244,224 |
| 3 | $3,181 | $15,781 | $18,962 | $241,043 |
| 4 | $3,394 | $15,568 | $18,962 | $237,649 |
| 5 | $3,621 | $15,341 | $18,962 | $234,027 |
| 6 | $3,864 | $15,098 | $18,962 | $230,163 |
| 7 | $4,123 | $14,839 | $18,962 | $226,041 |
| 8 | $4,399 | $14,563 | $18,962 | $221,642 |
| 9 | $4,694 | $14,269 | $18,962 | $216,948 |
| 10 | $5,008 | $13,954 | $18,962 | $211,940 |
How this is worked out
The formula
Payment M = P × r(1 + r)^n ÷ ((1 + r)^n − 1) Interest in month k I_k = B_(k−1) × r Principal in month k P_k = M − I_k Balance after month k B_k = B_(k−1) − P_k P = loan amount, r = monthly rate (annual ÷ 12), n = number of payments
Open How it’s calculated above to see this worked through with your own numbers.
What you enter
- Loan amount
- A number.in dollars · 0 or more · defaults to 250000
- Interest rate
- Annual note rate.a percentage · from 0 to 100 · defaults to 6.5
- Term
- A number.from 1 to 50 · whole numbers only · defaults to 30
- Payment number to inspect
- See the principal, interest and balance for one specific payment.from 1 to 600 · whole numbers only · defaults to 12
- First payment date(under More options)
- A calendar date.defaults to today
- Extra monthly payment(under More options)
- Applied straight to principal every month.in dollars · 0 or more · defaults to 0
What you get back
- Total interestmain answer
- Interest over the whole schedule.
- Monthly payment
- Total of all payments
- Final payment date
- Number of payments
- Principal in inspected payment
- Interest in inspected payment
- Balance after inspected payment
- Interest paid through that payment
- Interest saved by extra payments
What this assumes
- Fixed rate, level monthly payments made at the end of each month, interest charged monthly at the annual rate ÷ 12.
- Extra payments are applied entirely to principal.
About this calculator
An amortization schedule is the loan's full itinerary: for every payment it lists how much went to interest, how much to principal, and what you still owe afterwards. The payment itself never changes on a fixed-rate loan, but its composition does — the first payment on a 30-year, 6.5% mortgage is 86% interest; the last is 99.5% principal. Seeing the whole table is the fastest way to understand why extra payments early matter so much and why refinancing late in a loan saves less than it seems.
How to use it
Enter the amount, rate and term. The monthly schedule is the main event: every payment with its date, split and running balance. The yearly table underneath summarizes each year. Type a payment number in Payment number to inspect to pull out one row — handy for "how much interest have I paid after three years?" or "what will my balance be at payment 60?". Open More options to set the first payment date or add an extra monthly amount.
Reading the schedule
- Interest in any month is simply the previous balance times the monthly rate. That's why it declines a little every month.
- Principal is the rest of the payment. It grows by the same amount interest shrinks.
- Balance falls slowly at first and faster later. Roughly half the principal on a 30-year loan is paid in the final third of the term.
- Interest paid through that payment is the cumulative figure you'd compare with a Form 1098 or use when deciding whether a refinance is still worth it.
What the total tells you
Total interest is the headline number. For a 30-year loan at 6.5%, it's about 1.28× the amount borrowed; at 15 years it drops to roughly 0.57×. Shortening the term or prepaying principal are the only two levers on a fixed-rate loan — the rate is set at signing.
Limitations
The schedule assumes a fixed rate and level payments. Adjustable-rate loans re-amortize at each reset, interest-only periods delay principal entirely, and lenders that compute daily interest will show cents of difference depending on when a payment posts.
Frequently asked questions
▸What is an amortization schedule?
A table listing every payment on a loan with its interest portion, principal portion and remaining balance. It shows how a level payment gradually shifts from mostly interest to mostly principal.
▸How do I find how much interest I've paid so far?
Enter the number of payments you've made in "Payment number to inspect". The result "Interest paid through that payment" sums the interest column up to that row.
▸Why does so little go to principal at the start?
Interest is charged on the outstanding balance, which is largest at the start. On $250,000 at 6.5%, the first month's interest is $1,354 of a $1,580 payment. As the balance falls, interest falls with it.
▸Does the schedule change if I pay extra?
Yes. Extra principal lowers next month's balance, so every subsequent row has less interest and more principal. The loan ends early and the total interest drops — add an extra amount under More options to see the new table.
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