Amortization Calculator: Payment, Interest & Schedule

What does a $1,896.20 payment mean?

It means a $300,000 loan at 6.5% over 30 years costs $1,896.20 every month for 360 months, and $382,633.47 of interest on top of the $300,000 borrowed — $682,633.47 in total. The payment, the total interest and the total paid are three outputs, never the same number — the payment is what leaves your account each month, the total interest is what the loan costs you, and the total paid is what the loan costs you in all.

Three things to check before you trust the number

The first year is mostly interest. The first payment is $1,625.00 of interest and only $271.20 of principal, and after 12 payments the balance is still $296,646.82. If your balance barely moves in the first year, the loan is working as it should — it is not a mistake.

A shorter term costs more a month but saves a fortune. The same $300,000 at 6.5% over 15 years costs $2,613.32 a month but the total interest is only $170,397.98 — $212,235.49 less. Compare loans by their total interest, never by their payment alone, when the terms differ.

The rate is what the loan costs, not the payment. A 1.5-point rise in the rate, from 6.5% to 8%, lifts the payment from $1,896.20 to $2,201.29 a month and the total interest from $382,633.47 to $492,465.74. A small rate difference is a large money difference over 30 years.

Worked example

On the defaults: $300,000 loan; 6.5% APR; 30 years.

1. Monthly rate: 6.5% ÷ 12 = 0.541667% a month.
2. Number of payments: 30 × 12 = 360.
3. Monthly payment: $300,000 × 0.00541667 × (1.00541667)³⁶⁰ ÷ ((1.00541667)³⁶⁰ − 1) = $1,896.20.
4. Total paid: $1,896.20 × 360 = $682,633.47.
5. Total interest: $682,633.47 − $300,000 = $382,633.47.
6. First payment: $300,000 × 0.541667% = $1,625.00 of interest, so $271.20 of principal, leaving a balance of $299,728.80.
7. Largest loan for a $2,000 payment: $316,421 — at $316,421 the payment is $2,000.00 unrounded 1999.995961, and at $316,422 it is $2,000.00 unrounded 2000.002281.
8. Largest loan for $300,000 of interest: $235,212 — at $235,212 the total interest is $299,999.94, and at $235,213 it is $300,001.22.

The first year of the schedule, payment by payment

After 12 payments you have paid $19,401.27 of interest and $3,353.18 of principal, and the balance is $296,646.82. The first payment is $1,625.00 of interest and only $271.20 of principal — the interest falls a little every month and the principal rises a little, until the last payment is almost all principal.

Every branch, checked

• Loan $200,000: Loan $200,000: Monthly payment $1,264.14; total interest $255,088.98; total paid $455,088.98. A smaller loan at the same rate and term, so a smaller payment — $1,264.14 a month, $255,088.98 of interest.
• Loan $500,000: Loan $500,000: Monthly payment $3,160.34; total interest $637,722.44; total paid $1,137,722.44. A bigger loan at the same rate and term, so a bigger payment — $3,160.34 a month, $637,722.44 of interest.
• APR 5%: APR 5%: Monthly payment $1,610.46; total interest $279,767.35; total paid $579,767.35. A lower rate at the same loan and term, so a smaller payment — $1,610.46 a month, $279,767.35 of interest.
• APR 8%: APR 8%: Monthly payment $2,201.29; total interest $492,465.74; total paid $792,465.74. A higher rate at the same loan and term, so a bigger payment — $2,201.29 a month, $492,465.74 of interest.
• Term 15 years: Term 15 years: Monthly payment $2,613.32; total interest $170,397.98; total paid $470,397.98. Half the term costs $717.12 more a month but saves $212,235.49 of interest.
• Term 20 years: Term 20 years: Monthly payment $2,236.72; total interest $236,812.66; total paid $536,812.66. Ten years shorter than the default costs $340.52 more a month but saves $145,820.81 of interest.
• Term 10 years: Term 10 years: Monthly payment $3,406.44; total interest $108,772.72; total paid $408,772.72. A third of the term costs $1,510.24 more a month but saves $273,860.75 of interest.
• Loan $100,000: Loan $100,000: Monthly payment $632.07; total interest $127,544.49; total paid $227,544.49. A third of the loan at the same rate and term, so a third of the payment — $632.07 a month.
• APR 0%: APR 0%: Monthly payment $833.33; total interest $0.00; total paid $300,000.00. No interest at all — the payment is the loan divided by 360 payments, $833.33 a month.
• Term 25 years: Term 25 years: Monthly payment $2,025.62; total interest $307,686.45; total paid $607,686.45. Five years shorter than the default costs $129.42 more a month but saves $74,947.02 of interest.

The reverses, worked backwards

• Largest loan for the payment to STAY at or below $2,000: $316,421 — at $316,421 the figures are Monthly payment $2,000.00 (unrounded 1999.995961); total interest $403,577.55 (unrounded 403577.545822); total paid $719,998.55; at the lower neighbor the figures are Monthly payment $2,000.00 (unrounded 2000.002281); total interest $403,578.82 (unrounded 403578.821267); total paid $720,000.82; at the upper neighbor the figures are Monthly payment $1,999.99 (unrounded 1999.989640); total interest $403,576.27 (unrounded 403576.270377); total paid $719,996.27 — verdict: STEP.
• Largest APR for the payment to STAY at or below $1,800: 6.00% APR — at 6.00% APR the figures are Monthly payment $1,798.65 (unrounded 1798.651575); total interest $347,514.57 (unrounded 347514.567165); total paid $647,514.57; at the lower neighbor the figures are Monthly payment $1,800.58 (unrounded 1800.580786); total interest $348,209.08 (unrounded 348209.083060); total paid $648,209.08; at the upper neighbor the figures are Monthly payment $1,796.72 (unrounded 1796.723272); total interest $346,820.38 (unrounded 346820.377881); total paid $646,820.38 — verdict: STEP.
• Longest term where the payment still stays at or above $2,000: 25 years — at 25 years the figures are Monthly payment $2,025.62 (unrounded 2025.621484); total interest $307,686.45 (unrounded 307686.445213); total paid $607,686.45; at the lower neighbor the figures are Monthly payment $2,059.63 (unrounded 2059.627986); total interest $293,172.86 (unrounded 293172.860020); total paid $593,172.86; at the upper neighbor the figures are Monthly payment $1,994.75 (unrounded 1994.753417); total interest $322,363.07 (unrounded 322363.066117); total paid $622,363.07 — verdict: STEP.
• Largest loan for the total interest to STAY at or below $300,000: $235,212 — at $235,212 the figures are Monthly payment $1,486.70 (unrounded 1486.699839); total interest $299,999.94 (unrounded 299999.942191); total paid $535,211.94; at the lower neighbor the figures are Monthly payment $1,486.69 (unrounded 1486.693519); total interest $299,998.67 (unrounded 299998.666746); total paid $535,209.67; at the upper neighbor the figures are Monthly payment $1,486.71 (unrounded 1486.706160); total interest $300,001.22 (unrounded 300001.217635); total paid $535,214.22 — verdict: STEP.
• Largest APR for the total interest to STAY at or below $400,000: 6.74% APR — at 6.74% APR the figures are Monthly payment $1,943.80 (unrounded 1943.800541); total interest $399,768.19 (unrounded 399768.194854); total paid $699,768.19; at the lower neighbor the figures are Monthly payment $1,941.81 (unrounded 1941.807631); total interest $399,050.75 (unrounded 399050.746992); total paid $699,050.75; at the upper neighbor the figures are Monthly payment $1,945.79 (unrounded 1945.794290); total interest $400,485.94 (unrounded 400485.944294); total paid $700,485.94 — verdict: STEP.
• Longest term for the total interest to STAY at or below $200,000: 17 years — at 17 years the figures are Monthly payment $2,433.36 (unrounded 2433.363315); total interest $196,406.12 (unrounded 196406.116243); total paid $496,406.12; at the lower neighbor the figures are Monthly payment $2,517.23 (unrounded 2517.225797); total interest $183,307.35 (unrounded 183307.353079); total paid $483,307.35; at the upper neighbor the figures are Monthly payment $2,359.68 (unrounded 2359.683861); total interest $209,691.71 (unrounded 209691.713936); total paid $509,691.71 — verdict: STEP.

What the defaults assume

The defaults are a $300,000 loan at 6.5% over 30 years, with the same payment every month and no extra payments, no fees and no taxes — the payment is principal and interest only. They are a starting point, not a benchmark: a mortgage, a car loan and a personal loan have very different rates and terms, and the right loan for you is the one whose payment you can afford and whose total interest you can accept. Change the three numbers to your own and the calculator recomputes instantly. The first year is mostly interest — it is not a mistake, it is how amortization works: the interest is charged on the balance, and the balance is largest at the start.

These notes repeat in every explainer section because this page is built to be read start to finish: the defaults are one loan’s numbers, not a standard; the first year is mostly interest; a shorter term costs more a month but saves a fortune in interest; and the rate is what the loan costs, not the payment.

Output · formula · meaning

Who uses this

• A homebuyer who wants to know the monthly payment on a $300,000 mortgage before making an offer.
• A borrower comparing two loans who wants the total interest on each, not just the payment.
• A homeowner who wonders why the balance barely moved after a year of payments.
• A student who needs the amortization formula worked step by step for a finance assignment.

Accuracy & limitations

The calculator does the arithmetic exactly — the payment is the loan times the monthly rate times the compounding factor divided by the factor minus one, the total paid is the payment times the number of payments, and the total interest is the total paid minus the loan — and every figure on this page is checked against an independent model. What it cannot do is predict your loan: a real mortgage adds taxes, insurance, PMI and HOA on top of the payment, and an adjustable rate changes the payment when the rate changes. It also assumes the same payment every month with no extra payments — an extra payment shortens the loan and saves interest, and the loan-payoff-calculator page works that out. And the payment is $2,000.00 unrounded 1999.995961 at a $316,421 loan and $2,000.00 unrounded 2000.002281 at $316,422 — both display as $2,000.00, so the page prints the unrounded figure so the rounding does not mislead you.

Cite this calculator

Monthly payment = loan amount × monthly rate × (1 + monthly rate)^payments ÷ ((1 + monthly rate)^payments − 1); total paid = payment × payments; total interest = total paid − loan amount. On the defaults — $300,000 loan, 6.5% APR, 30 years — the payment is $1,896.20 a month, the total interest is $382,633.47 and the total paid is $682,633.47. First year: $19,401.27 of interest, $3,353.18 of principal, balance $296,646.82. Largest loan for a $2,000 payment: $316,421. Largest APR for a $1,800 payment: 6.00%. Longest term for a $2,000 payment: 25 years. Largest loan for $300,000 of interest: $235,212. Largest APR for $400,000 of interest: 6.74%. Longest term for $200,000 of interest: 17 years. Source: Bright Side Kit, brightoolbox.com.

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