About CD Calculator

We build free, precise, and transparent financial tools that help everyday savers make smarter decisions about their money.

Our Mission

Certificates of Deposit are one of the safest ways to grow your savings — but understanding the real return after taxes, inflation, and penalties is harder than it should be. CD Calculator exists to make that math instant, accurate, and honest.

Every tool on this site is free to use, requires no sign-up, and runs entirely in your browser. We never collect, store, or transmit your financial data.

Our Methodology

All calculations use industry-standard compound interest formulas, computed with Decimal.js for arbitrary-precision arithmetic. This means no floating-point rounding errors in your money — every figure is exact.

The core formula we use is:

A = P × (1 + r/n)^n×t
where A = maturity value, P = principal, r = annual rate, n = compounding periods per year, t = years

For early withdrawal penalties, we use the industry-standard simple interest method: Penalty = P × (r/12) × penalty months. You can verify every number we produce against any other reputable calculator.

How We Make Money

CD Calculator is free because some of the links on our CD Rates page are affiliate links. If you open an account through one of these links, we may earn a commission at no extra cost to you.

This never influences our rate rankings. We list banks by APY first, not by whether they pay us. Our editorial content is independent of our affiliate relationships.

Who We Are

CD Calculator is an independent project built by a small team of developers and personal finance enthusiasts. We are not affiliated with any bank or financial institution.

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