Compound Interest Calculator — Free, No Account, Private
Calculate compound interest with annual, semi-annual, quarterly, or monthly compounding. See total balance and total interest earned over any period. Runs in your browser — your financial data never leaves your device.
Jak używać tego narzędzia
- Wprowadź kapitał początkowy, roczną stopę procentową i okres czasu.
- Wybierz częstotliwość kapitalizacji (codziennie, miesięcznie lub rocznie).
- Zobacz łączne saldo i łączne naliczone odsetki.
Future value
€16,288.95
About Compound Interest Calculator
Compound interest is interest earned on both your original principal and on the interest already added, so growth accelerates over time. This calculator uses the standard formula A = P(1 + r/n)^(nt), where A is the future value, P is the starting principal, r is the annual interest rate as a decimal, n is the number of compounding periods per year, and t is the number of years. It also reports the total interest earned (A − P) and the percentage growth over the period. The compounding frequency you can choose is annually (n = 1), semi-annually (n = 2), quarterly (n = 4), or monthly (n = 12).
The power of compounding shows up over long horizons. Put 10,000 at 6% for 30 years and, compounded annually, it grows to about 57,435, an interest gain of roughly 47,435 even though you never added another cent. The same principal at simple interest would earn only 18,000 in interest over the same period, so the extra 29,000-odd comes purely from interest earning interest. The longer the time and the higher the rate, the more dramatic the gap, which is why starting early matters far more than most people assume. Time, not the size of the initial deposit, does the heavy lifting.
Compounding frequency has a smaller but real effect: the more often interest is added, the sooner it starts earning more interest. At 6% on 10,000 over 30 years, annual compounding gives about 57,435 while monthly compounding gives about 60,226 — a meaningful difference, but far smaller than the effect of the rate or the time horizon. This is also why a quoted nominal rate and the effective annual rate differ: 6% compounded monthly is an effective yield of about 6.17% per year. When comparing savings or investment products, compare effective rates, not just headline nominal rates with different compounding.
Use the tool to plan a savings goal, project an investment, or simply understand how a balance grows untouched. Note its limits: it models a single lump sum with no regular contributions, no withdrawals, and a constant rate, so it does not handle monthly deposits, fees, or variable returns. It also ignores inflation and tax, both of which reduce real returns — a 6% nominal return with 2% inflation is closer to 4% in today's purchasing power, and interest may be taxable. Real investment returns are not fixed and can be negative, so treat projections as illustrations rather than guarantees. Everything is calculated in your browser and no figures are sent anywhere.
Często zadawane pytania
- What is compound interest?
- It is interest calculated on both your original principal and on the interest already accumulated. Because each period's interest is added to the balance and then itself earns interest, the balance grows faster over time than it would under simple interest, which only ever pays interest on the original principal.
- What formula does this calculator use?
- It uses A = P(1 + r/n)^(nt), where A is the final amount, P is the principal, r is the annual rate as a decimal, n is the number of compounding periods per year, and t is the number of years. Total interest is A − P, and the growth percentage is that interest divided by the principal.
- How much does compounding frequency matter?
- More frequent compounding produces slightly higher returns because interest starts earning interest sooner. The effect is real but modest: on 10,000 at 6% over 30 years, annual compounding gives about 57,435 and monthly about 60,226. The interest rate and the length of time matter far more than how often it compounds.
- What compounding options are available?
- You can choose annually (once per year), semi-annually (twice), quarterly (four times), or monthly (twelve times). Select the frequency that matches your account or investment so the projection reflects how interest is actually credited.
- What is the difference between nominal and effective rate?
- The nominal rate is the headline annual figure before compounding; the effective annual rate reflects the actual yield once compounding is applied. For example, 6% compounded monthly gives an effective rate of about 6.17%. When comparing products with different compounding frequencies, compare effective rates for a fair comparison.
- Does this account for regular contributions?
- No. This calculator models a single lump sum left to grow. It does not add recurring monthly deposits or handle withdrawals. If you save regularly, the true future value would be higher than the figure shown here, since each contribution would also compound over its remaining time.
- Does it account for inflation and tax?
- No. The result is a nominal figure before inflation and tax. Inflation erodes purchasing power, so a 6% nominal return with 2% inflation is closer to 4% in real terms, and interest earned may be taxable depending on the account and jurisdiction. Subtract those to gauge your real, after-tax growth.
- Are my inputs saved or sent anywhere?
- No. The calculation runs entirely in your browser. Your principal, rate, term, and frequency are never uploaded, stored, or shared, and no account is required.
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