Electrician Calculator ProCalc

Electrician ProCalc is an electrician calculator for electricians, apprentices and contractors: voltage drop, wire and cable size, conduit fill, box fill, breaker size, kW to amps and Ohm's law in one electrical calculator. Every result shows the formula, the numbers substituted into it, the assumptions and any warnings.

METRIC OR IMPERIAL, MM² OR AWG
Choose Metric or Imperial once. Metric opens the calculators in meters and mm² (1.5–300 mm²) with IEC 60364-5-52 data and IEC breaker ratings. Imperial opens them in feet, inches and AWG/kcmil (14 AWG–500 kcmil) with NEC tables for ampacity, conductor resistance, breaker ratings and motor full-load current. Any field can still switch its unit, and numbers take a decimal comma or point.

WIRE SIZE AND VOLTAGE DROP CALCULATOR
• Voltage drop – DC, single-phase and three-phase runs with resistance and reactance, checked against your limit in %
• Max cable length – the longest run within your limit
• Copper vs aluminum – the same run with both materials
• Derating helper – minimum table ampacity from temperature and bundling factors
• Wire size estimator (Pro) – a wire size calculator: standard conductor and protective rating from current, continuous load, distance, material, drop limit, derating and, for mm², installation method A1 to E
• Voltage drop comparison (Pro) and Scenario comparison (Pro) – conductor sizes or two cable runs side by side

POWER, CURRENT AND OHM'S LAW
• Ohm's law, Power calculator, Current calculator, Resistance calculator, Voltage calculator
• Single-phase power, Three-phase power, Power factor, kVA calculator
• kW to amps, Amps to kW, Horsepower to amps
• Motor load helper – running and starting current

CONDUIT FILL, BOX FILL AND BREAKER SIZE
• Conduit fill – EMT and PVC Schedule 40 from 1/2 to 2 in, metric PVC 20–40 mm or your own diameter
• Box fill – box volume in cm³ or in³ with NEC 314.16(B) allowances
• Breaker / fuse helper and Fuse size helper – the next standard rating, with a continuous-load setting

ENERGY AND CONVERSIONS
• Energy cost, Generator sizing, Load schedule (Pro) with demand factor and margin
• AWG to mm² – 14 AWG to 4/0 in square millimeters

PROJECTS, HISTORY AND REPORTS
Save any electrician calculator result to History, star the tools you use most in Favorites and group each job in Projects with notes and a summary. Templates: Blank project, Panel check, Cable run, Small shop estimate. A project can also be imported from a CSV report. The Reference tab holds 10 short articles, from Common formulas to IP ratings.

WITHOUT PRO AND WITH PRO
Without Pro the electrician calculator gives you 24 of the 28 calculators, the last 10 history items, up to 3 favorites, 1 local project with up to 10 calculations, copy result text and every Reference article.
Pro adds the 4 calculators marked (Pro), unlimited history, favorites and projects, project reports, PDF, CSV and text export, and saved input presets. Choose Pro Lifetime (one-time purchase) or Pro Monthly (subscription); Restore purchases is in the app.

WHERE YOUR DATA IS STORED
Calculations run on your device, so the electrical calculator also works without a mobile signal on site. Calculations, history, favorites and projects are stored in the app on your device; Settings has Delete all local data. Buying or restoring Pro goes through Google Play and needs an internet connection.

MORE
Light, dark or system theme, interface and PDF reports in 12 languages, side navigation on tablets, and default voltage, power factor, wire size and margin in Settings.

IMPORTANT
Results are estimates based on the inputs and assumptions shown; this electrical calculator does not certify code compliance. Verify final work against local codes, manufacturer data and professional requirements.

Recent changes:
• Voltage drop is more accurate: conductor resistance and reactance come from NEC and IEC tables and include power factor
• Metric or Imperial now sets the units, wire sizes (1.5–300 mm² or 14 AWG–500 kcmil) and breaker ratings the calculators open with
• Motor current from the NEC full-load current tables in Imperial
• Inputs accept a decimal comma
• PDF reports print Cyrillic and accented letters
• Buying and restoring Pro is more reliable
• Better screen reader and large text support