Skip to content
AZ Tools

Loan / Mortgage Calculator

Enter the principal, the annual interest rate and the term, and get the monthly payment along with the total paid and the total interest over the life of the loan. The amortisation table then breaks each month into the part that reduces the balance and the part that is simply the cost of borrowing, with a running balance beside it — switch between a yearly summary and the full month-by-month view. That table is the point of the tool rather than a footnote: the monthly payment alone hides how heavily early payments lean towards interest, and seeing the split is what makes the effect of a shorter term or a lower rate concrete. Nothing you enter leaves your device.

Monthly payment
$1,610
Total payment
$579,767
Total interest
$279,767

Amortization

YearsPaymentPrincipalInterestBalance
1$19,326$4,426$14,899$295,574
2$19,326$4,653$14,673$290,921
3$19,326$4,891$14,435$286,031
4$19,326$5,141$14,185$280,890
5$19,326$5,404$13,922$275,486
6$19,326$5,680$13,645$269,806
7$19,326$5,971$13,355$263,835
8$19,326$6,276$13,049$257,559
9$19,326$6,597$12,728$250,961
10$19,326$6,935$12,391$244,026
11$19,326$7,290$12,036$236,736
12$19,326$7,663$11,663$229,074
13$19,326$8,055$11,271$221,019
14$19,326$8,467$10,859$212,552
15$19,326$8,900$10,425$203,652
16$19,326$9,355$9,970$194,296
17$19,326$9,834$9,491$184,462
18$19,326$10,337$8,988$174,125
19$19,326$10,866$8,459$163,259
20$19,326$11,422$7,904$151,837
21$19,326$12,006$7,319$139,830
22$19,326$12,621$6,705$127,210
23$19,326$13,266$6,059$113,943
24$19,326$13,945$5,380$99,998
25$19,326$14,659$4,667$85,340
26$19,326$15,409$3,917$69,931
27$19,326$16,197$3,129$53,734
28$19,326$17,026$2,300$36,709
29$19,326$17,897$1,429$18,812
30$19,326$18,812$513$0

How to use

  1. Enter the loan amount (principal) and annual interest rate.
  2. Set the term in years.
  3. Pick the currency for formatting.
  4. Switch between yearly and monthly schedule views.

Frequently asked questions

Which formula is used?
Standard fixed-rate amortization: M = P × r / (1 − (1 + r)^(−n)), where r is the monthly rate and n is the number of months. Each row computes interest = balance × r, principal = M − interest, then balance -= principal.
What's the difference between principal and interest portions?
Early in the loan the interest portion is largest because the balance is high. As principal is paid down, the interest shrinks and more of each payment goes to principal — the curve crossover is roughly 2/3 of the way through.
Are taxes, fees, and insurance included?
No. This is the principal-and-interest payment only. Mortgages typically add property tax, homeowner's insurance, and HOA fees that aren't modeled here.
Can I model extra payments or variable rates?
Not yet — this tool assumes a fixed rate with no prepayments. The yearly schedule shows the natural amortization curve.
Why is so little of my early payment going to the principal?
Because interest is charged on the balance you still owe, and at the start that balance is almost the whole loan. The payment is a fixed amount, so whatever is left after the interest is taken goes to the principal - which early on is a small slice. As the balance falls the interest shrinks and the principal share grows, slowly at first and then quickly towards the end.
What is the difference between the interest rate and the APR?
The interest rate is the cost of the borrowed money alone. The APR folds in the fees required to obtain the loan and expresses the whole cost as an annual rate, which is why it is usually the higher figure and the fairer one for comparing offers. This calculator works from the interest rate, so a loan with heavy fees will cost more in practice than the total shown here.
How much does a shorter term actually save?
More than most people expect, because interest accrues for fewer years on a balance that falls faster. Shortening the term raises the monthly payment and lowers the total interest, often substantially. Run the same principal and rate at two different terms and compare the total interest line - that difference is what the extra monthly amount is buying.

Related tools