30 year loan calculator

This is a 30 year loan calculator that works the schedule a broker or loan officer hands a client, from the principal, the rate and any extra monthly payment. Principal times the payment per thousand for the rate over 30 years is the monthly payment of principal and interest; principal times the annual rate over twelve is the first month's interest, and the payment less that is the first month's principal; the payment times 360 is the total paid over the term, and that less the principal is the total interest; the payment plus the extra is the monthly outlay. The per-thousand table is the standard amortisation formula for rates in eighths from 3.000 to 12.000; the worked example rounds Freddie Mac's 30-year survey average of 6.71% as of September 3, 2026 to 6.75%, and the client's quote replaces it. Free, on the page, no account; the paid plan keeps every scenario and schedule against the client.

The payment, from the table

$300,000 at 6.75% over 30 years is $1,945.80 a month of principal and interest. The table carries the payment per thousand for every eighth from 3.000 to 12.000, which is the range a quote lands in; enter the rate to the nearest eighth and the worksheet multiplies. Taxes, insurance and any mortgage insurance sit outside the figure, as they do on the schedule.

The first month's split

$300,000 at 6.75% is $1,687.50 of interest in the first month, so $258.30 of the first payment is principal. The split is what a client asks about most and what a lender's calculator rarely shows; the worksheet returns both figures so the conversation starts from them.

The term, the interest and the extra payment

360 payments of $1,945.80 is $700,488, of which $400,488 is interest on the worked example. An extra $100 a month makes the outlay $2,045.80 and goes to principal, shortening the term; the exact months saved need the full schedule, which the paid plan keeps against the client with the comparison.