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Pipe Size Calculator

Calculate the required internal pipe diameter for your heating system based on power, temperature difference, and target velocity.

Flow Rate
0.190
litres per second
Flow Rate
11.429
litres per minute
Internal Diameter
16.40
millimetres (mm)
LPS = KW / (SHC × ΔT)
LPM = LPS × 60
d = 2 × √(((1000 / 3.14) / v) × LPS)

Formula Reference

d = internal diameter (mm)
v = target velocity (m/s)
LPS = litres per second
LPM = litres per minute
KW = Kilowatts
SHC = Specific heat capacity (4.2)
ΔT = Delta T (°C)

Important: This calculator provides indicative pipe sizing guidance only. Always consult with a qualified heating engineer for your specific installation requirements.