How to Use the Daily Compound Interest Calculator

This calculator is designed to be quick and simple. You only need three pieces of information.

1. Enter your starting amount. Type the amount of money you are starting with, such as $34,500.
2. Enter your annual interest rate. Enter the percentage without the percent sign. For example, enter 7 for a 7% annual interest rate.
3. Enter the number of days. Enter 1 for one day, 30 for approximately one month, 365 for one year, or any other number of days you want to calculate.
4. Click CALCULATE. Your estimated interest earned and new balance will appear immediately.

What Is Daily Compound Interest?

Daily compound interest means that interest is calculated and added to your balance every day. Once the interest is added, it becomes part of the balance used to calculate future interest.

This is different from simple interest. With simple interest, interest is generally calculated only on the original principal. With compound interest, you can earn interest on your original principal as well as previously accumulated interest.

For example, if your starting balance earns interest today, that interest is added to the balance. Tomorrow’s calculation uses the slightly larger balance. This process continues for every day included in your calculation.

How Daily Compound Interest Is Calculated

The calculator uses the standard daily compounding formula:

A = Ending balance
P = Starting principal
r = Annual interest rate as a decimal
d = Number of days

Common Time Periods

You can use the calculator for short or long periods. For example:

• 1 day – See approximately how much interest is earned today.
• 7 days – Estimate one week of compounded interest.
• 30 days – Estimate approximately one month.
• 365 days – Calculate approximately one year.
• 730 days – Calculate approximately two years.