Enter the initial and final total dissolved solids into the calculator to determine the Osmotic Gap. This calculator can also evaluate any of the variables given the others are known.

## Osm Gap Formula

The following formula is used to calculate the Osm Gap.

OG = (TDSi - TDSf) / TDSi * 100

Variables:

- OG is the Osmotic Gap TDSi is the initial total dissolved solids TDSf is the final total dissolved solids

To calculate the Osmotic Gap, subtract the final total dissolved solids from the initial total dissolved solids. Then, divide the result by the initial total dissolved solids. Multiply the quotient by 100 to get the Osmotic Gap in percentage.

## How to Calculate Osm Gap?

The following steps outline how to calculate the Osmotic Gap (OG).

- First, determine the initial total dissolved solids (TDSi).
- Next, determine the final total dissolved solids (TDSf).
- Next, gather the formula from above = OG = (TDSi – TDSf) / TDSi * 100.
- Finally, calculate the Osmotic Gap.
- After inserting the variables and calculating the result, check your answer with the calculator above.

**Example Problem : **

Use the following variables as an example problem to test your knowledge.

Initial total dissolved solids (TDSi) = 150

Final total dissolved solids (TDSf) = 120