Back to Calculators

Compound Interest Calculator

See how your money grows over time with compound returns. Factor in monthly contributions, taxes, and inflation for accurate long-term projections.

Investment Parameters

Required Inputs

$
$

Optional Inputs

Mutual fund expense ratio, advisor fee, etc.

📊 Monte Carlo Simulation

Model market volatility to see range of possible outcomes

Results

Final Balance
$0
Total Contributions
$0
Total Interest
$0
After-Tax Balance
$0
Inflation Adjusted
$0
Effective Return
0%

💰 Inflation Impact Analysis Understanding Real Purchasing Power

Nominal Value (Future Dollars)
$0
What you'll see in your account
Real Value (Today's Dollars)
$0
Actual purchasing power
Purchasing Power Lost
$0
Impact of inflation
Real Return Rate
0%
Inflation-adjusted growth
💡 What This Means:

Inflation erodes purchasing power over time. While your account shows $0, that money will only buy what $0 buys today. This is why it's important to invest in assets that grow faster than inflation.

💸 Fee Impact Analysis The Hidden Cost of Investment Fees

Balance WITHOUT Fees
$0
If you paid 0% fees
Balance WITH Fees
$0
At 1% annual fee
Total Fees Lost
$0
Money that went to fees
Percentage Lost to Fees
0%
Of potential gains

Fee Impact: A seemingly small 1% annual fee can cost you 25-35% of your potential gains over 30 years due to compounding. Index funds (0.03%-0.20%) vs actively managed funds (0.5%-2.0%) can mean hundreds of thousands in lost wealth.

📊 Tax Impact Analysis Understanding Your After-Tax Returns

Pre-Tax Final Balance
$0
Total before taxes
Taxable Gains
$0
Interest earned (taxable)
Estimated Tax Owed
$0
At 15% tax rate
After-Tax Final Balance
$0
What you actually keep

Tax Treatment: Investment gains are taxed based on holding period. Long-term gains (>1 year) are taxed at 0%, 15%, or 20% based on income. Short-term gains (<1 year) are taxed as ordinary income at your marginal tax rate. This calculator uses the tax rate you specify above.

Year-by-Year Breakdown

Year Starting Balance Contributions Interest Earned Tax Owed Ending Balance (After Tax)

How Compound Interest Works

Compound interest is the interest calculated on the initial principal and also on the accumulated interest of previous periods. This "interest on interest" effect can significantly increase your investment returns over time.

The Compound Interest Formula

A = P(1 + r/n)^(nt)
Where:
• A = Final amount
• P = Principal (initial investment)
• r = Annual interest rate (decimal)
• n = Number of times interest compounds per year
• t = Number of years

Tips for Maximizing Compound Interest