What it does
The mortgage calculator works out the monthly cost of a fixed-rate home loan:
- Monthly payment: the principal and interest, plus a twelfth of the yearly property tax and home insurance, for example 2,522.62 on a 400,000 home with 20% down at 6.5% over 30 years, with 4,800 tax and 1,200 insurance a year.
- Down payment and loan amount: 80,000.00 and 320,000.00 in that example.
- Totals: the total interest and the total of all principal and interest payments, plus the last payment when rounding makes it differ.
- Repayment schedule: each year or each month, with the payment, how much of it is principal and how much is interest, and the balance left.
The result updates as you type. It calculates; it doesn’t compare lenders or loans.
How to use it
- Type the home price and the down payment as a percentage of it.
- Type the yearly interest rate and the term in years.
- Under More options, type the yearly property tax and home insurance, if you want them in the payment, and choose a schedule by year or by month.
- Select Copy result for the payment and totals, or Copy table for the schedule, ready to paste into a spreadsheet.
The calculator remembers your numbers and choices on this device, so they’re there the next time you open the page.
How it’s calculated
The down payment is the price times the percentage, rounded half up to the cent, and the loan amount P is the price minus the down payment. The monthly rate r is the yearly rate divided by 1,200, so 6.5% a year is r = 0.00541667. With n monthly payments (12 for each year of the term):
EMI = P × r × (1 + r)^n ÷ ((1 + r)^n − 1)
For 320,000 at 6.5% over 360 months, that’s 2,022.62. At 0%, it is P ÷ n. The monthly payment adds the yearly property tax ÷ 12 and the yearly home insurance ÷ 12, each rounded half up to the cent: 2,022.62 + 400.00 tax + 100.00 insurance = 2,522.62.
Every amount is in whole cents. Each month’s interest is the balance × r, rounded half up, and the rest of the payment reduces the balance. The last payment is the balance left plus its interest, so the principal parts add up to the loan amount exactly. Total interest is the total of payments minus the loan amount.
The calculation assumes a fixed rate for the whole term, one payment at the end of each month, and tax and insurance that stay the same each year. PMI, HOA fees, closing costs and lender fees aren’t included.
Good to know
- The home price can be from 1,000 to 1,000,000,000,000, and is rounded to whole cents. The down payment can be from 0% to 99%, in steps of 0.01.
- The rate can be from 0% to 100% a year, in steps of 0.01. The term is a whole number of years from 1 to 50, so the schedule has at most 600 monthly payments.
- Property tax and home insurance can each be from 0 to 1,000,000,000 a year. At 0 they’re left out of the result.
- On a small loan over a long term, rounding the payment up to the next cent can repay it before the term ends, and the result notes the early payoff.
- No currency is assumed: the amounts are in whatever currency you type.
Privacy
Everything is calculated in your browser, on your device. Nothing you type is uploaded. Only your numbers and choices are kept, in this browser’s storage, so the page can show them again.