What a lump-sum investment grows into
This investment calculator projects how a single lump sum grows with compound interest over time, with no ongoing contributions. Enter the amount you are investing today, an expected annual return, and a time frame, and it shows the future value, the total returns earned, the growth multiple, and a year-by-year chart. Switch to find-principal mode to work backward from a target to the amount you need to invest today.
How to use it
- Enter your initial investment amount.
- Set the expected annual return and how often it compounds.
- Set the time period in years.
The result updates as you type.
How the future value is calculated
A lump sum compounds on itself every period:
Because there are no further contributions, the whole balance is one starting sum left to grow. That is what separates this from the compound interest calculator, where you also add money regularly, and the SIP calculator, which is built for a recurring contribution.
How long it takes to double your money
A useful mental shortcut is the Rule of 72: divide 72 by your annual return to estimate the doubling time. At 8%, your money roughly doubles every 9 years. At 10%, about 7.2 years. At 6%, about 12 years. This calculator shows the exact figure with compounding included.
Does compounding frequency matter?
More frequent compounding earns a little more, since returns start compounding sooner. Under Advanced options you can switch between annual, semi-annual, quarterly, monthly, and daily. The difference is larger at higher rates and longer horizons, and small at short ones. Monthly is a reasonable default for most investments.
Choosing a realistic return rate
Match the rate to what you are actually investing in:
- Savings accounts and CDs: 3–5%
- Government bonds: 4–5%
- Corporate bonds: 5–7%
- Broad stock index funds: 8–10% (historical long-term average)
- Individual stocks or sector funds: highly variable, not suitable for a fixed-rate projection
Using 12–15% because a specific fund performed well recently is a common planning mistake. Sustainable long-term returns are lower, and an overly optimistic assumption can leave you short of your goal.
Find-principal mode: how much to invest today
Switch to find-principal mode when you know the target and the timeline but not the starting amount. The calculator rearranges the formula to the present value — the lump sum that grows into your target at the chosen rate and time frame.
Use this mode to size a one-time investment against a goal: an inheritance you want to grow into a house deposit, or a windfall you want to turn into a retirement supplement.
Lump sum vs recurring investment
If you have a large amount available today, investing it all immediately has historically produced higher returns than dripping it in over time, because markets trend upward more often than not. However, investing everything at once means taking full market-timing risk. If the market drops shortly after, your balance drops with it.
A common compromise is investing the bulk as a lump sum and reserving a portion for recurring investment over 3–6 months. To model the recurring portion, use the SIP calculator. To measure the annual growth rate a past investment actually delivered, use the CAGR calculator.
Projections assume a constant return and are estimates, not a guarantee. Real returns vary year to year, and past performance does not predict future results.
Frequently asked questions
Lump sum or invest gradually — which is better?
Historically, investing a lump sum immediately beats dripping it in (dollar-cost averaging) about two-thirds of the time, because markets trend upward. However, DCA reduces timing risk. If losing 20% shortly after investing would cause you to panic-sell, spreading it over 3–6 months may be a better fit emotionally.
How long does it take to double my money?
Use the Rule of 72: divide 72 by your annual return. At 8%, your money doubles in about 9 years. At 10%, about 7 years. At 6%, about 12 years. This calculator shows the exact figure with compounding.
What return rate should I use for planning?
Match it to your asset. Savings accounts: 3–5%. Bonds: 4–6%. Broad stock index funds: 8–10% long-term. Avoid using a recent high return (12–15%) as your baseline — sustainable long-term returns are lower. Use a conservative figure when setting goals.
How is this different from the compound interest calculator?
This tool is for a single lump sum with no ongoing contributions. If you add money regularly (say monthly), use the compound interest calculator or SIP calculator, which model recurring contributions, step-ups, and one-time events.
Does this account for taxes?
No. The projection is pre-tax. Actual returns depend on your account type and jurisdiction — tax-advantaged accounts shelter gains, while taxable accounts owe capital gains tax on withdrawal. Treat the result as a gross estimate.