Missed Investment Calculator
Enter any past purchase and see what it would be worth today if you had invested it instead — powered by real compound interest math.
Every dollar spent is a dollar not compounding — at 10% annual return, $1,000 spent today costs you $17,000 over 30 years.
10×
$1,000 invested 25 years ago at 10% annual return is worth over $10,000 today
7%
Inflation-adjusted average real return of the S&P 500 — the conservative benchmark
$87k
What a $5,000 impulse purchase at age 25 costs in retirement wealth at age 65 (7%)
The real price of every purchase
What compound interest means for your spending decisions.
Compound interest is ruthlessly asymmetric
The first few years of compounding look modest. The last few years are explosive. A $1,000 investment at 10% grows by $100 in year 1, but by $1,746 in year 30 alone. This is why time in the market matters far more than timing the market — and why early spending is so much more expensive than it looks.
The latte factor is real — but it's not lattes
David Bach's 'latte factor' has been mocked, but the math is right for larger purchases. The $5 coffee matters little. The $1,200 holiday upgrade, the $3,000 car option, the $500/month subscriptions — these are where the real opportunity cost lives. This calculator makes those numbers concrete.
Use it forwards, not just backwards
Don't just calculate what past purchases cost you — use it before future ones. Enter the purchase amount and your years until retirement. That's the true price tag. A $10,000 car upgrade at age 30 costs $76,000 in retirement wealth at a 7% real return over 35 years.
How the Missed Investment Calculator Works
Formula
Future Value = Amount × (1 + Annual Return)^Years
Total Gain = Future Value − Original Amount
Multiplier = Future Value ÷ Original Amount
Monthly Cost = Total Gain ÷ (Years × 12)Enter the amount spent
Any past or future purchase — holiday, gadget, subscription, upgrade.
Enter years ago (or years ahead)
How many years since the purchase, or until retirement for forward planning.
Set annual return
10% for S&P 500 historical average. 7% for inflation-adjusted real return. 12% for aggressive assumptions.
Read the result
Current value, total gain missed, multiplier on original amount, and the monthly opportunity cost spread over the period.
This calculator uses basic compound interest (no dividends reinvestment or tax adjustments). For a more complete picture of real investment returns, use the Compound Interest Calculator which supports regular contributions.
Past returns don't guarantee future performance. The 10% S&P 500 average is a widely-used benchmark, not a promise. Use 5–7% for more conservative planning.
Frequently Asked Questions
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