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Compound Interest Calculator: Grow Your Wealth

Written by Calcida Team
Reviewed for accuracy and clarity
Last updated: April 2026

See how compound interest can grow your money over time. Compare daily, monthly, and annual compounding frequencies.

This calculator is useful for investors and savers projecting growth from compounding. You will typically enter Starting balance, Contribution, Return rate, Time horizon.

The result represents projected balance and total interest earned. If you are browsing similar tools, start with Investment Calculators or view the full calculators directory.

Also useful: Savings Calculator: Reach Your Financial Goals, Investment Return Calculator (ROI).

Future Value

$300,851

Total Principal

$130,000

Total Interest

$170,851

Wealth Growth Over Time

See your investment growth potential

Model how compound interest builds wealth over decades.

How This Calculator Works

Compound interest is the interest on a loan or deposit calculated based on both the initial principal and the accumulated interest from previous periods. It is often described as "interest on interest."

The Compound Interest Formula:

A = P(1 + r/n)^nt

  • A = the future value of the investment/loan, including interest
  • P = the principal investment amount
  • r = the annual interest rate (decimal)
  • n = the number of times that interest is compounded per unit t
  • t = the time the money is invested or borrowed for

Formula

FV = P(1 + r)^t + PMT × [ ((1 + r)^t − 1) / r ]
Where:
  • P = principal (starting amount)
  • PMT = periodic contribution
  • r = periodic return rate
  • t = number of periods

Example Calculation

Starting amount$10,000
Monthly contribution$300
Return rate7%/year
Time20 years
Typical outcome
Interest can exceed total contributions over long horizons

The Power of Compound Interest

Compound interest is one of the most important concepts in finance. It's the reason why starting to save early can lead to massive wealth over time. Albert Einstein reportedly called it the "eighth wonder of the world."

How Compounding Frequency Affects Growth

The more frequently interest is compounded, the faster your money grows. For example, interest compounded daily will result in a higher final balance than interest compounded annually at the same rate.

  • Daily Compounding: 365 times per year
  • Monthly Compounding: 12 times per year
  • Quarterly Compounding: 4 times per year
  • Annual Compounding: Once per year

Compound Interest vs. Simple Interest

Simple interest is only calculated on the principal amount. Compound interest, however, includes the interest earned in previous periods. Over long periods, the difference becomes staggering.

Why Time is Your Best Friend

The earlier you start investing, the more time compound interest has to work its magic. Even small amounts can grow significantly over decades.

Frequently Asked Questions

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