Enter the HHV value for the fuel (btu/ft^3) and the specific gravity of the fuel into the Wobbe Index Calculator. The calculator will evaluate the Wobbe Index.

## Wobbe Index Formula

The following two example problems outline the steps and information needed to calculate the Wobbe Index.

**WI = Vc / (Gs)^1/2**

Variables:

- WI is the Wobbe Index ( )
- Vc is the HHV value for the fuel (btu/ft^3)
- Gs is the specific gravity of the fuel

To calculate a Wobbe index, divide the HHV value for the fuel by the specific gravity of the fuel.

## How to Calculate Wobbe Index?

The following steps outline how to calculate the Wobbe Index.

- First, determine the HHV value for the fuel (btu/ft^3).
- Next, determine the specific gravity of the fuel.
- Next, gather the formula from above = WI = Vc / (Gs)^1/2.
- Finally, calculate the Wobbe Index.
- 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.

HHV value for the fuel (btu/ft^3) = 1050

specific gravity of the fuel = .61

WI = Vc / (Gs)^1/2** **= ?