An amortization schedule is a table with one row per loan payment. Each row shows the payment amount, how much of it goes to interest, how much reduces the principal, and the remaining balance. Read it top to bottom and you can see exactly when your balance will drop below a target, how much interest you will pay in any year and how much equity your payments build. The key pattern: interest starts high and shrinks, while principal starts small and grows, because interest is always charged on the balance that is left.
The columns, explained
Lenders and calculators format schedules a little differently, but nearly all include these columns:
| Column | What it means | How it is calculated |
|---|---|---|
| Payment number or date | Which payment the row describes | 1 to n, or the due date |
| Beginning balance | Principal owed before this payment | Previous row’s ending balance |
| Payment | Scheduled principal-and-interest amount | Fixed for a fixed-rate loan |
| Interest | Cost of borrowing for the period | Beginning balance × periodic rate |
| Principal | Amount that reduces the debt | Payment − interest |
| Ending balance | Principal owed after this payment | Beginning balance − principal |
| Cumulative interest | Total interest paid so far | Running sum of the interest column |
| Cumulative principal | Total principal repaid so far | Running sum of the principal column |
Some schedules add an extra-payment column and an escrow column; others group rows by year.
The formulas behind every row
Each row uses three simple steps:
The payment itself comes from the standard annuity formula: Payment = P × i ÷ (1 − (1 + i)−n), where i is the monthly rate. If you want to see that formula worked through, read how to calculate mortgage interest.
Example: $250,000 at 6% for 30 years
The monthly rate is 0.06 ÷ 12 = 0.005, and the payment is $1,498.88. Here are selected rows, with interest rounded to the cent each month as lenders do:
| Payment | Interest | Principal | Ending balance | Cumulative interest |
|---|---|---|---|---|
| 1 | $1,250.00 | $248.88 | $249,751.12 | $1,250.00 |
| 2 | $1,248.76 | $250.12 | $249,501.00 | $2,498.76 |
| 3 | $1,247.51 | $251.37 | $249,249.63 | $3,746.27 |
| 12 | $1,235.96 | $262.92 | $246,929.94 | $14,916.50 |
| 60 | $1,164.85 | $334.03 | $232,635.66 | $72,568.46 |
| 120 | $1,048.32 | $450.56 | $209,213.77 | $139,079.37 |
| 180 | $891.14 | $607.74 | $177,621.13 | $197,419.53 |
| 223 | $745.78 | $753.10 | $148,401.94 | $232,652.18 |
| 240 | $679.14 | $819.74 | $135,007.39 | $244,738.59 |
| 300 | $393.17 | $1,105.71 | $77,527.87 | $277,191.87 |
| 360 | $7.44 | $1,488.01 | $0.00 | $289,593.37 |
Check row 1 yourself: $250,000 × 0.005 = $1,250.00 interest; $1,498.88 − $1,250.00 = $248.88 principal; $250,000 − $248.88 = $249,751.12. Row 2 starts from that new balance. The amortization calculator prints all 360 rows.
Five things to look for
1. How slowly the balance falls at first
After a full year, the balance has dropped only $3,070.06, while you paid $14,916.50 in interest. After five years, about 81% of everything you paid ($72,568 of $89,933) went to interest. This is normal for long loans, and it is why refinancing or selling in the first few years leaves most of the original balance still owed.
2. The crossover point
Find the first row where principal exceeds interest. Here it is payment 223, about 18 and a half years in. Before that point, interest is the larger share of every payment; after it, principal is. A higher rate or longer term pushes the crossover later.
3. Equity milestones
To find when you will owe less than a target, scan the ending-balance column. On this loan the balance falls below $200,000 around year 12 and below half the original amount only in year 21. If you put 10% down and want to reach 20% equity to drop private mortgage insurance, the schedule tells you which row gets you there (assuming the home’s value holds). Under the Homeowners Protection Act, PMI on most conventional loans ends automatically when the balance is scheduled to reach 78% of the original value.
4. Interest in a given year
Add the interest column for the 12 rows in that year, or subtract cumulative interest at the start of the year from the end. For tax purposes, your lender reports mortgage interest paid on Form 1098 each January.
5. Total cost
The last row’s cumulative interest, $289,593.37, is the lifetime interest cost, more than the amount borrowed. Total payments are the loan plus that interest, about $539,593.
Why the final payment is different
Because each month’s interest is rounded to the cent, tiny differences accumulate. In this example, the last regular-looking payment would overshoot, so payment 360 is $1,495.45 (the remaining $1,488.01 principal plus $7.44 interest). Your servicer handles this automatically, but it explains why a schedule you build in a spreadsheet may end a few dollars off.
Variations you may see
- Biweekly schedules have 26 rows per year. Paying half the monthly amount every two weeks adds up to 13 full payments a year, which shortens a 30-year loan by several years.
- Equal-principal schedules keep the principal portion fixed and let the total payment shrink over time; the equal principal amortization calculator shows one.
- Adjustable-rate loans recalculate the payment at each reset, so the rows after an adjustment use the new rate and a new payment.
- Interest-only periods show zero principal until amortization begins, followed by a jump in the payment.
- Auto and personal loans work the same way, but with shorter terms the crossover happens much sooner. Model them with the loan calculator.
Using the schedule to make decisions
The schedule makes trade-offs concrete. Extra principal paid in row 1 removes interest from every one of the remaining 359 rows, which is why early prepayment is so powerful; see how much extra mortgage payments save. Comparing two schedules side by side, such as a 15-year and a 30-year loan, shows the cost of a lower payment in hard numbers. The mortgage payoff calculator rebuilds the schedule with extra payments so you can see the new payoff date.
This guide is educational and not financial advice. Your servicer's records, including rounding and payment application rules, determine your actual balance; request an official payoff statement before paying off a loan.
Frequently asked questions
What is an amortization schedule?
It is a table showing each scheduled payment on an installment loan, the part that pays interest, the part that reduces principal and the balance left afterward. It applies to mortgages, auto loans, student loans and most personal loans.
Why does the last payment differ from the others?
Each month's interest is rounded to the cent, and those tiny rounding differences accumulate. The final payment is adjusted so the balance lands exactly on zero, which usually makes it a few dollars higher or lower than the regular payment.
How do I find how much equity I will have after five years?
Look up the remaining balance on row 60 and subtract it from your home's value. On a $250,000 loan at 6% for 30 years, the balance after 60 payments is $232,635.66, so payments alone have built $17,364.34 of equity, before any price change or down payment.
Does an amortization schedule include taxes and insurance?
No. A standard schedule covers principal and interest only. Escrow amounts for property tax, homeowners insurance and mortgage insurance are added to your monthly bill separately and can change from year to year.
What happens to the schedule if I pay extra?
Extra principal lowers the balance immediately, so every later row shows less interest and more principal, and the loan ends early. Your required payment usually stays the same; the schedule simply gets shorter.