Pipe Diameter Calculator is designed for simple and quick calculation of pipe and duct dimensions based on a known flow rate and desired fluid velocity.

Calculate the required internal diameter of a round pipe or the required height of a rectangular duct for a given volume or mass flow rate and desired flow velocity.

The calculator can also determine flow velocity when the pipe or duct dimensions and flow rate are known.

Both volume flow and mass flow inputs are supported. For mass flow calculations fluid density can be entered directly. Gas density can also be calculated from absolute pressure temperature and specific gas constant using the ideal gas equation.

Features include:
• Pipe diameter calculation
• Flow velocity calculation
• Round pipes and rectangular ducts
• Volume flow and mass flow input
• Liquid and gas calculations
• Ideal gas density calculation
• Metric and Imperial units
• Fast and easy engineering calculation