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Your loan, month by month
On the default — $400,000 at 7.00% for 30 years: $2,661.21/mo, $558,036 in total interest. Enter your own loan below and scroll the full schedule.
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Amortization Schedule Calculator
Enter any fixed-rate loan and see the whole story: the monthly payment, how every payment splits into principal and interest, the total interest you will pay, and the month-by-month schedule — printable, all the way to the final payment.
How amortization works: the payment stays, the split moves
A fixed-rate loan charges interest on whatever you still owe, every month: interest = balance × (rate ÷ 12). Your payment is sized so that after the final payment the balance hits exactly zero. Early on the balance is huge, so most of each payment is interest — on the $400,000 default, month 1 sends $2,333.33 to interest and only $327.88 to principal. As the balance shrinks, the interest slice shrinks with it, and the principal slice grows — by the final year, 97% of each payment retires principal. Same payment every month, completely different job.
Output · formula · meaning
| Output | Formula | What it means |
|---|---|---|
| Monthly payment (P&I) | P × i ÷ (1 − (1 + i)−n), i = rate/12 | $400,000 at 7%, 360 payments → $2,661.21. |
| Each month’s interest | remaining balance × rate ÷ 12 | Month 1: $2,333.33 — 88% of the payment. |
| Each month’s principal | payment − interest | Month 1: $327.88 — the part that actually shrinks the debt. |
| Total interest | payment × n − loan amount | $558,036 — 58% of every dollar repaid is interest. |
| Payoff date | start month + n months | Counted forward from today — the schedule labels every month. |
Why the early years feel like treading water
After 10 years of $2,661.21 payments — $319,345 paid — the balance is still about $342,000. Only $58,000 of principal is gone; the rest was interest. That is not a trick: it is the arithmetic of charging 7% on a large balance every month. It is also the entire case for extra principal early: $200/month extra from day one cuts the default loan to about 24 years and saves roughly $103,000 in interest (run it on the extra payment calculator). The same $200 started in year 15 saves a fraction of that — the schedule shows why.
15 years vs 30 years on the same $400,000
30 years at 7%: $2,661.21/mo × 360 = $958,036 total — $558,036 interest. 15 years at 7%: $3,595.31/mo × 180 = $647,156 total — $247,156 interest. The 15-year payment is only 35% bigger, but it erases $310,823 of interest — more than half. That is the price of stretching the schedule: time is what interest feeds on.
Reading your schedule like a lender
Three columns do all the work. Balance is what you would owe if you sold or refinanced that month — lenders quote payoffs from exactly this column. Interest vs principal tells you whether extra payments are worth it right now (early: yes, enormously; late: barely). And the month labels turn the abstract “payment 214” into “August 2044,” which is when humans actually make decisions. Print the page and the whole table comes with it.
Who uses this
- Homebuyers: seeing the true lifetime cost behind the monthly payment — $958,036, not $400,000.
- Refinance shoppers: comparing the remaining-interest column of the old loan against the new loan’s total.
- Extra-payment planners: finding the exact month where an extra principal payment does the most damage to interest.
- Sellers & landlords: the balance column is the payoff number for any sale or refinance date.
Accuracy & limitations
Standard fixed-rate amortization with exact double-precision math; the final payment is adjusted so the balance lands on zero. Displays round to cents; totals may differ from a lender’s by a few dollars due to day-count conventions. Payment is principal & interest only — taxes, insurance, and PMI are not in this schedule (see the mortgage calculator for the full PITI picture). Assumes a fixed rate for the whole term; adjustable-rate loans re-price and need lender software.
Want to attack the interest column? The extra payment calculator shows what $100 or $200 more a month does to this exact schedule, the recast vs refinance calculator compares the two big alternatives, and the loan payment calculator sizes any loan’s payment in seconds.
Cite this calculatorBright Side Kit. “Amortization Schedule Calculator.” brightoolbox.com, 2026.
Bright Side Kit. "Amortization Schedule Calculator." https://brightoolbox.com/amortization-schedule-calculator/ Accessed October 22, 2026.Frequently asked questions
What is an amortization schedule?
A month-by-month ledger of a fixed-rate loan: every payment, how much of it was interest, how much was principal, and the remaining balance. The calculator above builds the full table for any loan.
Why is my early payment almost all interest?
Because interest is charged on the remaining balance — and early on, that balance is at its biggest. On $400,000 at 7%, month 1 is $2,333 interest vs $328 principal. As the balance falls, the split flips.
How is the monthly payment calculated?
Payment = P × i ÷ (1 − (1+i)−n), where i is the monthly rate and n the number of payments. It is the single payment that zeroes the balance exactly at month n.
Does paying extra change the schedule?
Yes — every extra dollar of principal skips its future interest. $200/month extra on the default loan cuts ~6 years and ~$103,000 of interest. Run your numbers on the extra payment calculator.
Is a 15-year mortgage really that much cheaper?
Dramatically. $400,000 at 7%: the 30-year costs $558,036 in interest; the 15-year costs $247,213 — for a payment only 35% higher. Time is what interest feeds on.
Does the schedule include property tax and insurance?
No — this is principal and interest only. Taxes, insurance, and PMI ride on top unchanged. The mortgage calculator shows the full monthly picture.
What do I owe if I sell in year 7?
Read the balance column at that month — that is your payoff number (plus any lender fees). The schedule turns “payment 84” into a real date.
What about biweekly payments?
Paying half the monthly amount every two weeks makes 26 half-payments = 13 full payments a year — one extra payment annually, shaving years off. The biweekly calculator runs it exactly.