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Amortization schedule calculator

Amortization calculator: payment, dated schedule and yearly totals for monthly, biweekly or weekly payments, with principal and interest in each.

更新日 検証済みの例：6

$
%
= 2026-10-29
その他の設定
Most US loans charge the annual rate ÷ payments per year. A Canadian mortgage must state its rate calculated yearly or half-yearly, not in advance (Interest Act, section 6).
$
試す
支払額
$per month
支払額: $1,580.17 per month
小数点以下の桁数：2；最も近い値へ、等距離なら末尾が偶数の値へ
Number of payments
360
Total interest
$318,861.22
Total of all payments
$568,861.22
Last payment
Friday, 29 September 2056
Rate per payment period
0.541667%
Effective annual rate
6.6972%

360 payments of $1,580.17 per month repay $250,000.00 by September 2056 with $318,861.22 of interest, 56.1% of everything paid. The first payment is $1,354.17 interest and $226.00 principal; principal first exceeds interest in payment 233.

Principal and interest in each payment

$0$500$1,000$1,500203020352040204520502055Payment datePayment 233
InterestPrincipal

Principal and interest paid each calendar year

$0$5,000$10K$15K$20K20262029203220352038204120442047205020532056
PrincipalInterest

Balance owed

$0$100K$200K203020402050Date
返済予定表 行数：360
No.Date支払額元金利息Interest to date残高
1Thursday, 29 October 2026$1,580.17$226.00$1,354.17$1,354.17$249,774.00
2Sunday, 29 November 2026$1,580.17$227.23$1,352.94$2,707.11$249,546.77
3Tuesday, 29 December 2026$1,580.17$228.46$1,351.71$4,058.82$249,318.31
4Friday, 29 January 2027$1,580.17$229.70$1,350.47$5,409.29$249,088.61
5Sunday, 28 February 2027$1,580.17$230.94$1,349.23$6,758.52$248,857.67
6Monday, 29 March 2027$1,580.17$232.19$1,347.98$8,106.50$248,625.48
7Thursday, 29 April 2027$1,580.17$233.45$1,346.72$9,453.23$248,392.04
8Saturday, 29 May 2027$1,580.17$234.71$1,345.46$10,798.68$248,157.32
9Tuesday, 29 June 2027$1,580.17$235.98$1,344.19$12,142.87$247,921.34
10Thursday, 29 July 2027$1,580.17$237.26$1,342.91$13,485.78$247,684.07
11Sunday, 29 August 2027$1,580.17$238.55$1,341.62$14,827.40$247,445.53
12Wednesday, 29 September 2027$1,580.17$239.84$1,340.33$16,167.73$247,205.69
13Friday, 29 October 2027$1,580.17$241.14$1,339.03$17,506.76$246,964.55
計算方法 S

  1. Rate per payment period

    i=6.5%12=0.541667%i = \frac{6.5\%}{12} = 0.541667\%

  2. 支払額

    A=L i (1+i)360(1+i)360−1=1,580.17A = \frac{L\,i\,(1+i)^{360}}{(1+i)^{360}-1} = 1{,}580.17

    n = 360 months × 12 ÷ 12 = 360 payments. Shown rounded to cents; the schedule uses the unrounded payment and the last payment clears any sub-cent residual.

  3. Total interest

    interest=568,861.22−250,000=318,861.22\text{interest} = 568{,}861.22 - 250{,}000 = 318{,}861.22

    All payments minus the loan: 360 payments, the last on 2056-09-29.

  4. Effective annual rate

    (1+i)12−1=6.6972%(1 + i)^{12} - 1 = 6.6972\%

Amortization schedule calculatorについて

An amortization schedule splits every loan payment into interest and principal. Each period's interest is the balance times the rate per period, and the rest of the fixed payment reduces the balance, so the interest share falls with every payment. The payment is L × i × (1 + i)^n ÷ ((1 + i)^n − 1), where L is the loan, i the rate per period and n the number of payments.

With the defaults, 250,000 at 6.5% for 30 years, the payment is 1,580.17 a month and interest totals 318,861.22. The first payment is 1,354.17 of interest and only 226.00 of principal; principal overtakes interest at payment 233. Paying half the monthly amount every two weeks (accelerated biweekly) ends the loan after 628 payments, about 24.2 years, and saves 73,434.82 of interest.

The rate is fixed and every payment is the same, apart from a last payment that clears the remaining cents. Biweekly and weekly rates are the annual rate ÷ 26 or ÷ 52 unless you choose another compounding under More options.

計算例

200,000 at 6% for 15 years

Loan amount
200,000
Interest rate (per year)
6%
Loan term
15
Term in
年
Payment frequency
Monthly
First payment date
2026-01-01
Table shows
Every payment
Interest compounds
With each payment
Extra with every payment
0
支払額
1,687.71 per month
Number of payments
180
Total interest
103,788.46
Total of all payments
303,788.46
Last payment
2040-12-01

照合元：Calculator.net amortization calculator, published default output: 1,687.71 a month, 103,788.46 total interest

10,000 at 8% over 10 months

Loan amount
10,000
Interest rate (per year)
8%
Loan term
10
Term in
か月
Payment frequency
Monthly
First payment date
in 1 month
Table shows
Every payment
Interest compounds
With each payment
Extra with every payment
0
支払額
1,037.03 per month
Number of payments
10

照合元：Microsoft PMT function documentation: =PMT(8%/12, 10, 10000) returns ($1,037.03)

Biweekly payments sized to a 15-year term

Loan amount
200,000
Interest rate (per year)
6%
Loan term
15
Term in
年
Payment frequency
Biweekly
First payment date
2026-01-01
Table shows
Every payment
Interest compounds
With each payment
Extra with every payment
0
支払額
778.30 every 2 weeks
Number of payments
390
Total interest
103,536.93
Interest saved compared with monthly payments
251.53
Last payment
2040-11-29

照合元：Python decimal: annuity at 6%/26 over 390 periods; last payment 389 × 14 days after 2026-01-01

Canadian mortgage: 5% compounded half-yearly

Loan amount
300,000
Interest rate (per year)
5%
Loan term
25
Term in
年
Payment frequency
Monthly
First payment date
in 1 month
Table shows
Every payment
Interest compounds
Twice a year (Canada)
Extra with every payment
0
支払額
1,744.81 per month
Effective annual rate
5.0625%
Total interest
223,444.49
Rate per payment period
0.412392%

照合元：Python decimal: monthly rate (1.025)^(1/6) − 1, annuity over 300 months; effective rate 1.025² − 1

よくある質問

How do you calculate an amortization schedule?

Work out the fixed payment, then repeat three steps for every period: interest = balance × periodic rate, principal = payment − interest, new balance = balance − principal. For 250,000 at 6.5% over 30 years the payment is 1,580.17; month 1 interest is 250,000 × 6.5% ÷ 12 = 1,354.17, principal is 226.00 and the balance falls to 249,774.00. Excel's PMT, IPMT and PPMT functions give the same figures.

Why does most of an early mortgage payment go to interest?

Interest is charged on the balance still owed, and the balance is largest at the start. On 250,000 at 6.5% over 30 years, 1,354.17 of the first 1,580.17 payment is interest. The principal part grows each month and first exceeds the interest part at payment 233, in year 20. Extra payments move that point earlier because they cut the balance directly.

Do biweekly payments save interest?

Only the accelerated kind saves much. A biweekly payment sized to finish on the original 30-year term, 728.97 on 250,000 at 6.5%, saves 268.06 against monthly payments. Paying half the monthly payment, 790.09, every two weeks makes 26 half-payments, the same as 13 monthly payments a year; that ends the loan after about 24.2 years and saves 73,434.82.

How much interest does a 15-year loan save over a 30-year loan?

Borrowing 250,000 at 6.5%, a 30-year loan costs 1,580.17 a month and 318,861.22 of interest; over 15 years the payment rises to 2,177.77 and interest falls to 141,998.31, a saving of 176,862.91 at the same rate. Fifteen-year rates are lower in practice: Freddie Mac's survey of September 24, 2026, averaged 6.42% for 15-year and 7.03% for 30-year fixed loans.

How are Canadian mortgage payments calculated?

Canada's Interest Act (section 6) requires a mortgage to state its rate calculated yearly or half-yearly, not in advance, so the monthly rate is the equivalent of the half-yearly rate: (1 + 5% ÷ 2)^(1/6) − 1 = 0.41239% for a 5% mortgage. On 300,000 over 25 years that gives 1,744.81 a month, against 1,753.77 if the 5% compounded monthly. Choose "Twice a year (Canada)" under More options.

「Amortization schedule calculator」の精度はどのくらいですか？

精度は入力値と計算方法の前提に依存します。十進演算には有効数字50桁を使いますが、推定、数値計算手法、元データの精度はそれより低い場合があります。表示の丸め処理でこれらの制約がなくなるわけではありません。 独立した出典の解答と照合した計算例：6。 例えば、「200,000 at 6% for 15 years」はCalculator.net amortization calculator, published default output: 1,687.71 a month, 103,788.46 total interestと照合しています。

この計算方法の出典は何ですか？

Microsoft Excel PMT function (payment for a loan); Interest Act (Canada), R.S.C. 1985, c. I-15, section 6 — mortgage interest compounded half-yearly or yearly; Freddie Mac Primary Mortgage Market Survey (weekly 30-year and 15-year fixed rates); Consumer Financial Protection Bureau — How does paying down a mortgage work?.

この計算機について

A=L i (1+i)n(1+i)n−1,i={j/pcompounding with each payment(1+j/m)m/p−1compounding m times a yearA = \frac{L\,i\,(1+i)^n}{(1+i)^n - 1},\qquad i = \begin{cases} j/p & \text{compounding with each payment} \\ (1 + j/m)^{m/p} - 1 & \text{compounding } m \text{ times a year} \end{cases}

出典

  1. Microsoft Excel PMT function (payment for a loan)
  2. Interest Act (Canada), R.S.C. 1985, c. I-15, section 6 — mortgage interest compounded half-yearly or yearly
  3. Freddie Mac Primary Mortgage Market Survey (weekly 30-year and 15-year fixed rates)
  4. Consumer Financial Protection Bureau — How does paying down a mortgage work?

計画の参考用です。金融機関、税務当局、市場は独自の丸め方、手数料、規則を適用します。契約などの前に該当機関へ金額を確認してください。

出典と照合済み

この計算機には、独立した出典の解答を使った計算例が 6 件あります。テストに組み込まれており、ここでも実行できます。

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