What a lump sum grows to at a fixed rate.
FV = PV × (1 + r)^n
The future value of a lump sum is calculated using the compound interest formula. It multiplies the present value by a growth factor that compounds the interest rate over each period. The more periods and the higher the rate, the larger the compounding effect — this is why time in the market matters enormously for wealth building.
FV = 10,000 × (1 + 0.07)^20 = 10,000 × (1.07)^20 = 10,000 × 3.86968... ≈ 10,000 × 3.8697
Result: FV ≈ $38,697
After 20 years, your original $10,000 lump sum grows to approximately $38,697 at a steady 7% annual compound rate. That means the investment generated roughly $28,697 in interest — nearly three times the original principal — purely through compounding. This illustrates the power of long-term compound growth: your money more than triples without any additional contributions.
Future value answers the question: "If I invest a sum of money today, how much will it be worth later?" It is one of the most fundamental concepts in personal finance and investing, forming the basis for retirement planning, college savings, and any long-term wealth-building strategy.
The key driver of future value is compound interest — earning interest not just on your original principal, but on all the interest that has already accumulated. Albert Einstein is often (apocryphally) credited with calling compound interest the "eighth wonder of the world." Whether or not he said it, the math backs it up: at 7%, money doubles roughly every 10.2 years (using the Rule of 72: 72 ÷ 7 ≈ 10.3 years).
The more frequently interest compounds, the faster the investment grows — though the difference between annual and daily compounding is often modest for typical rates. For example, $10,000 at 7% for 20 years:
This calculator uses a nominal rate (the stated rate). In the real world, inflation erodes purchasing power. To find the inflation-adjusted (real) future value, subtract the inflation rate from the nominal rate before entering it — e.g., if your return is 7% and inflation is 3%, use 4% as your real rate.
Disclaimer: Results from this calculator are mathematical estimates based on a constant, fixed rate. Actual investment returns vary and are never guaranteed. This tool does not constitute financial advice. Consult a licensed financial advisor before making investment decisions.
Use the **Rule of 72**: divide 72 by the annual interest rate. At 6%, money doubles in 72 ÷ 6 = 12 years. At 10%, it doubles in about 7.2 years. This rule is an approximation; the exact answer uses the formula n = ln(2) ÷ ln(1 + r).
FV = 5,000 × (1.05)^10 = 5,000 × 1.6289 ≈ **$8,144**. The $5,000 investment earns approximately $3,144 in compound interest over 10 years.
Even a 1% difference compounds significantly over time. For example, $10,000 over 30 years at 6% grows to ≈$57,435, while at 7% it grows to ≈$76,123 — a difference of nearly $19,000 from just one extra percentage point.
They are closely related but not identical. Compound interest is the *interest earned* on a growing balance, while future value is the *total balance* (principal + all compound interest). FV = PV + total compound interest earned.
More frequent compounding increases FV because interest is added to the principal more often, creating a larger base for subsequent interest calculations. The limit of infinitely frequent compounding is *continuous compounding*, given by FV = PV × e^(r×n), where e ≈ 2.71828.
Present Value (PV) is what money is worth *today*, while Future Value (FV) is what that money will be worth at a *future date* after earning compound interest. They are inverse calculations: if you know FV, you can discount it back to PV using the formula PV = FV ÷ (1 + r)^n.
Yes. For monthly compounding, enter the monthly interest rate (annual rate ÷ 12) as r and the total number of months (years × 12) as n — or use the compounding frequency selector if available. For example, 7% annual compounded monthly means r = 0.07/12 ≈ 0.5833% per month.
The U.S. stock market (S&P 500) has historically returned roughly 7–10% per year in nominal terms (about 7% inflation-adjusted) over long periods. However, past performance does not guarantee future results. For conservative planning, many financial planners use 6–7% nominal.
Absolutely. Enter your deposit as PV, the account's APY as the interest rate, and the term in years as n. For CDs or savings accounts, annual or daily compounding is typical — check your account terms for the exact compounding frequency.
The calculator is mathematically exact for the inputs you provide. However, real-world results differ because interest rates change, inflation erodes purchasing power, taxes apply to gains, and fees reduce net returns. Use the result as a planning benchmark, not a guaranteed outcome.
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