Compound Interest Calculator

See how your investments grow with compound interest. Add monthly contributions and choose your compounding frequency.

About Compound Interest Calculator

This free compound interest calculator shows how your money can grow over time. Enter your initial investment, recurring monthly contributions, expected annual return, and choose how frequently interest compounds — daily, monthly, quarterly, or annually. The results show your final balance, total contributions, total interest earned, and a year-by-year breakdown of growth.

See Your Money Grow

Watch how compound interest accelerates your wealth over time with clear visual results.

Multiple Frequencies

Compare how daily, monthly, quarterly, and annual compounding affect your final balance.

Regular Contributions

Include ongoing monthly investments to see the full picture of a disciplined savings plan.

Year-by-Year Table

Expand the yearly breakdown to see your balance, contributions, and interest earned each year.

📋 Common Use Cases

Retirement Planning

Project your nest egg at retirement age based on current savings, monthly contributions, and expected returns. Adjust variables to see when you can comfortably retire.

Goal-Based Saving

Calculate how much to save monthly to reach a specific target — college fund, house down payment, or emergency fund — by your desired deadline.

Compare Investment Strategies

Test different asset allocations and return rates. See how a 1-2% difference in annual returns compounds into significant differences over decades.

Windfall Planning

Decide between lump-sum investing vs dollar-cost averaging an inheritance or bonus. Let the numbers show which approach maximizes your long-term returns.

🪜 How to Use This Tool

  1. Enter your starting point
    Input your current savings balance, expected monthly contribution, and investment time horizon in years.
  2. Set your expected return rate
    Choose a realistic annual return based on your investment strategy. Conservative portfolios might use 4-6%, aggressive ones 8-10%.
  3. Review growth projections
    See year-by-year growth, total contributions vs investment earnings, and your final balance. Charts visualize how compound interest accelerates over time.
  4. Test what-if scenarios
    Try different contribution amounts, return rates, or time horizons. Small changes early in your career compound into massive differences at retirement.

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Frequently Asked Questions

Are these calculators really free?▼
Yes. All calculators on iluv.tools are completely free. No signup, no account, no credit card required. Every calculation runs instantly in your browser.
Is my data sent anywhere?▼
Absolutely not. All calculators are pure client-side JavaScript. Your numbers, dates, and inputs never leave your browser. No server processing, no tracking.
How accurate are these calculators?▼
Calculators use standard mathematical formulas with double-precision floating point. Results match industry-standard financial and scientific calculations.
Can I use calculators on mobile?▼
Yes. All calculators work on mobile browsers (iOS Safari, Android Chrome) with responsive layouts.