Text with personality
Turn plain words into tiny, raised, mirrored and symbol text you can paste anywhere.
Browse fancy textQuick calculators
Percentages, money, grades, math, age, sleep and time tools.
Browse all calculatorsNumber and code tools
Binary, hex, Roman numerals, Base64, URL encoding and passwords, all in your browser.
Browse all calculatorsEnter an amount, a rate and a term, add deposits if you like, and see the balance, a yearly schedule and the formula. It also converts APR to APY.
| Period | Deposits | Interest | Balance |
|---|
Same amount, deposits and term at rates 2 points lower to 2 points higher. Tap a rate to use it.
| Rate | Balance | Interest | Change |
|---|
Each row is the nominal rate that gives the same effective annual yield as your rate.
| Compounded | Nominal rate | Per period |
|---|
Private by design. Everything runs in your browser and is never uploaded. Results are estimates.
Compound interest is interest paid on your original amount and on the interest already added to it. The formula is A = P(1 + r/n)nt, where P is the starting amount, r the yearly rate as a decimal, n the compounding periods a year and t the years. For example, 10,000 at 5% compounded monthly for 10 years becomes 16,470.09.
Because the interest from each period joins the balance, the next period earns interest on a larger amount. This compound interest calculator adds regular deposits at the start or end of each period, supports nine compounding schedules from daily to continuous, shows a yearly or monthly schedule and a chart, and converts between APR and APY. Results update as you type. For other everyday sums, see the free online calculators, or use the percentage calculator to turn a rate into a percent change.
| Example | Balance | Interest |
|---|---|---|
| 10,000 at 5%, monthly, 10 years | 16,470.09 | 6,470.09 |
| 1,000 at 6%, yearly, 2 years | 1,123.60 | 123.60 |
| 1,000 at 6%, daily, 2 years | 1,127.49 | 127.49 |
| 10,000 at 5%, monthly, plus 200 a month at month end, 10 years | 47,526.55 | 13,526.55 |
| Same, with each deposit at month start | 47,655.95 | 13,655.95 |
| 1,000 at 5%, continuous, 10 years | 1,648.72 | 648.72 |
The first answer is already on screen. Change any number and everything updates at once, with no Calculate button.
Type the starting amount, the yearly interest rate and the term in years and months. Commas for thousands are fine, and 5,5 is read as 5.5.
Choose how often interest is added, from daily to yearly, or continuously. The effective yield (APY) of your rate is shown under the result.
Enter a deposit, how often it is made, and whether it lands at the start or the end of each period. Leave it empty for a one-off amount.
See the balance, the chart, the schedule and the formula with your numbers. Copy the result, download the schedule as CSV, or share a link that opens with the same inputs.
Divide the yearly rate by the number of compounding periods, add 1, raise the result to the power of periods per year times years, and multiply by the starting amount. For 10,000 at 5% compounded monthly for 10 years, 0.05 / 12 = 0.0041667, 1.0041667 to the power 120 is 1.6470095, and 10,000 × 1.6470095 = 16,470.09. Interest is the final amount minus the starting amount.
Regular deposits add a second term. First find the growth rate for one deposit period, i, then multiply the deposit by ((1 + i)N − 1) / i, where N is the number of deposits. Deposits at the start of a period are multiplied by one more (1 + i), because each earns an extra period of interest. The tool shows both terms with your numbers under Show the formula with your numbers.
Amounts are rounded to the nearest cent, halves up, only when they are shown. The calculation itself runs unrounded in double-precision arithmetic and was checked against 506 high-precision reference calculations with no differences. To see how rounding rules work in general, try the rounding calculator.
| Value | Formula |
|---|---|
| Final amount | A = P(1 + r/n)nt |
| Continuous compounding | A = P ert |
| Interest earned | A − P |
| Growth per deposit period | i = (1 + r/n)n/m − 1, with m deposits a year |
| Deposits at the end of each period | C × ((1 + i)N − 1) / i |
| Deposits at the start | C × (1 + i) × ((1 + i)N − 1) / i |
| APY from a nominal rate | (1 + r/n)n − 1, or er − 1 |
| Nominal rate from APY | n × ((1 + APY)1/n − 1), or ln(1 + APY) |
| Time to double | ln 2 / (n × ln(1 + r/n)), roughly 72 / rate |
| Value after inflation | A / (1 + inflation)t |
Two tables you can check by hand. Figures are rounded to the cent and work for any currency.
| Compounded | Final balance | Interest | Effective yield (APY) |
|---|---|---|---|
| Annually | 16,288.95 | 6,288.95 | 5.00% |
| Semi-annually | 16,386.16 | 6,386.16 | 5.063% |
| Quarterly | 16,436.19 | 6,436.19 | 5.095% |
| Monthly | 16,470.09 | 6,470.09 | 5.116% |
| Weekly | 16,483.25 | 6,483.25 | 5.125% |
| Daily | 16,486.65 | 6,486.65 | 5.127% |
| Continuously | 16,487.21 | 6,487.21 | 5.127% |
| Rate | 5 years | 10 years | 20 years | 30 years |
|---|---|---|---|---|
| 2% | 11,050.79 | 12,211.99 | 14,913.28 | 18,212.09 |
| 4% | 12,209.97 | 14,908.33 | 22,225.82 | 33,134.98 |
| 6% | 13,488.50 | 18,193.97 | 33,102.04 | 60,225.75 |
| 8% | 14,898.46 | 22,196.40 | 49,268.03 | 109,357.30 |
| 10% | 16,453.09 | 27,070.41 | 73,280.74 | 198,373.99 |
Many compound interest calculators ask for an amount, a rate and a number of years and stop there. These are the details that change the answer.
| Feature | Basic calculator | This calculator |
|---|---|---|
| Results | Often needs a Calculate button | Updates as you type, with an answer on first load |
| Compounding choices | Often four or five, sometimes tied to the deposit schedule | Nine, from daily to continuous, chosen separately from the deposit schedule |
| Deposits | Often monthly only, timing not stated | Eight frequencies, at the start or the end of each period |
| Term | Whole years | Years and months, up to 100 years |
| Schedule | Yearly table, if any | Yearly or monthly table with a CSV download |
| Formula | Shown as a general formula | Worked with your numbers, step by step |
| APR and APY | A separate page | Built in, in both directions, at nine frequencies |
| Extras | Rarely | Rate what-if table, goal date, inflation, share link |
| Rounding rule | Usually not stated | Stated: nearest cent, halves up, every row adds up |
Enter the quoted rate and the compounding schedule to see the balance at the end of the term, and the APY that results.
One offer quotes a rate compounded monthly and another quotes a yield. Convert both to APY in the converter and compare like with like.
See how a few points of rate change the balance in the what-if table, and use the reference tables on this page to compare 5, 10, 20 and 30 years.
The same maths applies to a balance that is left unpaid and charged interest. Check your own statement for the real rate and how it is compounded.
Enter a goal balance under More options to see the month in which it is first reached with your deposits.
The formula is worked out with your numbers, so you can follow each step and check an answer. Paste results into the online notepad to keep them.
This page does not tell you how to invest or save. It does the arithmetic, and these points help you read the answer.
Moving from monthly to daily compounding adds about 16.56 to 10,000 at 5% over 10 years. Moving the rate from 5% to 6% adds far more.
A 6% rate compounded monthly is 6.16778% APY. When two offers quote different compounding, compare their APY.
A deposit at the start of a period earns one extra period of interest. In the 200 a month example that is about 129.40 more over 10 years.
The calculator assumes one fixed rate for the whole term. Real accounts and investments change, so treat every result as an estimate.
None are included unless you enter inflation. Fees and taxes lower what you keep, and inflation lowers what the balance buys.
Nothing you type leaves your browser. After the page loads, the calculator keeps working without a connection.
The rate and the deposit stay the same for the whole term. There are no withdrawals, no deposit increases and no rate changes. Run several scenarios for those.
It shows what the formula gives, not what an account will pay. Past or typical returns are not a forecast, and nothing here is a recommendation.
Banks set their own crediting schedule and day count. For how deposit accounts must calculate APY in the US, see Appendix A to Regulation DD. A loan APR can also include fees, so it is not the same as the nominal rate here.
The calculations are the standard formulas below, checked against the worked examples on this page and 506 reference calculations done separately in high-precision arithmetic. Definitions and formulas come from these references.
Short answers to common questions about compounding, deposits and APY.
The formula is A = P(1 + r/n)^(nt). A is the final amount, P the starting amount, r the yearly rate as a decimal, n the number of times interest is compounded each year and t the number of years. For 10,000 at 5% compounded monthly for 10 years, A = 10,000 × (1 + 0.05/12)^120 = 16,470.09.
Each deposit starts earning interest from the day it is added, so earlier deposits grow the most. Adding 200 at the end of every month to 10,000 at 5% compounded monthly gives 47,526.55 after 10 years, of which 34,000.00 is money you put in and 13,526.55 is interest.
Not much. On 10,000 at 5% for 10 years, daily compounding gives 16,486.65 and monthly gives 16,470.09, a difference of 16.56. The rate and the number of years matter far more than how often the interest is added.
APR here means the nominal yearly rate before compounding, and APY is the effective yearly rate after compounding. A 6% rate compounded monthly is 6.16778% APY, which US deposit rules show as 6.17%. Banks often quote APY for savings because it is the higher number.
Use APY = (1 + r/n)^n − 1. For 5% compounded monthly, (1 + 0.05/12)^12 − 1 = 0.0511619, or 5.11619%. Switch the calculator to APR / APY mode to convert in either direction, or to see the same yield at every compounding frequency.
That depends on when your money actually lands, so the calculator lets you choose. Deposits at the start of each month earn one extra month of interest each. In the 200 a month example above the start option ends at 47,655.95, which is 129.40 more than the end option.
It is the limit of compounding more and more often, and the formula becomes A = Pe^(rt). 1,000 at 5% compounded continuously for 10 years grows to 1,648.72, only slightly above daily compounding. It is a mathematical upper bound and rarely used by real accounts.
The exact time is ln 2 divided by (n × ln(1 + r/n)) years. The rule of 72 estimates it as 72 divided by the percentage rate, so about 12 years at 6%, where the exact answer is about 11.9 years. The calculator shows both for your rate.
Simple interest is paid only on the starting amount, while compound interest is also paid on interest already earned. 10,000 at 5% for 10 years earns 5,000.00 of simple interest, but 6,470.09 of interest when compounded monthly.
Taxes and fees are not included, so real results can be lower. You can enter an inflation rate under More options to see what the final balance is worth in today money. All results are estimates, not predictions or guaranteed returns.
Banks can credit interest on their own schedule, count days in the year differently, round every period, or change the rate over time. This calculator assumes one fixed rate and applies the compounding formula directly, so small differences are normal.
No. The calculation runs in your browser and nothing is sent to a server. Your numbers appear in the page address only if you use Share link, and your currency choice is remembered on your own device.