Interest Rate Impact Calculator

Even a 1% difference in interest rate can cost tens of thousands over a loan term. See exactly what a rate change means for your monthly payment, total interest, and total amount repaid.

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How interest rate affects your loan

Interest rate has an outsized effect on what a loan really costs. This calculator shows how changing the rate moves both your monthly payment and the total interest you pay over the full term.

Because interest compounds over years, even a fraction of a percent makes a real difference on a large or long loan — which is exactly why shopping around for a better rate, or improving your credit before applying, can be so worthwhile.

Estimates only, and not financial advice. Figures assume a fixed interest rate — always check your loan or card agreement for the exact terms.

Common questions about interest rates

How much does the interest rate affect my payment?

More than most people expect, especially on big or long loans. A higher rate raises both your monthly payment and the total interest — and the effect grows the larger the balance and the longer the term.

Why does a small rate change matter so much?

Because interest is charged repeatedly over the whole term, a small percentage difference compounds into a large sum over many years. On a mortgage, half a percent can mean tens of thousands over the life of the loan.

Is it worth shopping around for a lower rate?

Almost always. Even a modest rate reduction can save a significant amount over the term, so comparing lenders — and improving your credit score before applying — is usually well worth the effort.

How does the rate affect total cost over the loan?

A higher rate means more of every payment goes to interest rather than principal, so you pay more in total and the balance falls more slowly. Lower rates flip both effects in your favour.