# How to Convert Lb/H to GPM

by Matthew Weeks
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The mass flow rate of a system is a measurement of how much mass of a given material passes through a defined plane of space in a given time period. It is typically expressed in units like pounds per hour. Mass flow is related to volumetric flow, which is a measurement of the volume of a material that passes through a plane. It is usually expressed in units like gallons per minute. If you have a measurement of the specific gravity of the material in question, it is possible to convert the former to the latter.

#### Step 1

Calculate the specific gravity of the material you are measuring, if you do not have it already. Specific gravity of a liquid is a measure of the ratio of the mass of a given volume of your material to the mass of an equivalent volume of water. Both measurements can be made with a mass scale.

#### Step 2

Multiply the specific gravity by 500.

Divide your pounds per hour measurement by the result calculated in Step 2 to find the equivalent measurement of gallons per minute.

• Calculator
• Mass scale