Compounding frequencies
Monthly compounding applies interest 12 times per year. Daily applies 365 times. More frequent compounding yields slightly more interest.
Finance calculators
Compound Interest Calculator
Calculate future value with compound interest over time.
Complete guide
How to use Compound Interest Calculator
Compound interest grows your principal by applying interest not only to the initial deposit but also to all previously earned interest. The formula is A = P(1 + r/n)^(nt), where P is principal, r is annual rate, n is compounding frequency, and t is years.
More frequent compounding (daily vs annually) produces slightly higher returns. The difference becomes significant over long time periods.
The power of time
Doubling the investment period has a much larger impact than doubling the interest rate. Starting early matters enormously.
Rule of 72
Divide 72 by the interest rate to estimate how many years it takes to double your investment. At 7%, money doubles in about 10.3 years.
Answers
Compound Interest Calculator FAQs
What is compound interest?
Interest calculated on both the initial principal and accumulated interest from previous periods.
How is compound interest different from simple interest?
Simple interest only applies to the principal. Compound interest also applies to previously earned interest, growing faster over time.
What is the best compounding frequency?
More frequent compounding yields more interest, but the difference between monthly and daily is small for typical investments.
What is a realistic return rate?
The S&P 500 has historically averaged around 7-10% annually before inflation. Savings accounts are much lower.
How do I use this to plan savings?
Enter your starting amount, expected interest rate, and how many years you plan to save to see the projected value.
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Calculation method and limitations
Formula or method
Future value = P x (1 + r / n)^(n x t), where P is principal, r is annual rate as a decimal, n is compounding periods per year, and t is years.
Worked example
A $10,000 principal at 7% annual interest compounded monthly for 10 years becomes approximately $20,096.61. Interest is approximately $10,096.61.
Assumptions and limitations
Assumes a constant nonnegative nominal rate, no additional deposits and no withdrawals. Taxes, investment fees and inflation are excluded; growth is not guaranteed.
Important: For educational planning only. Rates, tax rules, fees, and eligibility vary; confirm important decisions with a qualified professional.
Editorial note: Review the input definitions, units and assumptions before relying on results. For corrections, contact FormatNest with your inputs and expected result.