Project portfolio growth with an initial investment, monthly contributions, and annual rate of return. Toggle inflation-adjusted results.
Investment Details
Projected Results
Final Portfolio Value
$343,778
The Investment Return Calculator projects how a brokerage portfolio grows over time, combining an initial lump-sum investment with regular monthly contributions and a compounding annual return. It's built for long-term planning — retirement, a house down payment, or general wealth building outside of tax-advantaged accounts.
Toggle 'inflation-adjusted' to see your results in today's purchasing power rather than future dollars. A portfolio that grows to $500,000 in 20 years feels very different once you account for inflation eating into what that money can actually buy — this calculator shows both the nominal and real picture side by side.
FV = PV(1+r)^n + PMT × [((1+r)^n − 1) / r]Future value combines growth on your initial investment with growth on a stream of monthly contributions, both compounding monthly. For the inflation-adjusted view, the same formula is run using a real rate of return (nominal rate minus inflation).
Example 1: $10,000 start, $500/month for 20 years at 8%
Initial investment of $10,000 plus $500/month for 20 years (240 months) at an 8% nominal annual return.
Final portfolio ≈ $323,000 — about $130,000 contributed and $193,000 from investment growth (roughly a 2.5× growth multiple).
Example 2: Same scenario, inflation-adjusted at 3%
Same $10,000 + $500/month for 20 years, but using a real return of 8% − 3% = 5% to reflect today's purchasing power.
Inflation-adjusted value ≈ $209,000 — roughly $114,000 less than the nominal figure, showing why real returns matter for long-term goals.
Example 3: The Rule of 72 in action
A $50,000 investment with no further contributions, growing at 8% per year, with no withdrawals.
Using the Rule of 72 (72 ÷ 8 = 9), the investment roughly doubles to $100,000 in about 9 years and doubles again to $200,000 by year 18.
Methodology
FV = PV×(1+r)^n + PMT×[(1+r)^n−1]/r (monthly compounding). Real return ≈ nominal rate − inflation rate (Fisher approximation).
The S&P 500 has returned approximately 10% annually before inflation over the past century, or about 7% after inflation. Individual stocks, bonds, and international equities vary. A diversified 60/40 portfolio has historically returned ~7–8% nominal.
Divide 72 by your annual return rate to estimate how many years it takes to double your money. At 8% per year, money doubles in roughly 9 years (72 ÷ 8). At 6%, it takes 12 years.
Returns compound when gains are reinvested, earning future returns on top of prior gains. A $10,000 investment at 8% grows to $10,800 after year one. In year two, you earn 8% on $10,800 (not just $10,000), giving $11,664 — the extra $64 is compounding at work.
Disclaimer: Calculations are for informational purposes only and do not constitute professional financial advice. Please consult with a certified professional before making financial decisions.