Mortgage / Loan Calculator
Enter loan amount, rate, and term to estimate your monthly payment and total interest with equal principal-and-interest amortization.
Estimated using standard amortization — each payment stays the same but the principal/interest mix shifts over time. Actual figures depend on your lender.
How is a loan payment calculated?
Most mortgages and installment loans use "amortized" payments — the total monthly payment stays fixed for the life of the loan, but the mix shifts over time: early payments are mostly interest, later payments are mostly principal. This keeps your monthly budget predictable even though the loan balance is shrinking unevenly.
The formula looks intimidating, but the idea is simple: it spreads the total principal plus interest evenly across every payment so each installment is identical. This tool runs the formula for you — just enter the loan amount, annual rate, and term.
Why loan term length changes the math so much
Stretching a loan from 15 to 30 years roughly cuts the monthly payment, which is why longer terms look appealing on the surface — but doubling the term doesn't just double the interest, it can more than double it, since the balance stays higher for longer and accrues interest against that higher balance for twice as many months. Running the same loan amount through this calculator at a few different term lengths side by side is often the fastest way to see the real tradeoff between monthly affordability and total cost.
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Common mistakes and interpretation
A lower monthly payment does not necessarily mean a cheaper loan. Extending the term can reduce monthly payments while increasing total interest. Compare the rate, total repayment, total interest, fees and term together rather than focusing on one number.
Practical use
For an actual borrowing decision, use the lender’s agreement and amortization schedule as the authoritative figures. Use this calculator to understand the numbers and prepare questions before discussing the loan with a financial institution.
Content check: 2026-09-12. This guide explains the calculator rather than promising a particular outcome; for formal decisions, use current official or provider documentation.
FAQ
What amortization method is used?
Equal principal-and-interest (fixed monthly payment). Early payments are interest-heavy; later payments are principal-heavy. Bank products may differ.
Why doesn’t this match my bank quote?
Fees, insurance, grace periods, rate type, and rounding rules often differ. Use the bank’s contract and amortization schedule for final numbers.
What rate should I enter?
Use the annual interest rate your lender quotes. Monthly-only rates need conversion first; results remain estimates.
Is my input saved?
No. Amount, rate, and term are calculated in your browser only.
Is this financial advice?
No. It is a planning estimate only.