Loan Calculator
Use the Loan Calculator when you want to see how the figures change under a particular set of assumptions. Enter the values you know, review the result and compare a second scenario if you are weighing an option.
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Last reviewed January 15, 2026 — see our editorial & accuracy policy.
Method: Fixed-rate payments use the standard amortization formula; total interest = (payment × number of payments) − principal.
How it works
Loans use the same amortization formula as a mortgage:
Payment = P × [ r(1 + r)n ] ÷ [ (1 + r)n − 1 ]
Here P is the loan amount, r is the monthly rate (annual rate ÷ 12) and n is the total number of monthly payments. Total interest is simply the total of all payments minus the amount borrowed.
How to use the Loan Calculator
Enter the values requested by the tool and start with one realistic example. Read the result together with its unit or label, then change one input at a time if you want to compare options. Keeping a note of the original figures makes the calculation easier to check later.
Use the result as a planning estimate rather than a quote or guarantee. Rates, fees, tax rules and personal circumstances can change the final figure.