Amortization Calculator
Generate the complete payment-by-payment schedule for any loan showing principal, interest, and remaining balance month by month from the first payment to the last.
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Enter your values above to see the results.
Tips & Notes
- ✓Always specify that extra payments go to principal only when submitting — some servicers apply them to future payments instead, which provides no benefit.
- ✓The first year of a 30-year mortgage at 7% directs only about 12% of each payment to principal — knowing this sets realistic expectations for early equity growth.
- ✓Bi-weekly payments instead of monthly result in 26 half-payments per year — equivalent to one free extra payment annually with no lifestyle change.
- ✓A single lump-sum extra payment in year 1 saves roughly 3-4 times more interest than the same payment in year 15 due to compounding effects.
- ✓Review your amortization schedule before refinancing — compare the full remaining interest on both loans, not just the new monthly payment.
- ✓Request a payoff statement from your lender before making a large extra payment — interest accrues daily and the exact payoff amount changes constantly.
Common Mistakes
- ✗Assuming that after 15 years on a 30-year loan you are halfway done — roughly 74% of the balance still remains at the midpoint in time.
- ✗Refinancing repeatedly into new 30-year loans, which resets the amortization clock and keeps you in the heavy-interest early years indefinitely.
- ✗Making extra payments without confirming they are applied to principal — misapplied payments help the servicer, not you.
- ✗Comparing a refinance offer by monthly payment alone without running the full amortization on both loans side by side.
- ✗Not checking the amortization schedule before signing — the total interest on a 30-year mortgage routinely exceeds the original loan amount.
- ✗Confusing remaining term with remaining balance — you can have 20 years left on a loan and still owe 85% of the original principal.
Amortization Calculator Overview
An amortization schedule is the full map of your loan from the first payment to the last. It reveals what most borrowers never discover: in the early years, the overwhelming majority of each payment goes to interest — not to reducing what you owe.
This calculator generates the complete schedule and shows precisely how extra payments compress the timeline and eliminate interest.
What each field means:
- Principal — the original loan amount you are repaying
- Rate — annual interest rate; used to calculate how much interest accrues each month on the remaining balance
- Years — total loan term; determines number of payments and the amortization curve
- Extra Payment — additional principal paid each month on top of the required payment
What your results mean:
- Base Monthly Payment — the required fixed payment to pay off the loan in the standard term
- Effective Monthly Payment — base payment plus your extra payment
- Total Interest Paid — all interest over the full term; compare with and without extra payments
- Payoff Time — exact months to full payoff; extra payments shorten this directly
- Interest Saved — total interest eliminated by your extra payment strategy
Example — $200,000 at 7.0% / 30 years:
Monthly payment: $1,331 Month 1: $1,167 interest (88%) + $164 principal (12%) — balance: $199,836 Month 60 (year 5): $1,125 interest + $206 principal — balance: $190,041 Month 180 (year 15): $1,025 interest + $306 principal — balance: $174,813 Month 264 (year 22): $661 interest + $670 principal — interest finally below 50% Total interest over 30 years: $279,016
EX: Extra payment impact on $200,000 at 7.0% / 30 years $0 extra: pays off in 360 months — total interest $279,016 $100 extra/month: pays off in 307 months — saves $45,613 interest $200 extra/month: pays off in 268 months — saves $75,397 interest $500 extra/month: pays off in 197 months — saves $131,856 interest Each $100 extra per month is worth roughly $45,000 in eliminated interest.
Principal vs interest by year — $200,000 at 7.0%:
| Year | Interest Paid | Principal Paid | Balance Remaining |
|---|---|---|---|
| Year 1 | $13,932 | $2,040 | $197,960 |
| Year 5 | $13,508 | $2,464 | $190,041 |
| Year 10 | $12,862 | $3,110 | $178,481 |
| Year 20 | $10,396 | $5,576 | $144,827 |
| Year 30 | $516 | — | $0 |
Extra payment savings — $200,000 at 7.0% / 30 years:
| Extra Payment | Interest Saved | Years Cut | New Payoff |
|---|---|---|---|
| $0 | — | — | 30 years |
| $100/month | $45,613 | 4 yr 5 mo | 25 yr 7 mo |
| $200/month | $75,397 | 7 yr 8 mo | 22 yr 4 mo |
| $500/month | $131,856 | 13 yr 7 mo | 16 yr 5 mo |
After 15 years of payments on a 30-year mortgage, most borrowers assume they are halfway done. They are not — at year 15, roughly 74% of the original balance still remains. The halfway point on the balance does not arrive until approximately year 21. This front-loading of interest is mathematically unavoidable, which is why extra payments applied early in the loan term eliminate interest at a rate far exceeding their face value.
Frequently Asked Questions
A complete table of every loan payment from first to last, showing for each payment: the payment number and date, total payment amount, the portion covering interest, the portion reducing principal, and the remaining balance after payment. This makes visible the gradual shift from mostly-interest to mostly-principal that defines every fixed-rate loan. Most borrowers who study their schedule for the first time are surprised by how slowly the balance falls in early years and how quickly it drops at the end.
Because interest is calculated on the remaining balance each month, and in early years that balance is still large. On a $200,000 mortgage at 7%, the first payment of $1,331 covers $1,167 in interest on the $200,000 balance, leaving only $164 to reduce the principal. As the balance gradually falls, the interest portion shrinks slightly each month, freeing more of the fixed payment for principal. This self-accelerating effect means the balance falls slowly for decades, then rapidly in the final years.
Substantially more than most people expect, especially when made early. On a $200,000 mortgage at 7% over 30 years, adding $200 extra per month saves $75,397 in interest and pays off the loan nearly 8 years early. That $200/month creates a guaranteed 7% annual return on every dollar of interest eliminated. The key is specifying extra payments go to principal only. Even irregular lump sums applied at any point save interest, though the compounding benefit is greatest in the first third of the loan term.
Standard amortization calculates interest on the remaining balance each period — early payments are mostly interest, later payments are mostly principal. Simple interest calculates interest only on the original principal, so each period the interest portion stays the same regardless of how much has been paid. Some auto loans use simple interest, meaning extra payments immediately reduce the balance on which future interest is calculated. Amortized loans have predictable fixed payments but front-load interest significantly in the early years.
Refinancing into a 15-year term typically saves a large amount in total interest but increases the monthly payment significantly. On a $200,000 remaining balance at 7%, a 15-year refinance at 6.5% results in roughly $1,742/month versus $1,331 on the original 30-year — but total interest drops dramatically. However, if refinancing resets the clock on a loan you are already 10 years into, you may pay more total interest even at a lower rate because you extend the total repayment period. Always compare the full amortization schedules, not just the monthly payments.
The amortization schedule shows the exact balance after every payment. For any payment number k of n total payments, the remaining balance is B = P x [(1+r)n - (1+r)k] / [(1+r)n - 1]. The simplest approach is requesting a payoff statement from your lender — this gives the exact balance including daily interest accrual, which is required for refinancing or early payoff. The figure often differs slightly from the scheduled balance due to payment timing and rounding differences.