Free Calculators for Tradesmen
Quick, accurate on-site calculators. No app to install. Referenced to the standards you actually work to — BS 7671 for electrical and Gas Safe technical bulletins for gas.
Gas
Gas Rate Calculator
Convert meter readings to m³/hr and kW for natural gas or LPG.
Electrical
Zs Calculator (Ze + R1+R2)
Compute earth fault loop impedance from Ze and R1+R2.
Electrical
Prospective Fault Current (Ipf)
Calculate prospective fault current from voltage and Zs.
Electrical
RCD Trip Time Check
Verify measured RCD trip times pass BS EN 61008 limits.
Electrical
Voltage Drop Calculator
Calculate cable voltage drop for T&E single-phase circuits.
Gas
Flue-Gas Ratio Checker
Get the CO/CO₂ combustion ratio and its BS 7967 action band.
GasBeta
Gas Pipe Sizing Calculator
Size a whole installation against BS 6891:2015, section by section.
RefrigerationBeta
F-Gas Leak Check Calculator
Turn a refrigerant charge into tonnes CO₂e and the leak-check interval you owe.
GasBeta
Installation Volume Calculator
Work out installation volume the Edition 4 way — pipework, meter and fittings.
GasBeta
Tightness Test Calculator
Get the maximum permissible pressure drop from your installation volume.
Reference
UK Refrigerant Reference
GWP, safety class and UK F-Gas status for every common refrigerant.
Tool
Refrigerant Replacement Finder
The compliant lower-GWP swap for R-410A, R-404A, R-22 and more — with the GWP drop.
Reference
UK F-Gas Phase-Down Timeline
The ban dates that decide what you can fit and service — and where GB diverges from the EU.
More calculators coming. Browse certificates while you're here.