Loan Payment Calculator

The formula behind the number

This uses the standard amortizing-loan formula to estimate a fixed monthly payment from the principal, annual interest rate, and loan term — the same math behind most mortgage, auto, and personal loan payment schedules. "Amortizing" means each payment is the same fixed amount, but the split between interest and principal shifts over time — early payments are mostly interest, later ones are mostly principal, even though the total payment never changes.

It also breaks out total paid and total interest over the life of the loan, so you can see how much of a long-term loan is actually interest. Pure math, not financial advice — actual loan terms and fees vary by lender.

What this doesn't account for

This calculates a plain fixed-rate schedule with no extra payments. In reality, paying even a little extra toward principal each month — or making one extra payment a year — can cut years and a meaningful amount of interest off a long loan. That's not modeled here, but it's worth running separately if you're comparing loan offers or weighing payoff strategies.

Interest rate vs. APR

This calculator uses a single interest rate figure, but real loan offers are usually quoted with both a rate and an APR (annual percentage rate) — APR folds in certain fees and closing costs on top of the base interest rate, so it's almost always the slightly higher of the two numbers, and it's the fairer figure to use when comparing offers from different lenders, since one lender's low headline rate can hide higher fees that a bare rate comparison would miss. If you're comparing two real offers, running each one's APR (not its advertised rate) through this calculator gives the more honest side-by-side picture.

How term length trades off against total cost

Stretching the same loan over a longer term lowers the monthly payment but raises the total interest paid, since interest keeps accruing on the outstanding balance for longer — a $20,000 loan at 6.5% costs noticeably more in total interest spread over 7 years than over 5, even though the monthly payment is smaller. There's no universally right answer between the two; it's a genuine trade-off between monthly cash flow and total cost, worth running both term lengths through this calculator side by side before deciding.