Questions and answers

Your money earns a return, and that return is added to your balance, so next year it earns a return too. At first growth is slow, because most of the balance is money you put in. Over time the earnings on earlier earnings grow larger than your own deposits. With 1,000 to start and 200 a month at 10% a year, that happens in year 13, and after 30 years the balance is about 471,935, of which 73,000 is what you put in. The formula for one amount is A = P × (1 + r/n)^(n × t): starting amount P, yearly rate r, n compounding periods a year, t years. The methodology adds monthly deposits, fees and tax. Time matters most, as starting at 25 instead of 35 shows.

Open Compound interest calculator

This page keeps three inputs: what you put away, what you start with and the yearly return, with interest added monthly. It answers the basic question of how savings grow. The compound interest calculator for investments adds everything that shapes a real investment: return presets for savings accounts, bonds and index funds, eleven compounding frequencies with the effective yearly rate, fund fees, tax on gains, inflation in today's money, a market risk band and up to three plans side by side. The link under the result opens it with your numbers already filled in, so nothing has to be typed twice.

Open Compound interest calculator

A quick way to estimate how long money takes to double: divide 72 by the yearly return in percent. At 10% that gives 7.2 years; the exact answer is about 7.27 years. At 7% the rule gives about 10.3 years, which is why a gift invested at birth keeps doubling for decades. The calculator shows the estimate for the return you choose.

Open Compound interest calculator

No. The calculator runs in your browser and does not send your numbers to a server. They are kept in the page address, so a reload, bookmark or shared link shows the same plan. Anyone you send the link to can see the numbers in it. There is no sign-up and no cookies.

Open Compound interest calculator

No. The calculator shows how money could grow under the assumptions you choose. It does not know your situation and does not recommend any product or decision. Real returns, fees and tax vary. For decisions about your own money, consider talking to a qualified, independent professional.

Open Compound interest calculator

It depends on the return and on how long you keep going. With 1,000 to start and 200 a month at 10% a year for 30 years, you would put in 73,000 and end with about 471,935 before fees and tax, or about 224,992 in today's money at 2.5% inflation. A lower return gives a much smaller result, so try a few rates. For smaller amounts, see saving for a child with 100 a month from birth to 18 or what 5 a day becomes in 30 years. These are illustrations; real returns vary.

Open Compound interest calculator

Broad world stock indices have grown roughly 8 to 9% a year before inflation over long periods: the MSCI World index (developed markets, dividends reinvested, in US dollars) returned about 8.5% a year from the end of 1987 to April 2025, according to MSCI's factsheet, with big swings from one year to the next. That average spans almost four decades with deep falls and long rises; it describes the past, comes before fees, tax and inflation, and does not predict future returns. 10% is above it, and no future return is known in advance. Try lower rates, or the presets for a savings account or bonds. Past returns do not promise future ones.

Open Compound interest calculator for investments

Prices tend to rise, so an amount in 30 years pays for less than the same amount today. With inflation switched on, every result is divided by how much prices have risen by that year, so it shows what the money would be worth at today's prices. At 2.5% inflation, a balance of 471,935 in 30 years is worth about 224,992 in today's money. Your statement would still show the bigger number.

Open Compound interest calculator for investments

A fee is taken every year from your whole balance, and the money taken also stops growing. On a plan of 1,000 plus 200 a month at 10% for 30 years, a 0.2% yearly fee costs about 19,987, around 4% of the result. An expensive fund charging 1.8% a year plus entry, exit and performance fees could take about 219,894, close to half. Switch on fund fees to see the effect on your own plan.

Open Compound interest calculator for investments

Taxed every year works like interest on a savings account: gains are taxed as they arrive, so less money stays invested to compound. Taxed when you sell is typical for accumulating funds: gains grow untaxed and tax is due once, on the gain, when you sell. On the default plan at 19%, yearly tax costs about 156,475 and tax at the end about 75,798. Rules differ by country, so this is an estimate, not tax advice.

Open Compound interest calculator for investments

Pick how often your account adds interest: most savings accounts and funds work monthly, bonds often pay twice a year, and some accounts credit interest daily. The effective yearly rate under the select shows what the nominal rate really becomes over a year. At 7% a year, monthly compounding gives 7.23% and daily compounding 7.25%; at 5% the figures are 5.12% and 5.13%. The difference between monthly and daily is small, but yearly versus monthly adds up over decades. If you do not know, keep monthly: it is what most products and this site's examples use. Tap any option and the chart updates.

Open Compound interest calculator for investments

It is the size of pot that could pay your planned retirement spending under the 4% rule: 25 times a year of withdrawals. Spending 1,200 a month means withdrawing 14,400 a year, so the FIRE number is 360,000. With tax on withdrawals switched on, you need to take out a little more to spend the same, so the FIRE number rises.

Open Retirement savings calculator

A rule of thumb from US research in the 1990s (a 1994 study in the Journal of Financial Planning, then the 1998 Trinity University study): take 4% of your pot in the first year of retirement, then raise that amount with prices every year. In past US market data this lasted 30 years or more in most periods. It is not a promise: future returns may be lower, retirements can last longer than 30 years, and a bad first decade matters most. The studies show what happened in past US markets, not what will happen next.

Open Retirement savings calculator

The two lines start from the same pot but take out different amounts. Your plan withdraws what you plan to spend; the 4% rule withdraws 4% of the pot a year. If your spending is more than that, the pot shrinks faster and may run out before age 100. Retiring later, spending less or saving more each month moves the date.

Open Retirement savings calculator

Only the part of each withdrawal that comes from gains is taxed, not the money you put in yourself. If 85% of the pot is gains and the tax rate is 19%, each withdrawal is taxed at about 16%, so you take out a little more to spend the same. Tax rules differ by country; this is an estimate, not tax advice.

Open Retirement savings calculator

With inflation off, amounts are shown as a statement would show them and withdrawals stay flat. Switch it on to see everything in today's money: your withdrawals then rise with prices every year so they pay for the same things, and the pot and FIRE number are shown at today's prices. The setting follows step 1 when you come from the calculator.

Open Retirement savings calculator

Financial independence, retire early. The idea is to save and invest a large share of what you earn until your investments could cover your living costs, so that work becomes a choice. Many people who get there keep working on their own terms. FIRE is a planning idea, not a product, and the numbers on this site are illustrations, not advice.

Open What is FIRE

Multiply a year of planned retirement spending by 25, which is the 4% rule turned around. Spending 1,200 a month is 14,400 a year, so the FIRE number is 360,000. The retirement calculator works it out from your own spending and shows how long a pot could last. Treat the result as a rough guide: the 25 comes from past US market data.

Open What is FIRE

Nobody knows in advance. The rule comes from US studies of past market data, a 1994 study in the Journal of Financial Planning and the 1998 Trinity University study, and covered 30-year retirements. Those studies describe what happened in the past; they do not predict future returns. Early retirees may need their money for 40 or 50 years, and studies of other countries often found lower rates, so many people treat 4% as a starting point rather than a promise.

Open What is FIRE

Having saved enough early that, without adding more, the pot could grow into your FIRE number by a normal retirement age. You still work to pay today's costs, but you no longer need to save for retirement. The example of a gift invested at birth shows the same effect: one amount left alone to grow for decades.

Open Coast FIRE calculator

Divide your FIRE number by how much money grows until retirement: Coast FIRE number = FIRE number ÷ (1 + real return)^years. With a FIRE number of 360,000, 30 years to go and a return of 5% a year after inflation, that is about 83,300. To check it, enter that amount as the starting sum in the compound interest calculator, set the monthly saving to 0 and switch on inflation. The result depends heavily on the return you assume.

Open Coast FIRE calculator

The number assumes a steady return after inflation for decades. Real markets go up and down, so a weak decade can leave the pot short. It also assumes nothing is taken out early and that your retirement spending matches the plan. That is why many people check it now and then as a milestone rather than relying on it. It is an illustration, not advice.

Open Coast FIRE calculator

Divide the goal by the number of months, then let interest lower the amount. 20,000 in 5 years with no interest means 333 a month; at 4% a year it is about 302 a month, because the early deposits earn interest for the rest of the period. The calculator solves this exactly, with deposits at the end of each month, and the full calculator shows the same plan year by year.

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Over short periods, the time. 100,000 in 10 years at 7% needs about 578 a month; in 20 years it needs about 192 a month, a third of that, because interest does more of the work. Doubling the rate helps far less than doubling the years, and a rate is a guess while the years are a choice. The Rule of 72 shows how long doubling takes at each rate.

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Enter them as the starting amount. The calculator first lets that amount grow on its own and only asks the monthly deposits to cover the rest. 10,000 today at 7% becomes about 40,387 in 20 years, so a 100,000 goal then needs about 114 a month instead of 192. If the start alone reaches the goal, the answer is 0 a month.

Open Savings goal calculator

The rate the money is likely to earn where it sits: a savings account rate for cash, a long-run average for an index fund, after fees. A fixed rate from a bank is known in advance; a market return is not, so for goals a few years away many people run the calculator with a lower rate too and plan for that result. Past returns do not promise future ones.

Open Savings goal calculator

Try different numbers of years until the monthly amount fits what you can put away. For a 20,000 goal at 7%, 4 years needs about 362 a month, 5 years about 279 and 6 years about 224. Without interest the same goal at 300 a month takes 20,000 ÷ 300, about 67 months.

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Your retirement number, also called the FIRE number (financial independence, retire early), is 25 times your yearly spending, because of the 4% rule of thumb: a pot that pays out 4% a year covers yearly spending equal to 1/25 of its size. Spending 1,200 a month, or 14,400 a year, points to a target of 360,000. The 4% figure comes from US market studies of 30-year retirements (a 1994 article in the Journal of Financial Planning and the 1998 Trinity University study). It is a rule of thumb, not a guarantee; a lower rate such as 3% means a larger target.

Open How much do I need to retire

Yes. Enter only the spending the savings have to cover. If you expect 600 a month from a state pension and want to spend 1,800, the savings cover 1,200 a month and the target is 360,000, not 540,000. The same goes for rent from a property or a part-time income. The calculator does not estimate pensions; it works with the gap you enter.

Open How much do I need to retire

The target is in today's money: the spending you enter is what you would spend now, and the 7% return here is meant as a return above inflation plus costs. Tax on withdrawals depends on where you live and how the money is held. The retirement calculator has switches for inflation, fees and a tax rate on the gain, so you can see how far each one moves the target.

Open How much do I need to retire

Under the 4% rule of thumb, 1% of the pot every three months, which is a third of a percent a month: 360,000 pays about 1,200 a month, 500,000 about 1,667 and 1,000,000 about 3,333. That rate is meant to keep the pot going for about 30 years through good and bad markets. It is a rule of thumb from US market studies (a 1994 article in the Journal of Financial Planning and the 1998 Trinity University study), not a guarantee, and the money has to stay invested for it to apply.

Open Retirement income

Exactly as long as you set, and the monthly amount follows from that. 360,000 at a 5% return pays about 2,354 a month for 20 years or about 3,799 for 10 years, with nothing left afterwards. The 4% rule's 1,200 a month is lower because it aims to leave the pot intact. The page shows all three so you can see the trade-off between a higher income and a longer one.

Open Retirement income

Often partly. In many countries only the gain inside each withdrawal is taxed, not the deposits you put in, and some holding periods or account types are exempt. The figures on this page are before tax. The retirement calculator has a tax switch that applies a rate to the gain part of each withdrawal.

Open Retirement income

It grows the savings year by year at the chosen return and stops at the first year in which they reach 25 times the yearly spending, the target from the 4% rule of thumb. The age is your current age plus those years. If the savings never get there within 80 years, the page says so instead of showing an age.

Open When can I retire

Spending, in both directions. Lower spending shrinks the target and raises the amount that can be saved at the same time, so each 100 a month less in retirement removes 30,000 from the target. Saving more works too, but only on the second half of that effect. The return matters, but it is the one input you do not control.

Open When can I retire

No. It is arithmetic on the numbers you enter with one fixed return every year. Real returns come in uneven years, and a bad run just before the target can push the date back by years. Treat the age as a planning figure and rerun the page with a lower return to see the range. The retirement calculator adds inflation, fees and tax to the picture.

Open When can I retire

The answer the page gives is the age at which your savings reach 25 times your yearly spending, whatever that age is. An early retirement has to last longer than the 30 years the 4% rule was tested on, so many people plan a longer one with a lower rate, such as 3%, which raises the target to 33 times yearly spending. The retirement calculator lets you set the rate and see how long the pot lasts.

Open When can I retire

The nominal rate is the yearly figure a bank or fund quotes. The effective rate is what you actually get in a year once interest is added more than once and starts earning on itself. 5% compounded monthly gives 5.12% effective; compounded daily, 5.13%. The gap grows with the rate: 10% monthly is 10.47% effective.

Open Effective annual rate

It is the only fair way to compare two offers that compound differently. A 5% rate added quarterly (5.09% effective) beats a 5.05% rate added once a year. The same arithmetic applies to loans, where a quoted rate charged monthly costs more than the same rate charged yearly. The full calculator shows the effective rate under its compounding setting.

Open Effective annual rate

Effective rate = (1 + r ÷ n)^n − 1, where r is the nominal yearly rate and n the number of times interest is added each year. For 5% monthly: (1 + 0.05 ÷ 12)^12 − 1 = 0.0512, or 5.12%. As n grows, the result approaches e^r − 1, so daily and continuous compounding differ by almost nothing.

Open Effective annual rate

Yes. APY, the annual percentage yield, is what US banks call the effective annual rate: 5% compounded monthly is a 5.12% APY. In Europe the same figure is often called AER. A nominal rate quoted as APR leaves the compounding out, so accounts compare fairly on APY or the effective rate.

Open Effective annual rate

A shortcut for how long money takes to double: divide 72 by the yearly rate in percent. At 7% it says about 10.3 years; the exact answer is 10.2. At 2% it says 36 years against an exact 35. It works in reverse too: to double in 10 years takes about 7.2% a year. The page shows both the shortcut and the exact figure for your rate.

Open Rule of 72

Within a few months for rates between about 4% and 12%, which covers most savings and investing questions. It drifts at the ends: at 24% it says 3 years where the exact answer is 3.2, and at 1% it says 72 years against an exact 69.7. The exact formula is ln 2 ÷ ln(1 + r), and the calculator uses that for its second answer.

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Yes, for anything that compounds. Inflation of 3% halves what money buys in about 24 years. A fund fee of 1% a year takes about a tenth of the result over 10 years and about a quarter over 30 (7% against 6% a year, no deposits); the glossary compares 0.2% and 1% in the calculator. The rule also says why a return a few points lower makes such a difference over decades: each doubling takes years longer.

Open Rule of 72