A venturi meter is also called a venturi flowmeter. It is used to calculate the velocity of fluids in running through a pipeline. The fluid may be a liquid or a gas. The meter consists of a pipe with a narrowing throat that expands back to it's original diameter on the other side of the choke point. The venturi meter calculates velocity by measuring the pressure head at both points before and after the narrowed throat.

Venturi meters are used in pipelines at wastewater collection systems and treatment plants. They are used in wastewater pipes because their overall design structure allows for solids to pass through it instead of collecting in front of it. Less buildup in the pipes allows for more accurate readings of the pressure of the wastewater and thus its velocity.

The temperatures and pressures of chemicals in a pipeline do not affect the accuracy of a Venturi flowmeter and because of this they are used in crude oil pipelines. Crude oil pipelines, such as the ones in Alaska, are exposed to extreme temperatures during the long arctic winter months. Another advantage of using the Venturi meter in such volatile and frigid environments is that it has no moving parts; there is no risk of them freezing and breaking due to thermal expansion.

The venturi in carburetors is used to measure airflow in a car engine and to ensure that a correct amount of fuel is fed to the gas combustion engine when needed during driving. The air and fuel mixture must be evenly distributed to the engine in order for it to work properly. The temperatures of air and fuel are constantly changing due to the shift in temperatures that occur in an engine during idling, acceleration, high speeds, and low speeds. The venturi meter allows the carburetor to adjust and calibrate the distribution of fuel and air to the engine as needed.