Daily Compounding Calculator

See what your money grows to when interest is added every day. Enter the principal, annual rate, and days — or pick dates. At 10,000, 5%, and 365 days you get 10,512.67. In options you can estimate tax on interest and compare monthly and annual compounding.

Result

Enter the principal, rate, and number of days, then Calculate.

This is not a bank deposit and not a tax filing. The calculator uses A = P × (1 + r/365)^days. For interest added once a year, use compound interest. For month-based terms, try the deposit page or interest with compounding.

How the results are calculated

10,000 × (1 + 0.05/365)³⁶⁵ ≈ 10,512.67

P10000

(1+r/365)^d(1+0.05/365)³⁶⁵

→

A10512.67

With daily compounding, interest is added once a day. This calculator assumes a 365-day year. The formula is A = P × (1 + r/365)^days. For 10,000 at 5% over 365 days you get 10,512.67, of which 512.67 is interest.

Principal is your starting amount. Enter the annual rate in percent — the calculator divides by 100 and by 365 to get the rate for one day. The day count must be greater than zero; an empty field or zero shows a message next to Number of days instead of quietly assuming a full year. At 20,000, 4%, and 180 days the result is 20,398.42.

On the compound interest page, interest is added once a year over several years — for example 10,000 at 6% for 10 years. A deposit tool usually works in months and may subtract tax. Monthly compounding at 10,000, 5%, and 12 months is about 10,511.62. Here the same principal and 5% for 365 days give 10,512.67, because interest is added 365 times, not 12.

Enter 10000, 5, and 365, then click Calculate. You can type the rate with a comma (5,5) or a decimal point (5.5). Result amounts use the currency from the header. This is a formula estimate — not a bank offer and not a tax filing.

Third example: 5,000 at 6% for 730 days gives 5,637.43. A different day count or rate changes the result; the method stays the same.

Formula

Interest added every day, assuming a 365-day year.

A = P × (1 + r/365)^days, where r is the annual rate in percent divided by 100, and days is the positive whole number from the form.

Interest = A − P. By default the result is gross. Tax on interest is subtracted only after you turn on the option. Bank fees are not included.

How to use

In field 1 enter the principal, for example 10000.
In field 2 enter the annual rate in percent, for example 5.
In field 3 enter the number of days, or switch to dates. The 30 / 90 / 180 / 365 / 730 buttons set the term right away.
Under More options you can add a tax estimate and a comparison with monthly and annual compounding.
Click Calculate. At 10000, 5%, and 365 days you should see 10,512.67 — with a chart and comparison under the result.

What the formula symbols mean

A = P × (1 + r/365)^days. 10,000 at 5% for 365 days gives 10,512.67. Tax is off by default — you can turn it on in the form.

P: Starting principal. 10,000 at 5% for 365 days ends at 10,512.67.
r/365: The rate for one day. At 5% a year that is 0.05 divided by 365.
days: How many times interest is added. Fractions are rounded down. 180 days at 20,000 and 4% gives 20,398.42; 730 days at 5,000 and 6% gives 5,637.43.
interest: Ending balance minus principal. In the first example that is 512.67.

Examples

Example 1

principal 10,000
rate 5%
365 days

10,512.67

10,000 × (1 + 0.05/365)^365 ≈ 10,512.67; interest 512.67.

Example 2

principal 20,000
rate 4%
180 days

20,398.42

Half a year with interest added daily: 20,000 × (1 + 0.04/365)^180 ≈ 20,398.42.

Example 3

principal 5,000
rate 6%
730 days

5,637.43

Two years (730 days): 5,000 × (1 + 0.06/365)^730 ≈ 5,637.43.

Related calculators

Frequently asked questions

How does daily compounding work on this page?

The calculator uses A = P × (1 + r/365)^days. It turns the annual percent into a decimal (5% → 0.05), then divides by 365. At 10,000, 5%, and 365 days you get 10,512.67, and interest is 512.67.

Why is 365 in the formula instead of 12?

Because interest is added every day, not every month. That is why the denominator is 365. Monthly compounding and month-based terms are on the interest-with-compounding page and on the deposit page.

What if the days field is empty or 0?

You will see a message next to Number of days. After you fill it in, the day count must be positive. If you use dates, the end date must come after the start date.

Does the result withhold tax on interest?

Not by default. Turn on the tax option and enter a rate to subtract tax from interest only. It is an educational estimate, not a 1099 or a tax return.

How is this different from annual compound interest?

Annual compound interest adds interest once a year over several years. Here you enter a day count and divide the rate by 365 — no contributions and no separate years field.

How is this different from a deposit calculator?

A deposit tool usually works in months and may include a tax estimate. Here you only enter principal, annual rate, and days, with interest added daily.

Does a comma in the rate, such as 5,5, work?

Yes. 5,5 and 5.5 mean the same rate. The result still uses the currency from the header.

Is 10,512.67 a bank offer?

No. It is an educational formula result. A bank may count days differently, add fees, or quote another rate.

What does the interest field next to the end value show?

It is the ending balance minus the principal. At 10,000, 5%, and 365 days that is 512.67.

Does the header currency change the formula?

No. It only changes how amounts are written. The formula A = P × (1 + r/365)^days stays the same.

November 5, 2026 · Hubert Ligocki

At 10,000, 5%, and 365 days, daily compounding gives 10,512.67 (interest 512.67).

Knowledge sources

Daily compounding is compound interest with interest added every day. We assume a 365-day year. This is not a bank deposit.

Page updated November 5, 2026.