Electric blue / cyan
Electrical tools and references.
Planning aids and reference-style tools for electrical-related residential project work where appropriate.
Hub Structure
Calculators
Working calculators for quick planning.
Enter the measurements you have, keep units consistent, and use the formula notes to understand how each result is estimated.
Electrical
Demand / Service Load Calculator
Estimate a planning service load from floor area, required small-appliance/laundry circuits, fixed appliance loads, and voltage.
Results
Enter the required measurements to calculate results.
General lighting = area x 3 VA. Small-appliance and laundry circuits = 1,500 VA each. Demand = first 10,000 VA at 100% plus remainder at 40%, then add largest HVAC load. Amps = demand VA / volts.
Help
- Planning aid only; final service sizing must follow the locally adopted electrical code.
- Fixed appliance and HVAC loads should come from nameplates or verified documentation.
Electrical
Voltage Drop Calculator
Estimate branch-circuit voltage drop by conductor material, gauge, current, voltage, and one-way distance.
Results
Enter the required measurements to calculate results.
Single-phase drop = 2 x K x amps x feet / circular mils. Three-phase drop = 1.732 x K x amps x feet / circular mils. Copper K=12.9, aluminum K=21.2.
Help
- Uses common conductor constants at typical operating temperature; field conditions can vary.
Electrical
Wire Ampacity Reference
Reference common 75C conductor ampacity by material and wire size.
Results
Reference ampacity
130 A
75C column reference before code adjustments.
Looks up common 75C conductor ampacity by AWG and material.
Help
- Reference only; actual allowable ampacity depends on insulation rating, terminal temperature, conductor count, ambient conditions, and code rules.
- Small conductor rules may limit breaker sizing below the listed ampacity.
Electrical
Conduit Fill Calculator
Estimate conduit fill percentage for same-size THHN/THWN conductors.
Results
Enter the required measurements to calculate results.
Fill percent = total conductor area / allowed conduit area. More than two conductors are compared to 40% fill.
Help
- Uses approximate trade-size areas for common EMT and Schedule 40 PVC; verify against local code tables.
Electrical
Box Fill Calculator
Estimate required electrical box volume from conductors, devices, clamps, grounds, and conductor size.
Results
Enter the required measurements to calculate results.
Box-fill units = conductors + grounds as 1 unit + internal clamps as 1 unit + device yokes as 2 units each. Volume = units x conductor volume allowance.
Help
- Planning aid based on common NEC box-fill counting concepts; verify the exact installation.
Electrical
Watts / Volts / Amps Conversion
Convert between watts, volts, and amps when two values are known.
Results
Enter the required measurements to calculate results.
Watts = volts x amps. Amps = watts / volts. Volts = watts / amps.
Help
- For simple single-phase resistive or nameplate calculations; power factor is not included.
Quick References
Practical reference slots.
This area is ready for formulas, terminology, measurement notes, unit conversions, and checklists as each tool is verified.
Before You Calculate
Start with clear measurements.
Gather fixture, appliance, or equipment details.
Note approximate distances, locations, and project constraints.
Confirm when professional review or permitted work is required.