Mortgage Calculator

Calculate the monthly payment on a level-payment or equal-principal mortgage, the total interest, and how much interest and principal you pay each year.

Loan amount

The amount you borrow for the home. Any down payment you put in yourself is not included.

Annual interest rate (%)

The yearly interest rate. The calculator charges one twelfth of it every month.

Term (years)

How long you take to repay, in whole years from 1 to 40. Many mortgages run for 25 or 30 years.

Repayment type

Level paymentsEqual principal

Level payments: the same monthly payment every month. Equal principal: the same part of the loan is repaid every month, so the payment goes down over time.

Monthly payment (first month)

$2,056.71

Level payments

Interest in the first year

$21,805

Total interest

$440,417

Total paid

$740,417

Interest and principal per year

Interest
Principal

Show the table

Year	Interest	Principal
1	$21,805	$2,875
2	$21,588	$3,093
3	$21,355	$3,326
4	$21,103	$3,577
5	$20,833	$3,847
6	$20,543	$4,138
7	$20,231	$4,450
8	$19,895	$4,786
9	$19,533	$5,147
10	$19,145	$5,536
11	$18,727	$5,954
12	$18,277	$6,403
13	$17,794	$6,887
14	$17,274	$7,406
15	$16,715	$7,966
16	$16,114	$8,567
17	$15,467	$9,214
18	$14,771	$9,909
19	$14,023	$10,657
20	$13,219	$11,462
21	$12,353	$12,327
22	$11,423	$13,258
23	$10,422	$14,259
24	$9,346	$15,335
25	$8,188	$16,493
26	$6,943	$17,738
27	$5,604	$19,077
28	$4,164	$20,517
29	$2,615	$22,066
30	$949	$23,732

Remaining balance by year

Remaining balance

Show the table

Year	Remaining balance
0	$300,000
1	$297,125
2	$294,032
3	$290,706
4	$287,129
5	$283,282
6	$279,144
7	$274,694
8	$269,908
9	$264,761
10	$259,225
11	$253,271
12	$246,868
13	$239,982
14	$232,575
15	$224,610
16	$216,043
17	$206,829
18	$196,920
19	$186,262
20	$174,801
21	$162,473
22	$149,216
23	$134,957
24	$119,622
25	$103,129
26	$85,392
27	$66,315
28	$45,798
29	$23,732
30	$0

Total paid, split

Principal $300,000 40.5%
Interest $440,417 59.5%

Total $740,417

Please note: This is an example calculation, not financial advice. Personal circumstances, changes in rules and rates, and additional costs are not included. If in doubt, talk to a financial adviser.

The mortgage interest deduction, property taxes, insurance, fees and rate changes during the term are not included.

How this number is calculated

The blocks use your input. Change a value above and they update with it.

Step 1 · Number of months

Term (years)30 × Months per year12 =Number of months360

Step 2 · Monthly interest rate

Annual interest rate (%)7.3 ÷ Months per year12 =Monthly interest rate0.6083 %

Step 3 · Monthly payment (first month)

(Repayment type: Level payments) (becauseMonthly interest rate0.6083 % does not equal 0 ) Loan amount$300,000.00 × Monthly interest rate0.6083 % ÷ Per100 ÷ 1 − power ofMonthly growth factor1.0061 − Number of months360 =Monthly payment (first month)$2,056.71

Step 4 · Monthly payment (final month)

(Repayment type: Level payments) Monthly payment (first month)$2,056.71 =Monthly payment (final month)$2,056.71

Step 5 · Total interest

(becauseRepayment type1 (Level payments) equals 1 and Monthly interest rate0.6083 % greater than 0 ) Monthly payment (first month)$2,056.71 × Number of months360 − Loan amount$300,000.00 =Total interest$440,417

Step 6 · Total paid

Loan amount$300,000.00 + Total interest$440,417 =Total paid$740,417

How the calculation works

Calculate your monthly payment, the total interest and the total amount you pay back. Choose level payments or equal principal and see, year by year, how much of your money goes to interest, how much to principal and how the remaining balance comes down.

A mortgage is repaid in monthly installments of interest and principal. The interest for a month is the remaining balance times the monthly rate, one twelfth of the annual rate. With level payments (an annuity or standard fixed-rate mortgage) the payment is the same every month: at the start the balance is high and most of the payment is interest, later more and more goes to principal. With equal principal (a linear mortgage) the same amount is repaid every month, the loan amount divided by the number of months, so the interest and the payment go down a little every month. The calculator uses formulas that give the same result as working through the schedule month by month. Monthly payments are rounded to the cent; totals and yearly amounts to whole units of currency.

Formula

Monthly rate r = annual rate ÷ 12 ÷ 100, number of months n = term × 12. Level payments: payment = loan × r ÷ (1 − (1 + r)^−n), total interest = payment × n − loan. Equal principal: principal per month = loan ÷ n, first payment = loan ÷ n + loan × r, total interest = loan × r × (n + 1) ÷ 2. At 0% interest the payment is loan ÷ n.

Assumptions

The interest rate stays the same for the whole term; each month is charged one twelfth of the annual rate.
Each payment is made at the end of the month, with no extra or missed payments.
The mortgage interest deduction and other tax effects are not included: the payment is before tax.
Property taxes, insurance, mortgage insurance, closing costs and other fees are not included.
The loan is fully repaid by the end of the term; interest-only parts and balloon payments are not included.
Monthly payments are rounded to the cent; totals and yearly amounts to whole units of currency.

Example calculations

The button fills in the calculator above, so you can carry on from there.

Level payments over 30 years

Monthly payment (first month)
$1,432.25

Loan amount $300,000.00 · Annual interest rate (%) 4 · Term (years) 30 · Level payments
Level payments over 20 years

Monthly payment (first month)
$1,449.90

Loan amount $250,000.00 · Annual interest rate (%) 3.5 · Term (years) 20 · Level payments
Equal principal over 30 years

Monthly payment (first month)
$2,611.11

Loan amount $400,000.00 · Annual interest rate (%) 4.5 · Term (years) 30 · Equal principal

Frequently asked questions

What is the difference between level payments and equal principal?

With level payments (an annuity or standard fixed-rate mortgage) the monthly payment is the same every month. With equal principal (a linear mortgage) the same part of the loan is repaid every month, so the payment starts higher and goes down, and the total interest is lower. For 300,000 at 4% over 30 years the total interest is 215,609 with level payments and 180,500 with equal principal.

Why do I repay so little at the start?

Interest is charged on the remaining balance, which is highest at the start. On a level-payment mortgage of 300,000 at 4% over 30 years, 11,904 goes to interest and 5,283 to principal in the first year. In the last year it is 367 interest and 16,820 principal.

Is the monthly payment before or after tax?

Before tax. The calculator shows principal and interest only. The mortgage interest deduction, property taxes, insurance and fees are not included, so the amount actually paid each month can be different.

What if the interest rate changes?

The calculator uses one rate for the whole term. In practice a rate is often fixed for a set period and can change after that, and the payment changes with it. Entering a different rate shows the effect on the payment right away.

Are extra payments included?

No, the calculator follows the regular schedule. An extra payment lowers the remaining balance and with it the interest charged afterward. How much can be repaid early without a prepayment penalty depends on the terms of the loan.

How exact is the result?

The result is the same as working through the schedule month by month, with monthly payments rounded to the cent and totals to whole units. Lenders may round differently or charge interest per day, so their figures can differ slightly.

Sources and checks

Sources

Mortgage key terms | Consumer Financial Protection Bureau (opens in a new tab)consumerfinance.gov · accessed October 5, 2026
Monthly New Residential Sales, August 2026 | U.S. Census Bureau (opens in a new tab)census.gov · accessed October 6, 2026
30-Year Fixed Rate Mortgage Average in the United States (MORTGAGE30US) | FRED | St. Louis Fed (opens in a new tab)fred.stlouisfed.org · accessed October 6, 2026

How we check it

This calculator has 21 fixed checks: 13 calculations with a result that is fixed in advance, and 8 cases of invalid input that must be rejected. They all run automatically every time we publish; if one fails, the calculator does not go live.

See the calculations

Loan amount $300,000.00 · Annual interest rate (%) 4 · Term (years) 30 · Level payments → Monthly payment (first month) $1,432.25
Loan amount $300,000.00 · Annual interest rate (%) 4 · Term (years) 30 · Equal principal → Monthly payment (first month) $1,833.33
Loan amount $250,000.00 · Annual interest rate (%) 3.5 · Term (years) 20 · Level payments → Monthly payment (first month) $1,449.90
Loan amount $400,000.00 · Annual interest rate (%) 4.5 · Term (years) 30 · Equal principal → Monthly payment (first month) $2,611.11
Loan amount $120,000.00 · Annual interest rate (%) 0 · Term (years) 10 · Level payments → Monthly payment (first month) $1,000.00
Loan amount $120,000.00 · Annual interest rate (%) 0 · Term (years) 10 · Equal principal → Monthly payment (first month) $1,000.00
Loan amount $12,000.00 · Annual interest rate (%) 6 · Term (years) 1 · Level payments → Monthly payment (first month) $1,032.80
Loan amount $2,000,000.00 · Annual interest rate (%) 15 · Term (years) 40 · Level payments → Monthly payment (first month) $25,064.48
Loan amount $2,000,000.00 · Annual interest rate (%) 15 · Term (years) 40 · Equal principal → Monthly payment (first month) $29,166.67
Loan amount $200,619.00 · Annual interest rate (%) 4 · Term (years) 30 · Equal principal → Monthly payment (first month) $1,226.01

Changes

October 6, 2026: Separate default loan amounts and interest rates for the UK and the US, with official sources for both.
October 5, 2026: Clearer help texts for the fields. Sources added and content reviewed.
October 4, 2026: First version.

Last reviewed: October 6, 2026 · How we build and check our calculators