Mass flow rate, also known simply as mass flow, is a measurement that quantifies the mass of a substance (usually a fluid, such as a liquid or gas) that passes through a specific point in a pipeline, conduit, or system per unit of time. It is typically expressed in units like kilograms per second (kg/s), pounds per minute (lb/min), grams per second (g/s), or other similar units, depending on regional or industry-specific standards.

The formula for calculating mass flow rate is straightforward:

Mass Flow Rate (ṁ) = Density (ρ) × Volume Flow Rate (Q)

Where:

ṁ is the mass flow rate (e.g., kg/s, lb/min, g/s).

ρ is the density of the substance (typically in units like kg/m³, lb/ft³).

Q is the volume flow rate (e.g., m³/s, CFM, GPM), which is the rate of flow of the substance in terms of volume.

In this formula, the density (ρ) represents the mass of the substance per unit volume. The volume flow rate (Q) is the rate at which the substance flows through a specific cross-sectional area, and it is typically measured in cubic meters per second (m³/s) or other volume-based units.