Compound scenario · Verified 2026-05-27
How long for $10,000 to double at S&P 500 average 10%?
Grows to $22,182 over 8 years. You contribute $10,000; the remaining $12,182 (55%) comes from compound growth.
Final balance
$22,182
You contributed
$10,000
From compounding
$12,182
Live calculator (pre-filled with this scenario)
Change any input to explore variations. Or open this exact scenario in the full calculator.
Year-by-year breakdown
| Year | Total contributed | Interest earned | Balance |
|---|---|---|---|
| 1 | $10,000 | $1,047 | $11,047 |
| 2 | $10,000 | $2,204 | $12,204 |
| 3 | $10,000 | $3,482 | $13,482 |
| 4 | $10,000 | $4,894 | $14,894 |
| 5 | $10,000 | $6,453 | $16,453 |
| 6 | $10,000 | $8,176 | $18,176 |
| 7 | $10,000 | $10,079 | $20,079 |
| 8 | $10,000 | $12,182 | $22,182 |
How this number was calculated
Standard compound interest formula with monthly compounding (n = 12):
Balance = P × (1 + r/n)^(n × t) + PMT × [((1 + r/n)^(n × t) − 1) / (r/n)] where: P = $10,000 (initial amount) PMT = $0 (monthly contribution) r = 0.1000 (annual rate as decimal) n = 12 (compounding periods per year) t = 8 (years) Final balance = $22,182
Same closed-form math used by Investor.gov (SEC) and 7 other major calculators we tested — all produce identical results to the cent.
Related scenarios
How long does it take $10,000 to double at 7%?
→ $21,549 (11 years at 7%)
How long for $100,000 to double at 8%?
→ $221,964 (10 years at 8%)
Try other scenarios
Snowballr's full compound investment calculator
Compare 3 scenarios side-by-side, run Monte Carlo with 1,000 probability paths, share by URL, embed on your site.
Open the calculator →Educational tool. Past performance does not predict future returns. Verified 2026-05-27. Math validated against Robert Shiller's S&P 500 historical dataset.