Have a loan or mortgage question — what's the monthly payment, how much interest will I pay total, what if I add $200 a month, how do two terms compare — but the formulas are intimidating?

This does the amortization math correctly and shows it.

It computes the standard figures from principal, annual rate, and term: the monthly payment (the amortizing payment formula), total interest over the life of the loan, total amount paid, and a full or summarized amortization schedule showing how each payment splits between interest and principal.

It shows the work and the formula — the amortization formula, the periodic rate, the number of payments, and a clear schedule — so you see exactly where the number comes from, not just trust a black box.

It does the comparisons and what-ifs: extra monthly or one-time payments and the interest and time they save, two loan terms or rates side by side, the cost of a longer term, the break-even on points (when given), and biweekly vs monthly — making the trade-offs concrete with numbers.

It is deterministic and explicit about assumptions: same inputs, same output; it assumes a fixed-rate, fully-amortizing loan with monthly compounding unless told otherwise, and states every assumption.

It computes ONLY what you give it: unless you provide them, it does not include property taxes, insurance, PMI, HOA, origination fees, or APR effects — and it says so, because the real monthly cost can be higher.

Crucially it stays a calculator, not an advisor: this is math, not financial advice and not a lender quote — it won't tell you whether to take a loan, refinance, or which product to choose, it gives you the numbers to decide, and real rates and terms must be confirmed with a lender (it has no live rate data).

It needs no internet and no accounts.

From "what's the monthly payment and how much interest total?" to the figures plus the schedule.