Investment Calculator

Calculate • Compound • Grow Your Wealth

Investment Details

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Initial Investment

Monthly Contribution

Expected Return (%)

Time Horizon (years)

Inflation Rate (%)

Employer Match (%)

Calculate Your Investment Growth

Enter your details and see how compound interest can grow your wealth over time

What You'll Get

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Final Balance

Your exact portfolio value after compound growth

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Growth Chart

Visual year-by-year wealth trajectory

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Principal vs Interest

See how much you contributed vs how much it grew

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Inflation-Adjusted Value

Real purchasing power of your future balance

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Instant

Results in milliseconds

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100% Free

No signup, no credit check, unlimited calculations

📋 How It Works

Enter Your Investment Details

Initial amount, monthly contribution, expected return, and time horizon

See Compound Growth

Instant breakdown of total interest earned and final balance

Compare Scenarios

Adjust rate or contributions to find your optimal strategy

How to Calculate Investment Returns

Investment growth is calculated using the future value formula, which accounts for your initial lump sum, regular contributions, expected rate of return, and time horizon. The power of this formula comes from compounding — each year's gains become part of the base that earns returns the next year.

Future Value Formula

FV = PV × (1 + r)ⁿ + PMT × [(1 + r)ⁿ – 1] / r

FV = future value (final portfolio balance)

PV = present value (initial investment)

PMT = monthly contribution

r = monthly return rate (annual rate ÷ 12)

n = total months invested

Worked Example

Initial investment: $5,000 | Monthly contribution: $500 | Annual return: 8% | Time: 30 years

Monthly rate r = 8% ÷ 12 = 0.667%. After 360 months: FV = 5,000 × (1.00667)³⁶⁰ + 500 × [(1.00667)³⁶⁰ – 1] / 0.00667 = $735,872. You invested $185,000 total; compounding turned it into $735,872 — a gain of $550,872.

Investment Calculator — Frequently Asked Questions

What is the average stock market return?

The S&P 500 has returned an average of approximately 10% per year (nominal) since 1926, or about 7% after accounting for inflation. However, returns vary significantly year to year — from -38% in 2008 to +32% in 2013. Financial planners commonly use 6%–8% as a conservative long-term return assumption for planning purposes.

How much should I invest per month to become a millionaire?

The amount depends on your time horizon and expected return. Assuming a 8% annual return: to reach $1,000,000 in 30 years, you need to invest approximately $671/month. In 25 years, $1,052/month. In 20 years, $1,698/month. In 40 years, just $286/month. Starting earlier dramatically reduces the monthly contribution needed.

What is FIRE (Financial Independence, Retire Early)?

FIRE is a movement and financial strategy focused on aggressive saving and investing to achieve financial independence decades before traditional retirement age. The core principle is the 4% rule: if your investment portfolio equals 25× your annual expenses, you can withdraw 4% per year indefinitely. Someone spending $50,000/year needs a $1,250,000 portfolio to be financially independent.

Should I pay off debt or invest first?

The general rule: if your debt interest rate is higher than your expected investment return, pay off debt first. High-interest debt (credit cards at 20%+) should always be paid off before investing. Low-interest debt (mortgage at 6–7%) is a tougher call — many financial advisors suggest investing in a 401(k) up to the employer match first (free 50–100% return), then paying down debt, then investing additional funds.

What is dollar cost averaging?

Dollar cost averaging (DCA) means investing a fixed amount at regular intervals regardless of market price — for example, $500/month into an index fund every month. When prices are high, you buy fewer shares. When prices are low, you buy more. Over time, this smooths out the impact of volatility and removes the pressure to time the market perfectly. Most financial experts recommend DCA for long-term investors.

How does inflation affect investment returns?

Inflation erodes purchasing power over time. A 10% nominal return with 3% inflation equals a 7% real return. This matters enormously over decades: $100,000 growing at 10% nominal becomes $1,745,000 in 30 years, but its purchasing power in today's dollars is only $720,000 (adjusted for 3% inflation). Always think in terms of real (inflation-adjusted) returns when planning for retirement.

What is the difference between stocks and index funds?

Individual stocks represent ownership in a single company, giving higher potential returns but also higher risk. Index funds (like those tracking the S&P 500) hold hundreds or thousands of stocks simultaneously, providing instant diversification. Research consistently shows that over 10–20 year periods, low-cost index funds outperform the majority of actively managed funds, largely because of lower fees. For most investors, index funds are the recommended starting point.

What is a good investment return per year?

A "good" return depends on the asset class and time period. For a diversified stock portfolio: 7–10% annually is historically normal. For bonds: 3–5%. For real estate: 8–12% including appreciation and rental income. For high-yield savings accounts in 2024–2025: 4.5–5.5%. Any strategy promising consistently above 12% annual returns should be approached with extreme caution, as higher returns always come with higher risk.