Schedule tool
Amortization Calculator & Schedule
A mortgage is paid off on a schedule called amortization: every month, one fixed payment splits into interest (the cost of borrowing) and principal (the part that actually retires the loan). The split is not even — the first years are almost entirely interest, the last years almost entirely principal — and the shape of it matters more than most rate-shopping covers.
Context rate: the Freddie Mac PMMS 30-yr average was 7.03% the week of September 24, 2026. Worked examples below use that snapshot; enter your own numbers above the fold and the schedule recomputes.
Amortization calculator
The full fixed-payment schedule: every payment splits into interest and principal, computed from the standard amortization formula — rounding happens only at display.
At these inputs
$2,669.27/mo
principal + interest · 30-year term · 360 payments
Total interest over the term
$560,939
Principal share exceeds interest at
month 243 (20 yr 3 mo)
Balance passes half the loan at
month 262 (21 yr 10 mo)
Of $960,939 paid over the term, $560,939 is interest — 58% of every dollar in the schedule.
The schedule, year by year
Principal and interest columns are cumulative. Early rows are interest-heavy by construction — interest is charged on the balance still outstanding, so the split shifts as principal retires.
| Year | Principal paid | Interest paid | Remaining balance |
|---|---|---|---|
| 1 | $4,040 | $27,991 | $395,960 |
| 2 | $8,373 | $55,690 | $391,627 |
| 3 | $13,021 | $83,073 | $386,979 |
| 4 | $18,006 | $110,119 | $381,994 |
| 5 | $23,353 | $136,803 | $376,647 |
| 6 | $29,089 | $163,099 | $370,911 |
| 7 | $35,241 | $188,978 | $364,759 |
| 8 | $41,839 | $214,411 | $358,161 |
| 9 | $48,917 | $239,365 | $351,083 |
| 10 | $56,509 | $263,804 | $343,491 |
| 11 | $64,652 | $287,693 | $335,348 |
| 12 | $73,386 | $310,990 | $326,614 |
| 13 | $82,754 | $333,653 | $317,246 |
| 14 | $92,803 | $355,635 | $307,197 |
| 15 | $103,581 | $376,889 | $296,419 |
| 16 | $115,142 | $397,359 | $284,858 |
| 17 | $127,542 | $416,990 | $272,458 |
| 18 | $140,842 | $435,721 | $259,158 |
| 19 | $155,109 | $453,486 | $244,891 |
| 20 | $170,411 | $470,215 | $229,589 |
| 21 | $186,824 | $485,833 | $213,176 |
| 22 | $204,429 | $500,259 | $195,571 |
| 23 | $223,313 | $513,407 | $176,687 |
| 24 | $243,567 | $525,183 | $156,433 |
| 25 | $265,293 | $535,490 | $134,707 |
| 26 | $288,595 | $544,218 | $111,405 |
| 27 | $313,590 | $551,255 | $86,410 |
| 28 | $340,400 | $556,476 | $59,600 |
| 29 | $369,156 | $559,752 | $30,844 |
| 30 | $400,000 | $560,939 | $0 |
Every figure here is formula output from cited defaults (rate, deductions, taxes shown in the assumptions). Planning estimate — not tax or financial advice.
Extra-payment scenarios in more depth (lump sums, biweekly equivalents): the mortgage payoff calculator. Sources: Freddie Mac PMMS (freddiemac.com/pmms). This is an estimate, not lending advice.
What amortization does, in one table
The fixed payment hides a moving split. The same $2,669.27 payment, at points along a $400,000 / 30-year life at 7.03%:
| At the end of… | Remaining balance | Principal retired | Interest paid so far |
|---|---|---|---|
| Year 1 | $395,960 | $4,040 | $27,991 |
| Year 5 | $376,647 | $23,353 | $136,803 |
| Year 10 | $343,491 | $56,509 | $263,804 |
| Year 15 | $296,419 | $103,581 | $376,889 |
| Year 30 | $0 | $400,000 | $560,939 |
Year 1 retires 1% of the loan. $4,040 of principal against a $400,000 balance — because the first year's interest bill, $27,991, eats 87.4% of that year's payments. The pace is why the break-even math on the rent-vs-buy tool is so stay-length-sensitive.
The balance halves at year 22, not year 15. Month 262 is when the outstanding balance first drops below $200,000 — past the two-thirds point of the term. “Halfway through the term” is not halfway through the loan, on dollars.
Interest is front-loaded on purpose. The formula prices every month's interest on the balance still outstanding; as principal retires, the interest share falls and the principal share rises — mechanically, not by choice. At 7.03%/30yr the crossover — the month the principal share exceeds the interest share — lands at month 243, about year 20.
What extra payments change
Because the schedule front-loads interest, extra principal paid early retires the highest-interest dollars. On the same $400,000 loan at 7.03%: the baseline pays $960,939 total over 360 months, $560,939 of it interest. With +$200/mo, payoff lands at month 291 — 24.3 years, 5.7 years early — and total interest falls to $433,401: $127,537 less than the baseline, computed month by month including the smaller final payment.
The same $200/month, in schedule terms: it buys 69 months off the back of the loan, where the interest share would have been at its highest, without changing the payment structure — the extra payment is entirely principal from month one. The calculator above renders both columns side by side, so the saved-interest figure is visible as a schedule difference, not a promise. The payoff calculator runs the same math for lump-sum and biweekly variants. And if your down payment was under 20%, the same schedule decides when PMI ends — the when PMI auto-drops on your schedule guide ties the 78% cancellation rule to the amortization curve.
Term and rate: what they cost
Two comparisons, both computed on the same $400,000 principal. Term — the 15-year payment at 7.03% is $3,602.03 (35% higher than the 30-year's $2,669.27) and its total interest is $248,365 — 56% lower than the 30-year's $560,939. The schedule answer to “which is better” is not a recommendation — it is the two rows, and the note that the 15-year's higher required payment is the price of the interest savings.
Rate — at an illustrative 6.5% on the same 30-year, the payment is $2,528.27 (−$141/mo) and total interest $510,178 (−$50,761 over the term). Half a point is roughly $50,800 on this loan size — which is why refinance decisions anchor on rate spread, and why the schedule above renders at the rate you enter, not the PMMS default.
The tax model, as the calculators price it
Where amortization meets taxes: the mortgage-interest deduction benefit is credited only when itemizing beats the $32,200 standard deduction (2026, married filing jointly) with the $40,400 SALT cap (2026) — the constants in the rent-vs-buy model's tax model. Most households at these defaults do not itemize. Planning estimate, not tax advice.
FAQ
What is an amortization schedule?
A table that splits every mortgage payment into interest and principal for the life of the loan, showing the remaining balance after each payment. The split is set by the formula — interest is charged on the balance still outstanding — so the early years are mostly interest and the later years mostly principal.
Why is most of my early payment interest?
Because the interest bill is computed on the full remaining balance each month. Early on the balance is largest, so the interest share is largest (87% in year 1 of the worked example); as principal retires, the interest share falls and the principal share grows. It's the math of a fixed-rate loan, not a penalty.
How much interest do I pay over 30 years on a $400,000 mortgage?
At 7.03%, the computed total is $560,939 — more than the principal itself. That figure is the one the schedule makes concrete and the reason extra payments and shorter terms get attention.
Do extra payments actually shorten the loan?
Yes, mechanically. An extra $200/month on the example pays the loan off in 291 months (24.3 years) instead of 360, and reduces total interest by $127,537. The calculator renders the with-extras schedule so the payoff month and saved interest are visible as schedule rows.
What's the difference between amortization and a simple-interest loan?
Amortizing loans recalculate interest monthly on the declining balance inside a fixed payment. Simple-interest loans charge on the outstanding balance differently and can shift the payoff date — worth knowing when comparing non-standard lender products; the schedule calculator covers conventional fixed-rate amortization.
Is a 15-year mortgage cheaper than a 30-year?
In total interest, yes — the 15-year at 7.03% pays $248,365 in interest versus $560,939 on the 30-year. The trade is the monthly payment: $3,602 vs $2,669. The schedule shows both rows; which fits is a payment-affordability decision, not an arithmetic one.
Sources & method
- Freddie Mac Primary Mortgage Market Survey (PMMS) — 7.03% 30-yr fixed, week of September 24, 2026 — freddiemac.com/pmms (re-check on publish; comparative rate 6.5% labeled illustrative)
- Method: all figures computed with the standard fully-amortizing formulas (the same
monthlyPandI/remainingBalancemath this calculator runs in your browser) — every number is formula output, not an estimate - Companion tools: mortgage payoff calculator (extra-payment variants) · mortgage payment calculator · refinance calculator (rate-spread math)
This page explains what the schedule shows; it does not advise borrowing, prepaying, or refinancing. [As-of September 24, 2026] on the PMMS snapshot; re-check before relying on the snapshot figures.