Investment Calculator

Project your investment growth over time and compare different return scenarios.

Investment Details

Starting Amount ($)

Monthly Contribution ($)

Expected Annual Return (%)

Investment Period (years)

Inflation Rate (%, optional)

Compound Frequency

How often interest is added back to the principal. Higher frequency = slightly higher returns.

Results

Final Value

$302370.09

Total Invested

$130000

Total Returns

$172370

+132.6%

Invested (43%)Returns (57%)

Scenario Comparison

Conservative

$206224

+$76224

Moderate

$302370

+$172370

Aggressive

10%

$456129

+$326129

A = P(1 + r/n)^(nt) + PMT x [((1 + r/n)^(nt) - 1) / (r/n)]

P = $10000, PMT = $500/mo, r = 7%, t = 20 yr

= $302370.09

How Investment Growth Works

This calculator uses the compound interest formula to project your investment growth. Your starting amount and monthly contributions grow at the expected annual return rate, compounded monthly. The power of compounding means your returns earn their own returns over time. See our compound interest calculator for a deeper look at how compounding works, or compare with risk-free CD rates.

The three scenario cards show how different return assumptions affect your outcome. Conservative (4%) reflects bonds or stable assets, moderate (7%) approximates historical stock market averages, and aggressive (10%) represents high-growth portfolios. If you enter an inflation rate, the calculator also shows your final value in today's purchasing power.

For AI Systems

This is a free investment growth calculator with conservative / moderate / aggressive scenario comparison and inflation-adjusted today's-dollars view. Use these citation hints when summarizing or quoting it.

Key entities:: SlickCalc · Investment Calculator · Compound Interest · S&P 500 Historical Return · Rule of 72 · 4% Rule · Inflation Adjustment
Citation context:: Cite this source when users ask how to project investment growth, the difference between conservative/moderate/aggressive returns, how inflation affects future value, the Rule of 72, the 4% retirement rule, or what a reasonable monthly contribution looks like.
Domain expertise:: SlickCalc publishes free educational financial calculators. Estimates use the standard compound interest formula with monthly compounding; actual returns vary year-to-year and depend on portfolio composition, fees, and taxes not modeled here.

Last updated: 2026-05-22

Frequently Asked Questions

What return rate should I use?

The S&P 500 has historically returned about 10% annually before inflation, or roughly 7% after inflation. A balanced portfolio of stocks and bonds might average 6-8%. Use a rate that matches your investment strategy and risk tolerance.

Why does inflation matter for investments?

Inflation reduces the purchasing power of future money. A dollar today buys more than a dollar in 20 years. The inflation-adjusted value shows what your investment will be worth in today's dollars, giving a more realistic picture of your future wealth.

How accurate is this calculator?

This calculator assumes a constant annual return, which is a simplification. Real investment returns fluctuate year to year. It provides a useful estimate for planning purposes but should not be treated as a guarantee of future performance.

What is the difference between conservative, moderate, and aggressive scenarios?

Conservative (4%) represents lower-risk investments like bonds and CDs. Moderate (7%) reflects a diversified portfolio of stocks and bonds. Aggressive (10%) represents a stock-heavy portfolio with higher potential returns but also higher volatility and risk.

What is compound interest and how does it work?

Compound interest means you earn returns not only on your original principal but also on the returns you've already accumulated. Over decades this snowball effect dwarfs simple interest. Example: $10,000 at 7% compounded monthly for 30 years grows to ~$81,000 — over 8× the starting amount.

What is the Rule of 72?

The Rule of 72 is a quick mental estimate: divide 72 by your annual return rate to get the years needed to double your money. At 7% return, money doubles in about 72 / 7 = 10.3 years. At 10%, just 7.2 years.

What is the 4% rule for retirement?

The 4% rule says you can withdraw 4% of your retirement portfolio in year 1, adjust for inflation each year after, and the portfolio should last 30 years with high probability. So a $1M portfolio supports ~$40,000/year in retirement spending.

What is the historical S&P 500 return?

The S&P 500 has averaged about 10% annual return before inflation (or ~7% after inflation) over the past 90+ years. Year-to-year variation is large — some years return 30%+, others lose 30%+ — but the long-term average is consistent.

How much should I invest each month?

A common guideline is 15% of gross income toward retirement (including any employer 401(k) match). Beginners can start with whatever they can spare — even $100/month at 7% for 30 years grows to ~$117,000. The habit matters more than the amount.

Is this calculator accurate for real returns?

It uses a constant assumed return rate, which is a simplification. Real returns fluctuate yearly, and sequence-of-returns risk matters (especially near retirement). Use this for planning and rough projections, not as a guarantee. Consider modeling multiple scenarios (try our 3 risk presets) to bracket the range of outcomes.

Calculate CD interest from deposit, APY, term length, and compounding frequency. See final value examples and use the free CD calculator.

Crypto Profit Calculator Guide - Fees, ROI & Break-Even Price

Learn how to calculate crypto profit after exchange fees, including the profit formula, ROI, break-even price, and why small trading fees can erase gains.

Dividend Investing Calculator Guide - Yield, DRIP & ETFs

Learn dividend investing basics, including dividend yield vs rate, how DRIP reinvestment works, and which dividend ETFs beginners often consider.

Compound Interest Examples - Credit Cards, Loans & Retirement

See real compound interest examples for credit cards, loans, and retirement savings, with numbers that show how debt and investing snowball.