Enter the accumulated amount, interest rate per period, and the number of periods to determine the principal.

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## Reverese Interest Formula

The following formula is used to calculate the principal amount given the interest rate and accumulated amount.

P = A / (1 + r) ^n

- Where P is the principal amount ($)
- A is the accumulated amount ($)
- r is the interest rate per period(decimal)
- n is the number of periods

## Reverse Interest Definition

A reverse interest is a process of calculating a principal amount on an investment or loan given the accumulated amount, interest rate per period, and a number of periods.

## Example Problem

**How to calculate a reverse interest? **

First, determine the accumulated amount. For this problem, over a term of 5 years, the accumulated amount is found to be $400,000.00.

Next, determine the interest rate per period. This is found to be 5% per year. This will be converted to a decimal of .05 for calculations.

Next, determine the total number of periods. As mentioned above, this is a time period of 5 years.

Finally, calculate the principal amount using the reverse interest formula.

P = A / (1 + r) ^n

= 400,000/ (1+.05)^5

= $313,410.47