How to Calculate Investment Returns

Calculating investment returns correctly is essential for comparing different investment options, evaluating performance, and making informed financial decisions. Many investors confuse total return with annualised return, which leads to poor comparisons between investments held for different periods. This guide breaks down the three main return metrics — ROI, CAGR, and annualised return — with clear examples.

Return on Investment (ROI) – the simplest measure

ROI measures the total percentage gain or loss from an investment, regardless of how long you held it.

ROI = [(Final Value – Initial Investment) / Initial Investment] × 100

Example: You invested $100,000 in stocks. After 3 years, the portfolio is worth $160,000.

ROI = [(1,60,000 – 1,00,000) / 1,00,000] × 100 = 60%

ROI is useful for a quick comparison but problematic when comparing investments held for different durations. A 60% ROI over 3 years is very different from a 60% ROI over 10 years.

CAGR – the most important metric for comparing investments

CAGR (Compound Annual Growth Rate) converts any ROI into an annualised rate that accounts for compounding. It is the standard metric for comparing mutual funds, stocks, and other market investments.

CAGR = [(Final Value / Initial Value)^(1/Years)] – 1

Expressed as a percentage: multiply the result by 100.

Example: $100,000 grows to $160,000 over 3 years.

CAGR = [(1,60,000 / 1,00,000)^(1/3)] – 1 = (1.6)^0.333 – 1 = 1.1696 – 1 = 0.1696 = 16.96% per year

This is far more useful than the raw 60% ROI when comparing against a fixed deposit yielding 7% annually.

Why CAGR can be misleading

CAGR shows a smooth annual rate, which hides volatility. An investment that doubled then halved has a CAGR of 0%, but the investor experienced significant stress along the way. CAGR is best used alongside a maximum drawdown measure to understand both return and risk.

Absolute return vs CAGR – when to use each

• Use absolute return (ROI) for investments held under 1 year, or when you simply want to know the total profit/loss
• Use CAGR for investments held over 1 year, or when comparing multiple investments across different time periods
• Use XIRR for monthly investment investments or any investment with multiple irregular cash flows — XIRR is the internal rate of return that accounts for the timing of each transaction

Real return – accounting for inflation

Nominal return ignores the eroding effect of inflation. Real return shows your actual purchasing power gain.

Real Return ≈ Nominal Return – Inflation Rate

More precisely: Real Return = [(1 + Nominal Return) / (1 + Inflation Rate)] – 1

If your investment returns 12% annually and inflation is 6%: Real Return = [(1.12/1.06)] – 1 = 5.66% per year. Your actual purchasing power grew by only 5.66%, not 12%.

Comparing fixed deposit vs mutual fund returns

Fixed Deposit: $100,000 at 7% for 5 years (annually compounding)

Final value = 1,00,000 × (1.07)^5 = $140,255. CAGR = 7%.

Equity Mutual Fund: $100,000 grows to $220,000 over 5 years

CAGR = [(2,20,000/1,00,000)^(1/5)] – 1 = (2.2)^0.2 – 1 = 1.1707 – 1 = 17.07% per year

The mutual fund returned 17.07% CAGR vs FD's 7% CAGR — but the mutual fund carried equity risk, while the FD was guaranteed. Risk-adjusted comparison is essential.

Tax impact on investment returns

The real net return after tax is often lower than the reported return. Key considerations:

• Equity capital gains tax (Long Term Capital Gains): Gains above $100,000 after 1 year taxed at 10%
• Equity STCG (Short Term Capital Gains): Gains within 1 year taxed at 15%
• Fixed Deposit interest: Taxed as income at your applicable slab rate (up to 30%)
• Debt Mutual Funds: Taxed as income at your slab rate

Post-tax CAGR is the most honest comparison metric for different investment types.

Frequently asked questions about investment returns

What is ROI and how do you calculate it? ROI = [(Final Value – Initial Investment) / Initial Investment] × 100. It measures total percentage gain regardless of time period.

What is CAGR? CAGR shows the annual rate at which an investment grew, assuming compounding. It is the most useful metric for comparing multi-year investments.

What is a good return on investment? This depends on the asset class. global equities have historically returned 12–15% CAGR over long periods. Fixed deposits offer 6–7%. Benchmark against inflation (5–6%) to assess real returns.

Why how you measure returns matters

The same investment can look very different depending on which return metric you use. An investment that returned 60% sounds excellent — until you learn it took 10 years (6% CAGR, which barely beats inflation). Choosing the right return metric allows you to compare investments with different time horizons, sizes, and cash flow patterns on equal terms.

ROI — Return on Investment

ROI is the simplest measure of investment performance. It shows the total percentage gain or loss regardless of time period.

ROI = [(Final Value – Initial Investment) ÷ Initial Investment] × 100

Examples:

• Bought a plot for $1,500,000, sold for $2,400,000: ROI = [(24 – 15) ÷ 15] × 100 = 60%
• Invested $80,000 in stocks, current value $68,000: ROI = [(68,000 – 80,000) ÷ 80,000] × 100 = –15%

ROI is useful for quick comparison but misleading across different time periods. A 60% ROI over 3 years is excellent. A 60% ROI over 15 years is poor (just 3.2% CAGR).

CAGR — Compound Annual Growth Rate

CAGR converts any investment's total return into an equivalent annualised rate, making different-length investments directly comparable.

CAGR = [(Final Value ÷ Initial Value)^(1 ÷ Years)] – 1

Expressed as percentage: multiply by 100.

Examples:

• $100,000 → $161,051 in 6 years: CAGR = (1.61051)^(1/6) – 1 = 1.08 – 1 = 8% CAGR
• $200,000 → $500,000 in 10 years: CAGR = (2.5)^(0.1) – 1 = 1.096 – 1 = 9.6% CAGR
• $500,000 → $1,800,000 in 12 years: CAGR = (3.6)^(1/12) – 1 = 1.115 – 1 = 11.5% CAGR

Real return — adjusting for inflation

Nominal return ignores the corrosive effect of inflation. A 10% annual return when inflation is 7% provides only 2.8% real purchasing power gain.

Real Return = [(1 + Nominal Return) ÷ (1 + Inflation Rate)] – 1

At 10% nominal, 6% inflation: Real return = (1.10 ÷ 1.06) – 1 = 1.0377 – 1 = 3.77%

This is why returns below inflation (negative real returns) mean your money is actually losing purchasing power even though the account balance is growing in nominal terms.

XIRR — for monthly investment and irregular cash flows

CAGR works for lump-sum investments with one entry and one exit. When cash flows occur at different times — as in a monthly investment plan — XIRR (Extended Internal Rate of Return) is the correct metric. XIRR calculates the annualised return that makes the net present value of all cash flows equal to zero. Most mutual fund platforms show XIRR for monthly investment investments. It accounts for the fact that earlier monthly investment instalments have been invested for longer and compounded more.

Comparing investment options

• Bank FD at 7.25%: Nominal CAGR = 7.25%. After tax at 30% slab: 5.075%. Real return at 6% inflation: approximately –0.88% (negative in real terms)
• government savings account at 7.1%: Fully tax-free. Real return at 6% inflation: approximately 1.04%. Better than taxable FD despite slightly lower rate.
• Equity mutual fund monthly investment — historical 15-year CAGR: 12–14% for diversified equity. After capital gains tax tax (10% above $100,000 gains): ~10.5–12.5%. Real return at 6% inflation: 4.2–6.1%.