How to Calculate Return on an Investment for "X" Days

Sometimes it is necessary to know the return on an investment for a specific number of days.

For example, if you invest in money market funds or certificates of deposit (CDs), the term may be measured in days. Even when trading long-term bonds, you may need to know the accrued interest since the last coupon date. (Accrued interest is the return on the investment.) The Ultimate Financial Calculator can calculate the return over a specified number of days. This tutorial illustrates how to perform that calculation.

In this example, we assume you need to determine the return for a fixed number of days, but you do not know the future value date. In other words, you want to calculate the interest earned over 92 days, but you are unsure of the exact date that is 92 days after the investment begins. Step 4 shows how to calculate that final (FV) date. If you already know the FV date, skip steps 4D and 4E and enter 1 for frequency.

All users should work through the more detailed first tutorial to understand the Ultimate Financial Calculator’s (UFC) basic concepts and settings.

To calculate the return for a specific number of days, follow these steps:

1. Set Schedule Type to “Savings”.
   • Or click the New button to clear any previous entries.
2. Set Rounding to “Open balance—no adjustment”.
   Select Settings > Rounding Options.
3. Set initial values for the investment cash flow in the header section.
   • Both the interest rate and compounding method can be changed on later dates (see tutorial #4).
   1. Enter 5.3 for Initial Interest Rate (5.3%).
   2. Set Initial Compounding to “Daily”.
   3. Set Calculation Method to “Normal”.

4. Click on row one of the cash flow grid. Fig. 1
   1. Set the Series to “Deposit”.
   2. Set the Date to 11/24/2024  (mm/dd/yyyy).
   3. Set the Amount to $28,500.00.
   4. Set # Periods to 92.
   5. Set Frequency to “Daily”.
      • The date 92 days from the start date will be February 23, 2025.
      • This date is calculated automatically by the calculator.

5. Create a “Withdrawal” series in row two—we'll return to this in the next step. Fig. 2
   • Assume we are calculating accrued interest for a bond.
   • Bonds typically compound interest semiannually.
   1. Change Initial Compounding to “Semiannually”.
   2. Change # Periods in row one to 1.

6. Set the details of the “Withdrawal” series in row two:
   1. The Date should already be set to 02/24/2025.
      • Step 4 calculates the last of the 92 days as February 23, 2025. However, we need 92 full twenty-four-hour periods, which ends on February 24. Think of it this way: two days would be November 24 and November 25, but you cannot make a deposit on November 24 and withdraw it on November 25 and expect to earn two days of interest. To earn interest for two full days, the funds must be withdrawn on November 26. The same concept applies here.
   2. Set the Amount to “Unknown” by typing U.
   3. Set # Periods to 1. Fig. 3

• We are now ready to calculate the unknown value. Your screen should look like this:

7. Calculate:
   • Result: $28,880.73. Fig. 4
   • Click the Schedule button to view interest earned: $380.73

The return on an investment of $28,500.00 over 92 days at an interest rate of 5.3%, using semiannual compounding, is $380.73.

Back to the Ultimate Financial Calculator.