Compound Interest Calculator

• Compound growth means the last decade of your horizon does the heaviest lifting — start early.
• A 1% higher return assumption can double the projected value over 30+ years — be conservative.
• Inflation-adjusted (real) return is what actually determines your future purchasing power.

1. 1Enter the amount you plan to invest (one-time or monthly).
2. 2Set the expected annual return and investment horizon.
3. 3Adjust contributions, step-up, and inflation assumptions.
4. 4Review projected value, gains, and year-by-year growth.
5. 5Save or share the projection for your financial plan.

• DIY investors planning long-term growth
• Anyone starting a SIP or 401(k)/IRA contribution
• Retirees estimating a safe withdrawal rate
• Advisors modelling portfolio projections

• When starting a new SIP, 401(k) or IRA
• During annual portfolio reviews
• Before rebalancing or increasing contributions
• When planning a retirement date

• Expected annual return and volatility
• Contribution amount and frequency
• Time horizon and start age
• Inflation, taxes and fees
• Employer match (for 401(k))

Illustrative examples using U.S. market averages. Enter your own numbers above for a personalized figure.

• Assuming a fixed rate of return every year.
• Ignoring inflation when projecting future value.
• Not accounting for taxes on gains or distributions.

• Increase your contribution rate with each raise — even 1% compounds meaningfully.
• Stress-test your plan with a lower return assumption to see the downside.
• Always max the employer match before adding to a taxable account.

• Long-horizon projections with realistic inflation and fee drag.
• Compare lump-sum vs SIP vs step-up strategies instantly.
• Employer match, tax bracket and Roth vs Traditional scenarios built in.
• Year-by-year growth table you can export or share.

• Returns are assumptions, not guarantees — actual results will vary.
• Ignores sequence-of-returns risk unless you model it explicitly.
• Tax treatment depends on your jurisdiction and account type.
• Not personalized investment advice — consult a fiduciary before acting.

CAGR

Compound Annual Growth Rate — the smoothed yearly return that would take you from your starting value to your ending value over the period.

Real vs nominal return

Nominal return ignores inflation; real return subtracts it. Only real return reflects future purchasing power.

Dollar-cost averaging

Investing a fixed amount on a regular schedule. Reduces timing risk and smooths out entry prices over long horizons.

Expense ratio

The annual fee a fund charges as a % of assets. Even 0.5% higher fees can cost tens of thousands over 30 years.

Safe withdrawal rate

The % of a retirement portfolio you can withdraw yearly without running out — the classic 4% rule is a starting point, not a guarantee.

• Confirm the account type (Roth, Traditional, taxable) matches your tax strategy.
• Capture the full employer match before contributing anywhere else.
• Stress-test the plan at a 2% lower return and higher inflation before relying on it.
• Set an automatic contribution and an annual step-up on your raise date.

The formulas, rates and definitions used by this calculator are aligned with the following official sources:

• U.S. Securities and Exchange Commission — Investor.gov — Official compound-interest and growth conventions.
• FINRA — Fund Analyzer & Investor Education — Expense-ratio, fee-drag and fund-comparison methodology.
• U.S. Department of the Treasury — Interest Rate Data — Benchmark Treasury yields for risk-free comparison.
• IRS — Investment Income and Expenses (Pub. 550) — Capital gains, dividends and cost-basis rules.

We use only primary sources — regulators, standards bodies and scheme operators. See our full sourcing policy for details. Sources & References Policy · Calculator Methodology · How We Verify Formulas

We continuously review and improve our calculators to keep formulas, assumptions and references accurate.

In-depth investment guides, worked examples, and expert explainers.

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