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Compound Interest Calculator
Project your long-term investment wealth, simulate recurring deposits, and visualize the power of compounding growth.
Investment Parameters
$
$
%
Yrs
Projected Wealth Summary
Future Investment Balance
$96,734.21
After 15 Years of Compounding
Total Principal Invested
$55,000.00
Total Interest Earned
$41,734.21
Principal: 57%
Interest: 43%
Tip: Reinvesting dividends and starting just 5 years earlier can double your total compound returns due to exponential curvature.
Year-by-Year Growth Schedule
| Year | Deposits (Year) | Total Contributed | Interest Earned (Year) | Total Interest | Ending Balance |
|---|
What is Compound Interest and How Does It Work?
Compound interest is the addition of interest to the principal sum of a loan or deposit, essentially earning interest on interest. Over extended multi-year periods, compounding transforms modest recurring contributions into significant wealth portfolios through non-linear geometric accumulation.
Key Capabilities & Features
- Flexible Contribution Frequencies: Simulate monthly dollar-cost averaging (DCA) or annual lump-sum deposits.
- Multiple Compounding Intervals: Calculate accurate returns for monthly, quarterly, semi-annual, annual, and daily schedules.
- Detailed Annual Amortization Table: Inspect exact interest and ending balances for every individual year.
- 1-Click CSV Export: Download full balance trajectories for budgeting in Excel, Google Sheets, or Numbers.
Step-by-Step How It Works
- Enter your starting investment (principal amount) and any recurring monthly or annual deposits.
- Set your expected annual return percentage based on historical stock market indices, bonds, or savings yields.
- Specify your investment horizon in years to project total wealth accumulation.
- Analyze the breakdown between money you put in (principal) and money earned through interest.
Frequently Asked Questions
The Rule of 72 is a quick mental math shortcut to estimate how many years it will take for your money to double at a given annual interest rate. Simply divide 72 by your interest rate (e.g., at 8% return,
72 / 8 = 9 years to double).
APR (Annual Percentage Rate) reflects the nominal stated interest rate without accounting for intra-year compounding. APY (Annual Percentage Yield) calculates the true effective rate you actually earn after compounding effects are included.
This calculator shows nominal nominal gross returns. To approximate inflation-adjusted "real purchasing power", subtract the typical 2-3% annual inflation rate from your nominal return rate (e.g., enter 6% if nominal return is 8-9%).