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Calculator Collection

HVAC Duct Sizing Calculator vs Pipe Sizing Calculator

Two calculators for the same neighbourhood of questions. Here is what each measures, what you feed in, and where you'd reach for one over the other.

Engineering

HVAC Duct Sizing Calculator

Calculate the required diameter or dimensions of HVAC ducts based on air flow rate and design velocity. Use this when designing ventilation systems to balance air delivery with noise and pressure loss constraints.

Answers
Duct Dimension (inches)
Inputs
Air Flow Rate, Design Air Velocity, Duct Shape, Aspect Ratio (for rectangular)
Fluid Mechanics

Pipe Sizing Calculator

Find the minimum required pipe diameter to keep fluid velocity within safe limits for a given flow rate. Use this when selecting pipe sizes for new installations or checking whether existing pipes can handle increased flow.

Answers
Minimum Pipe Diameter (mm)
Inputs
Flow Rate, Maximum Velocity, Safety Factor

At a glance

HVAC Duct Sizing CalculatorPipe Sizing Calculator
CategoryEngineeringFluid Mechanics
AnswersDuct DimensionMinimum Pipe Diameter
Inputs43
Result unitinchesmm

When to use each

Calculate the required diameter or dimensions of HVAC ducts based on air flow rate and design velocity. Use this when designing ventilation systems to balance air delivery with noise and pressure loss constraints.

Find the minimum required pipe diameter to keep fluid velocity within safe limits for a given flow rate. Use this when selecting pipe sizes for new installations or checking whether existing pipes can handle increased flow.

Compare page seeded from editorial siblings — both calculators list each other as related.