All charts & calculators
Every reference on the site, grouped by what you're holding in your hand. All free, all formula-derived, all with the method shown.
Calculators
- Voltage Drop CalculatorPercent drop, end voltage and minimum conductor for any run length.
- Conduit Fill CalculatorFill percentage and maximum conductor count for EMT, RMC, IMC and PVC.
- Breaker Size CalculatorOvercurrent device rating and minimum conductor from load current.
- Wire Ampacity CalculatorDerated ampacity for ambient temperature and bundled conductors.
- Box Fill CalculatorVolume allowances for conductors, clamps, devices and grounds per NEC 314.16.
Wire & Conduit Charts
- Ampacity ChartEstimated allowable ampacity by conductor size, material and insulation rating.
- Wire Gauge ChartAWG diameter, circular mils, resistance and amp capacity in one table.
- Wire Size ChartWhat size wire for each breaker rating and typical circuit.
- Conduit Fill ChartMaximum THHN conductors per trade size for every raceway type.
Trade Size Charts
- Sheet Metal Gauge ChartGauge to thickness in inches and millimetres for steel, galvanised and aluminium.
- Rebar Size ChartBar designation, diameter, area and weight per foot.
- Socket Size ChartSAE to metric socket conversion with the closest interchangeable size.
- Pipe Thread ChartNPT nominal size, outside diameter, threads per inch and tap drill.
- Nut Size ChartBolt size to hex nut across-flats wrench size, SAE and metric.
- Allen Wrench Size ChartHex key sizes with SAE and metric cross-reference.