Pipe Size Tool | Water & Air Pipe Diameter Calculator
Proper pipe sizing is essential for the efficient operation of any fluid or gas distribution system. Our Pipe Diameter Calculator allows engineers and technicians to quickly determine the minimum required internal diameter and select the standard DN (Diamètre Nominal) size based on fluid flow rate and design velocity.
Pipe Diameter Sizing
How to Use the Pipe Size Calculator
- Enter Flow Rate: Input the volume of fluid or gas moving through the system and select your preferred unit (m³/h, l/min, or l/s).
- Select Fluid Type: Choose between Heating Water, Cold Water, Hot Water, or Compressed Air. This will automatically load the standard recommended design velocity.
- Adjust Design Velocity: If your project requires a specific velocity, you can manually override the preset value (e.g., keeping velocity under 1.2 m/s to prevent acoustic noise).
- Review Results: The calculator outputs the exact Minimum Inner Diameter (mm), the Recommended Standard DN Size, and the actual velocity the fluid will have within that standard pipe.
Pipe Sizing Formula
The calculation is based on the fundamental continuity equation for fluid dynamics:
D = √ (4 × Q) / (π × v)Where D is the inner diameter, Q is the volumetric flow rate (converted to m³/s), and v is the fluid velocity (m/s). The result is then converted to millimeters and matched against standard European EN/ISO steel pipe dimensions to find the closest safe DN size.
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