Investing & Personal Finance calculators

Which investing calculator should you use?

The right tool depends on what you are trying to understand. If you want to see how your money grows over time, the Compound Interest Calculator is the single most important calculator here — it shows you the long-term effect of rate and time on any starting amount. For recurring monthly investments, the SIP (Systematic Investment Plan) Calculator and Lump Sum Investment Calculator show how regular or one-time contributions compound over different time horizons.

To evaluate past performance, use the Investment Return Calculator or CAGR Calculator — CAGR (Compound Annual Growth Rate) is the standard way to compare returns across different time periods. For income-focused investors, Dividend Calculator shows annual and monthly income from dividend-paying stocks. The Retirement Calculator and Net Worth Calculator help with long-term financial planning.

The fundamentals of investing every beginner should know

Compound interest: the most powerful force in investing

Future value = Principal × (1 + rate)^years. At 8% annual return, $10,000 becomes $21,589 after 10 years and $46,610 after 20 years — not because of deposits but because earnings compound on previous earnings. Starting 10 years earlier roughly doubles your ending balance. This is why time in the market matters more than timing the market.

CAGR: the honest way to measure returns

Average annual return can be misleading. If an investment gains 50% in year one and loses 33% in year two, the average return is +8.5% — but you end up exactly where you started. CAGR = (End value ÷ Start value)^(1 ÷ years) − 1 gives the true annualised growth rate. The S&P 500's long-run CAGR is approximately 10% before inflation, or 7% in real terms.

Inflation: the silent return-killer

A 7% nominal investment return in a 3% inflation environment produces a 4% real return. Over 30 years, $100,000 growing at 7% nominally reaches $761,226 — but in today's purchasing power that may only be worth $314,000. The Inflation Calculator helps you understand what today's money will be worth in the future, or what a future amount is worth in today's terms.

Net worth: the only number that really matters

Net worth = Total assets − Total liabilities. Your income, savings rate, and investment returns are all inputs; net worth is the output. Track it quarterly. According to the Federal Reserve's Survey of Consumer Finances, the median US household net worth is approximately $192,700 — but the mean is $1.06M, heavily skewed by ultra-high-net-worth individuals.

Common investing mistakes to avoid

• Focusing on nominal returns instead of real (inflation-adjusted) returns. A savings account at 5% interest in a 4% inflation environment is barely growing your wealth in real terms.
• Underestimating fees. A 1% annual management fee sounds small but reduces a $100,000 portfolio's 30-year ending value by approximately $80,000 at 7% gross return — roughly 20% of total wealth.
• Stopping contributions during market downturns. Recessions are when compound interest does its best work — prices are low and each contribution buys more shares. Continuing SIP through downturns is mathematically superior to pausing.
• Confusing CAGR with average annual return. As shown above, these can differ dramatically in volatile markets. CAGR is the correct measure of actual wealth accumulation.
• Not accounting for taxes on investment returns. Capital gains, dividend income, and withdrawal taxes can meaningfully reduce your actual after-tax return. Run scenarios with the Capital Gains Tax Calculator before selling investments.

Frequently asked questions