What amortization means
Amortization is paying a debt off in regular installments so the amount owed falls to zero by the last payment. The Consumer Financial Protection Bureau defines it the same way, and adds that some loans do not fully amortize, so a balance can remain after the final regular payment.1
Every payment is split in two: interest, the lender's charge for the money you still owe, and principal, the part that actually reduces the debt. Interest is worked out on the balance left at that moment, not on the original amount, so the interest share falls and the principal share rises as the loan ages. In month one of the example loan, $1,625.00 of the $1,896.20 payment (85.7%) is interest.2
Amortization is different from an interest-only loan, where the payment covers interest and the balance does not fall, and from a balloon loan, where a large lump sum is left at the end. This calculator handles the balloon case (see the checkbox above); an interest-only loan needs no schedule, because the payment is simply the balance times the monthly rate.
What do extra payments save?
Because interest is charged on the balance still owed, extra principal paid early avoids interest on every remaining month. The table shows the example loan ($1,896.20 a month for 30 years) with different extras. Each row is calculated by this calculator; use the checkbox above to try your own.
| Scenario | Total interest | Paid off in | Interest saved |
|---|---|---|---|
| No extra payment | $382,633.47 | 30 years | - |
| Extra $100 every month | $321,638.68 | 26 years | $60,994.79 |
| Extra $200 every month | $279,184.67 | 23 years, 1 month | $103,448.79 |
| Extra $500 every month | $202,874.38 | 17 years, 6 months | $179,759.08 |
| One extra full payment a year ($1,896.20) | $292,080.70 | 24 years, 1 month | $90,552.76 |
| One-time $10,000 at payment 60 (year 5) | $345,277.83 | 28 years | $37,355.63 |
Three things to check before sending extra money: that your loan allows prepayment without a penalty, that the lender applies the extra to principal rather than holding it toward the next payment, and that you are not skipping a higher-interest debt for a lower one.
Are biweekly payments worth it?
A biweekly plan sends half the monthly payment every two weeks, which is 26 half payments, or 13 full payments, in a year instead of 12.1 The whole benefit is that one extra payment. On the example loan, one extra full payment a year saves $90,552.76 and pays the loan off 5 years, 11 months sooner (the "One extra full payment a year" row above). The CFPB has sued a company that charged setup and processing fees for this service,3 and the same result is available for free: add a yearly extra payment, or divide your payment by twelve and add that to each monthly payment. The "Use one extra full payment" button in the form fills the yearly extra with your payment.
Monthly payment by loan amount and rate
If you only need the payment, this table answers it without typing. It shows the principal-and-interest payment on a 30-year fixed loan. For example, $400,000 at 7% is $2,661.21 a month. Property tax, insurance and mortgage insurance come on top of this; the mortgage amortization calculator adds them.
| Loan amount | 5% | 5.5% | 6% | 6.5% | 7% | 7.5% | 8% |
|---|---|---|---|---|---|---|---|
| $100,000 | $536.82 | $567.79 | $599.55 | $632.07 | $665.30 | $699.21 | $733.76 |
| $150,000 | $805.23 | $851.68 | $899.33 | $948.10 | $997.95 | $1,048.82 | $1,100.65 |
| $200,000 | $1,073.64 | $1,135.58 | $1,199.10 | $1,264.14 | $1,330.60 | $1,398.43 | $1,467.53 |
| $250,000 | $1,342.05 | $1,419.47 | $1,498.88 | $1,580.17 | $1,663.26 | $1,748.04 | $1,834.41 |
| $300,000 | $1,610.46 | $1,703.37 | $1,798.65 | $1,896.20 | $1,995.91 | $2,097.64 | $2,201.29 |
| $400,000 | $2,147.29 | $2,271.16 | $2,398.20 | $2,528.27 | $2,661.21 | $2,796.86 | $2,935.06 |
| $500,000 | $2,684.11 | $2,838.95 | $2,997.75 | $3,160.34 | $3,326.51 | $3,496.07 | $3,668.82 |
The payment formula, derived step by step
The monthly payment formula falls out of one requirement: after the last scheduled payment the balance must be exactly zero.
Step 1: define the variables.
Step 2: the balance after one payment. Each month the balance first grows by one month's interest, then shrinks by the payment:
Step 3: unroll it. Applying that rule n times and summing the resulting geometric series gives the balance after n payments:
Step 4: set the balance to zero and solve for M. A fully amortizing loan means Bₙ = 0, so:
Step 5: the special case r = 0. With no interest the formula divides by zero, because (1 + r)ⁿ − 1 becomes 0. The answer is simpler and needs no formula:
A calculator that skips this branch crashes or returns the wrong number on a 0% promotional loan. This one checks for it explicitly.
Worked example with exact numbers
A $300,000 loan at 6.5% a year for 30 years (360 monthly payments), the defaults loaded in the calculator above.
The first payment, month by month:
| Item | Amount |
|---|---|
| Starting balance | $300,000.00 |
| Interest (balance × 0.00541667) | $1,625.00 |
| Principal (payment − interest) | $271.20 |
| Balance after payment 1 | $299,728.80 |
| Balance after payment 2 | $299,456.12 |
Over the full 30 years: total interest is $382,633.47 and the total paid is $682,633.47.
Enter the same numbers above and every figure matches, because the page and this text are produced by the same code.
Want the spreadsheet version?
The Download Excel button above gives you this schedule as a workbook with a formula in every row. The amortization schedule page shows how to build the same table yourself in Excel or Google Sheets with the PMT, IPMT and PPMT functions.
Frequently asked questions
What is an amortization schedule (or amortization table)?
An amortization schedule, also called an amortization table, lists every payment on a loan and splits it into interest and principal, with the balance left after each one. The yearly summary above adds the payments up by calendar year; the full schedule under it shows every month.
How is my monthly payment calculated?
M = P × r × (1 + r)ⁿ ÷ ((1 + r)ⁿ − 1), where P is the loan amount, r is the monthly rate (the annual rate divided by 12) and n is the number of payments. The derivation is above. A 0% loan is handled separately as P ÷ n, because the formula divides by zero when r = 0.
Why do early payments go mostly to interest?
Interest is charged on the balance still owed, so in month one you pay interest on the whole loan. On the example loan, $1,625.00 of the first $1,896.20 payment (85.7%) is interest and only $271.20 reduces the balance. As the balance falls the interest shrinks, and more of the same payment goes to principal.
How do monthly, yearly and one-time extra payments work?
Extra money is applied straight to principal, so the balance falls faster and less interest is charged on it next month. A monthly extra repeats every payment from the payment number you choose, a yearly extra is made in the month you pick each year, and a one-time extra is made once at the payment number you choose. You can combine all three. Confirm with your lender that extra payments go to principal and that your loan has no prepayment penalty.
How much does an extra $100 a month save on a 30-year loan?
On $300,000 at 6.5% for 30 years, an extra $100 a month saves $60,994.79 in interest and pays the loan off 4 years sooner. An extra $200 saves $103,448.79 (6 years, 11 months sooner) and an extra $500 saves $179,759.08. Your result depends on your rate and on how early you start, so change the numbers above.
Do biweekly payments really pay off a loan faster?
Yes, but only because of the extra money. Half your payment every two weeks is 26 half payments a year, which is 13 full payments instead of 12. On the example loan, one extra full payment a year saves $90,552.76 and finishes 5 years, 11 months sooner. Some companies charge fees to set this up. You can get about the same effect for free with a yearly extra payment, and the "Use one extra full payment" button above fills it in.
What is negative amortization?
Negative amortization is when a payment is smaller than the interest due, so the unpaid interest is added to the balance and the loan grows instead of shrinking. This calculator refuses a payment below the first month's interest for that reason. Some loans, such as balloon loans, do not fully amortize either, so money can still be owed after the last regular payment.
Can I make a schedule for a loan I am already paying?
Yes. Enter your current balance as the loan amount, your current rate, the number of payments you have left as the term, and the date of your next payment. The schedule shows what remains. Your servicer's statement can differ by a few cents because of rounding and day counts.
How do I pay off a $300,000 loan in 5 years?
Set the term to 5 years. At 6.5% the payment is $5,869.84, about 3.1 times the 30-year payment of $1,896.20, and the total interest falls to $52,190.67. If that payment is too high, steady extra payments get you part of the way: see the table of extras above.
What is a balloon loan and how do I model it?
A balloon loan has regular payments worked out over a long term but the whole remaining balance due at an earlier date. Tick "Balloon loan" and enter the years until it is due. With the example loan and a 7-year balloon the payment stays $1,896.20, and $271,248.73 is still owed at payment 84 and has to be paid or refinanced then.
Does a 0% interest loan need an amortization schedule?
Yes, the schedule is just simpler. With no interest every payment is the same size and goes entirely to principal, so the payment is the loan amount divided by the number of payments. The standard formula cannot be used directly because it divides by zero at 0%, so it is handled as its own case.
What is the difference between amortization and simple interest?
Simple interest charges a flat rate on the original amount for the whole term, so the interest is the same every period. An amortized loan charges interest only on the current balance, so the interest falls every month as you pay. Most mortgages and installment loans are amortized. The simple interest calculator shows the other method.
Does the start date change my payment amount?
No. The start date only changes the calendar dates shown next to each payment and the payoff date. The payment, the total interest and the total paid depend only on the loan amount, rate and term.
Why is my lender's payment a few cents different?
Small differences come from rounding or day-count conventions. Some lenders round every payment to the cent and adjust only the last one, and some use a 365/360 day count that slightly changes the effective monthly rate. This calculator works each month from the remaining balance and brings the schedule to exactly zero, which matches most lenders within a few cents.
Should I enter the interest rate or the APR?
Enter the loan's stated interest rate (the note rate), not the APR. The APR spreads lender fees and closing costs over the term, so it is higher than the interest rate and is not the number the monthly payment is calculated from.
Can I download the schedule?
Yes. Download CSV exports every payment (number, date, payment, principal, interest and balance, plus extra and balloon columns when you use them) as a file that opens in Excel, Google Sheets or Numbers. Download Excel gives a workbook with live formulas: change the amount, the rate, the start date or the Extra and Balloon columns and every row recalculates, and a shorter term works too. The sheet has exactly as many rows as the schedule you downloaded, so for a longer term or a smaller payment it needs more rows; a check in row 10 says whether the balance reaches zero and, if it does not, to copy the last row down. Print / Save as PDF gives a paper or PDF copy.
Is what I type sent anywhere?
No. The calculation runs in your browser and the numbers you enter are not sent to a server. We count page visits and button clicks with our own analytics on our own server, and those events carry no amounts or inputs.
Sources
- Consumer Financial Protection Bureau, Mortgage key terms: definitions of amortization and of a bi-weekly payment (half the monthly payment every two weeks, 26 payments a year).
- Consumer Financial Protection Bureau, How does paying down a mortgage work? (last reviewed May 28, 2024): most of an early payment is interest, and more goes to principal over time.
- Consumer Financial Protection Bureau, CFPB Files Suit Against Nationwide Biweekly for Luring Consumers with False Promises of Mortgage Savings (May 11, 2015): describes a paid biweekly program as effectively making one additional monthly payment a year, and the fees it charged.
The payment formula, the schedule and every figure in the tables are calculated by this page's own code. The code is checked against an independent implementation in the site's test suite.