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

To calculate the isotope ratio, divide the quantity of the first isotope by the quantity of the reference isotope.

## How to Calculate Isotope Ratio?

The following example problems outline how to calculate Isotope Ratio.

Example Problem #1:

1. First, determine the quantity of the first isotope.
• The quantity of the first isotope is given as: 6.
2. Next, determine the quantity of the reference isotope.
• The quantity of the reference isotope is provided as: 2.
3. 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