Interest calculators reveal exactly how much your money grows — or costs — over time. Run the Compound Interest Calculator to watch returns build year over year, use the Simple Interest Calculator for straightforward loan estimates, check the Daily Interest Calculator for short-term costs, or discover what a credit card balance is really costing you each month with the Credit Card Interest Calculator.

Browse the Most Popular list to find the tools most savers and borrowers rely on, or switch to the Trending tab to see what is resonating this week. Every calculator is free, no login needed, and runs on any device.

  • Daily Interest Calculator
    Enter principal, annual interest rate, and number of days to get the daily rate, interest earned for the period, and total amount on a 365-day basis.
  • Interest Rate Calculator
    Calculate interest rates effortlessly with this Interest Rate Calculator. Input principal amount, interest rate, time, and compound frequency for accurate results. Optimize your financial planning today!
  • Annualized Return Calculator
    Free annualized return calculator: convert a holding period gain or loss into an equivalent yearly compound rate from beginning value, ending value, and days held.
  • Simple Interest Calculator (I = Prt)
    Solve the simple interest formula I = Prt for interest, principal, rate or time. Choose day-count basis (360 or 365), weeks, months, quarters or years.
  • CAGR (Compound Annual Growth Rate) Calculator
    Calculate Compound Annual Growth Rate (CAGR) from beginning and final values. Solve for CAGR%, periods, beginning, or final value in days, weeks, months, quarters or years.
  • Number of Payments (NPER) Calculator
    Calculate how many payments (NPER) it takes to pay off a loan from the present value, fixed payment amount, and interest rate. Free online tool.
  • Break-Even Interest Rate Calculator
    Compare taxable vs tax-free yields. Find the taxable equivalent yield a taxable bond must earn to beat a tax-free municipal bond at your tax rate.
  • Simple Interest Calculator
    Compute simple interest from principal, rate, and years. See interest earned and total amount instantly to plan loans or savings.
  • Annuity Calculator
    Calculate the future value and present value of an annuity from your payment, interest rate, and number of periods. Supports ordinary and annuity-due.
  • Compound Interest Calculator
    Enter principal, annual rate, years, and compounding (annual to daily) to get final amount and total interest earned—plan your savings growth.
  • Loan Interest Calculator
    Enter loan amount, annual rate, term, and compounding to see payment per period, total interest, total of payments, and effective annual rate.
  • Savings Growth with Regular Contributions Calculator
    Project the future value of your savings with an initial balance plus regular monthly, quarterly or annual contributions and compound interest.
  • Discount Factor (Present Value of $1) Table Creator
    Calculate your fixed monthly mortgage payment, total interest, and full amortization breakdown from loan amount, interest rate, and term.
  • Savings Account vs CD Calculator
    Calculate your Certificate of Deposit's value at maturity, total interest earned, and effective APY using compound interest. Free CD vs savings calculator.
  • Effective Annual Rate (EAR) Calculator
    Calculate the Effective Annual Rate (EAR) from a nominal rate and compounding frequency. See the true yearly interest cost or yield with EAR = (1 + i/n)^n − 1.
  • APR Calculator (Loan with Fees)
    Estimate a loan's APR by folding upfront fees and total interest into one annual percentage rate. Free, fast, simplified add-on APR calculator.
  • Implied Interest Rate Calculator
    Find the implied compound interest rate from a start value, end value, and number of periods using r = (A/P)^(1/n) − 1. Free and instant.
  • Annual Percentage Yield (APY) Calculator
    Calculate APY (Annual Percentage Yield) from a nominal rate and compounding frequency. See your true effective annual return with the formula APY = (1 + r/n)^n − 1.
  • Recurring Savings Calculator with Tax on Each Compounding
    Japan-style recurring deposit calculator that withholds tax (default 20.315%) on interest at every compounding period. Get a full schedule and maturity total.
  • Future Value Calculator with Contributions
    Calculate the future value of an investment with an initial principal plus regular monthly, quarterly or annual contributions and compound interest.
  • Present & Future Value Algebra Calculator
    Solve for present value or future value using FV = PV(1+r)ⁿ. Enter amount, rate per period, and number of periods to get instant results.
  • Solve Compound Interest for Rate or Time
    Solve the compound interest formula for the unknown interest rate or time. Enter principal, future amount and compounding frequency to find r or t.
  • Effective Annual Rate (APY) Calculator
    Convert a nominal annual interest rate into the effective annual rate (APY) using the compounding formula APY = (1 + r/n)^n − 1.
  • Continuous Compound Interest Calculator
    Calculate continuous compound interest with the formula A = Pe^(rt). Find the future value and total interest from principal, rate, and time instantly.

Frequently asked questions

What is the difference between simple and compound interest, and can I calculate both here?

Simple interest is applied only to the original principal; compound interest grows on accumulated interest too, making balances expand faster over time. Both are covered — the Simple Interest Calculator handles straightforward scenarios, while the Compound Interest and Reverse Compound Interest calculators model long-term growth.

How accurate are these interest calculators?

All tools apply standard, well-established interest formulas. Results are accurate estimates for financial planning. These calculators are not financial advice — actual rates and fees vary by lender and product. Consult a qualified financial professional before making significant borrowing or investment decisions.

Are the calculators free?

Yes. Every interest calculator on this page is free with no account needed. Enter your principal, rate, and time period — results appear instantly on any phone, tablet, or computer.

Do you store my financial inputs?

No. All calculations happen locally in your browser. Your principal amounts, interest rates, and personal finance data are never transmitted to or stored on our servers.

Which interest calculators do people use most?

The default list ranks tools by real-world usage. The Compound Interest Calculator and Loan Interest Calculator consistently appear near the top. Use the Trending tab to see which tools are gaining the most traction right now.