Fill in your details on the left and click Calculate Growth to see how your money grows over time.
With compound growth, your returns also earn returns. Every time interest is added, the new total becomes your base for the next period. This is called "interest on interest" and it is the reason money can grow so fast over long periods.
For example, if you invest $5,000 at 8% per year, by year 10 you have about $10,795 — more than double — without adding a single extra dollar.
Divide 72 by the annual rate to estimate how many years your money takes to double.
| Annual Rate | Years to Double | ×5 in Years |
|---|---|---|
| 3% | 24 years | 54 years |
| 5% | 14.4 years | 33 years |
| 7% | 10.3 years | 24 years |
| 8% | 9 years | 21 years |
| 10% | 7.2 years | 17 years |
| 12% | 6 years | 14 years |
| 15% | 4.8 years | 11 years |
CAGR (Compound Annual Growth Rate) is the steady yearly rate that takes you from a starting value to an ending value over a number of years. It smooths out ups and downs. Investors use it to compare different assets or time periods.
Formula: CAGR = (End ÷ Start)1/Years − 1
Simple growth just adds the same fixed dollar amount each year. Compound growth adds a percentage, so the dollar amount grows every year. A $10,000 investment growing at 8% simple earns $800 every year. At 8% compound, it earns $800 in year 1, $864 in year 2, $933 in year 3, and so on.
The more often interest is compounded, the higher your final balance — but the difference is smaller than many people expect. The biggest gains come from rate and time, not frequency.
| Frequency | $10k @ 10% / 10 yrs | Difference |
|---|---|---|
| Annual | $25,937 | Baseline |
| Quarterly | $26,851 | +$914 |
| Monthly | $27,070 | +$1,133 |
| Daily | $27,179 | +$1,242 |
| Continuous | $27,183 | +$1,246 |
Monthly compounding assumed. Shows how a single lump-sum investment grows over time.
| Annual Rate | 5 Years | 10 Years | 15 Years | 20 Years | 25 Years | 30 Years |
|---|
Based on $10,000 principal. Monthly compounding. Formula: A = P(1+r/12)12t.
How often interest is applied affects your final balance. Compare frequencies side by side.
| Compounding | Periods/Year | Final Balance | Interest Earned | Effective Annual Rate | Extra vs Annual |
|---|
Principal: $10,000. Rate: 8%. Period: 20 years. Annual compounding used as baseline.
Compare the Rule of 72 estimate with the exact doubling time at annual compounding.
| Annual Rate | Rule of 72 Estimate | Exact Years | Error | ×3 in Years | ×5 in Years | ×10 in Years |
|---|
Exact doubling = ln(2)/ln(1+r). Annual compounding. Rule of 72 is most accurate between 5–15%.
Starting with $10,000, adding regular monthly contributions at 8% per year (monthly compounding) over 20 years.
| Monthly Add | Total Contributed | Interest Earned | Final Balance | Multiplier |
|---|
Principal: $10,000. Rate: 8%. Time: 20 years. Monthly compounding. Contributions made at start of each month.
Reference rates for savings, bonds, and stock markets around the world. For context only — actual rates vary and change over time.
| Country / Market | Central Bank Rate | Savings Rate (Approx.) | 10-yr Bond Yield | Stock Market (Hist. Avg.) | Inflation (Recent) |
|---|---|---|---|---|---|
| 🇺🇸 USA | 4.25–4.50% | 4–5% | ~4.3% | ~10% (S&P 500) | ~3–4% |
| 🇬🇧 UK | 5.25% | 4–5% | ~4.1% | ~7% (FTSE 100) | ~4–5% |
| 🇪🇺 Eurozone | 4.00% | 3–4% | ~2.5% | ~8% (STOXX 600) | ~3–4% |
| 🇯🇵 Japan | 0.10% | 0.1–0.3% | ~0.9% | ~7% (Nikkei) | ~2–3% |
| 🇨🇳 China | 3.45% | 1.5–2% | ~2.3% | ~5–6% | ~0–1% |
| 🇮🇳 India | 6.50% | 6–7% | ~7.1% | ~12% (SENSEX) | ~5% |
| 🇦🇺 Australia | 4.35% | 4–5% | ~4.3% | ~8–9% (ASX) | ~3–4% |
| 🇨🇦 Canada | 5.00% | 4–5% | ~3.7% | ~7–8% (TSX) | ~3% |
| 🇧🇷 Brazil | 10.50% | 9–11% | ~11% | ~10–12% | ~5% |
| 🇿🇦 South Africa | 8.25% | 7–8% | ~10% | ~9% | ~5–6% |
Rates shown are approximate and for reference only. Central bank rates and market returns change frequently. Always verify with current sources before making financial decisions.
How capital gains taxes reduce your final take-home value. Tax applied to gains only at end of period (deferred).
| Time Period | Gross Value | After 10% Tax | After 15% Tax | After 20% Tax | After 25% Tax | After 30% Tax |
|---|
Principal: $10,000. Rate: 8%. Monthly compounding. Tax applied once to total gains at end (lump-sum deferred tax model). Actual tax rules vary by country, account type, and holding period.