Compound interest calculator with inflation: what your money is really worth

You earn interest on your interest. What your money earns gets added to the capital, and next year that bigger amount earns too. That's why the first years feel slow and the last ones add the most.

Multiply the balance by one plus the yearly rate, and repeat once for every year. 10,000 at 10% for 10 years is 10,000 × 1.1^10 = 25,937. With contributions, each one grows from the day it goes in. The calculator does that in half-month steps, and the sums are written out in "How we calculate it and how to check it."

Only if your return, after fees, is higher than inflation. Inflation compounds too, but against you: every year your money buys a little less. Compare the two lines in the worked example above, the value before taking out inflation and the value in today's money. The distance between them is what inflation takes.

Real return is what's left after inflation. The quick way is to subtract: 8% return minus 3% inflation is about 5% real. The exact way is to divide: 1.08 ÷ 1.03 − 1 = 4.85%. Take the fees out first. The calculator gives you the real return after fees and inflation, right under the result.

Calculate the compound balance first, then divide it by (1 + inflation) raised to the number of years. 25,937 after 10 years with 3% inflation is 25,937 ÷ 1.03^10 = 19,300 in today's money. The calculator does it for you with your country's official inflation.

It depends on how often the interest is added: every day, every month or every year. With an effective annual rate the result is the same whichever you pick. With a nominal rate (APR), the more often it compounds, the more it earns. The difference is small next to inflation and fees, and the sums are in "How we calculate it and how to check it."

Later than you'd expect. In the first years, most of the balance is what you put in. The interest becomes the bigger part after a decade or two, depending on the rate. Open the year-by-year table under the result and look for the year when the interest passes what you put in.

Simple interest is paid only on the original amount, so 1,000 at 5% pays 50 every year. Compound interest is paid on the original amount plus the interest already earned, so the second year pays on 1,050. Over a short time the difference is tiny. Over twenty years it's big.

Yes. Debt you don't pay off compounds the same way, and credit card rates are much higher than what an investment usually earns. Fees work against you too: a fund's yearly fee comes out of everything you have invested, so it compounds against you.

It does, but a stock doesn't pay a fixed rate. The price goes up and down, and what compounds is the return you keep, including the dividends you reinvest. That's why the calculator gives you three scenarios and not one number, and why holding through the bad years matters. The return is never a given.

APY (United States), AER (United Kingdom) and the effective annual rate (Canada, Australia, India) already include compounding, and those are what the calculator uses by default. APR and other nominal rates don't include it: if that's the one you have, pick "Nominal annual rate" in "More options" and set its compounding. Be careful not to type a yearly rate as if it were monthly.

The rule of 72: divide 72 by the return and you get roughly the years. What matters is how long it takes for what you can buy to double, so use the real return: at 3% real, about 24 years. The calculator tells you under the result.

It depends on how much you want to spend each month and on the years you have left, so there's no single number that fits every case. In the "How much do I need to contribute?" tab you type your goal in today's money, and the calculator tells you how much to contribute each month to get there.

Fees yes, and it shows you what they cost in money at the end. Taxes no, because they change with the country and the product, so the result is before taxes.

If you contribute at the start of the month, each contribution works one month longer. The difference is small, but it compounds too. You change it in "More options", under "When".

Pick the country of the currency you invest in, and the calculator uses that country's inflation. If you convert back later, you add exchange-rate risk, and the calculator doesn't work that out.

No. Everything is calculated on your phone or your computer, with no cookies and no ads. The share link carries your numbers only if you copy it or share it yourself.