Enter the quantity of the first isotope and the quantity of the reference isotope into the Isotope Ratio Calculator. The calculator will evaluate and display the Isotope Ratio.

## Isotope Ratio Formula

The following formula is used to calculate the Isotope Ratio.

**ISR = I / RI **

- Where ISR is the Isotope Ratio
- I is the quantity of the first isotope
- RI is the quantity of the reference isotope

## How to Calculate Isotope Ratio?

The following example problems outline how to calculate Isotope Ratio.

Example Problem #1:

- First, determine the quantity of the first isotope.
- The quantity of the first isotope is given as: 6.

- Next, determine the quantity of the reference isotope.
- The quantity of the reference isotope is provided as: 2.

- Finally, calculate the Isotope Ratio using the equation above:

ISR = I / RI

The values given above are inserted into the equation below and the solution is calculated:

ISR = 6 / 2 = 3:1

Example Problem #2:** **

For this problem, the variables required are provided below:

quantity of the first isotope = 7

quantity of the reference isotope = 4

Test your knowledge using the equation and check your answer with the calculator above.

ISR = I / RI ** = ?**