HVAC, Plumbing & Electrical
BTU, CFM, pipe flow, wire sizing, voltage drop, and circuit calculators for trades and home installers.
Tank Volume Calculator: Capacity, Fill Level & Hydrostatic Pressure
Rolling Offset Calculator: Formulas, Multipliers & Cut Lengths
Pipe Internal Volume Calculator: Fluid Capacity, Weight & Flow
Junction Box Size Calculator — NEC 314.16 Box Fill & Volume Guide
Liters per Minute (LPM) Calculator: Flow Rate, Pipe Sizing & Capacity
Building Heat Loss Calculator: HVAC Design Load & Boiler Sizing
Gas Furnace Sizing Calculator: BTU Load & AFUE Efficiency Guide
GPM Calculator: Flow Rate Formulas for HVAC & Plumbing
Gallons per Square Foot Calculator: Convert Rainfall Depth to Collected Volume
Fire Flow Calculator — ISO & NFA Methods for Water Supply Sizing
French Drain Calculator: Sizing, Hydrology & Material Estimates
CFM Airflow Calculator — Size Ventilation, Ductwork & HVAC Loads with Precision
Electrical Box Fill Calculator — NEC 314.16 Volume Requirements & Conductor Allowances
Heating Boiler Power Calculator via Volumetric Heat Loss Method
Air Conditioner Room Size Calculator — BTU Cooling Load Estimator for Any Room