BuildWire Calc: Voltage Drop

Voltage drop, wire size, breaker sizing, EV charger circuits, conduit bending, Ohm's law and more: 47 electrical, construction and HVAC calculators that all run offline. No account, no ads, no signal needed.

BuildWire Calc is an offline calculator app for electricians, builders and HVAC technicians. It has 47 field calculators in one place: voltage drop, wire size, concrete, roof pitch, rafters, BTU and more. No signal needed, no account, no ads.

FREE CALCULATORS Voltage drop calculator, Ohm's law, watts to amps, concrete slab, roof pitch, board feet, BTU calculator, CFM calculator and BTU to kW. No time limit.

ELECTRICAL CALCULATORS (22) Voltage drop and wire size for single phase, three phase and DC. Wire size for EV chargers, subpanels, hot tubs, solar PV, welders and generator interlock cables. Breaker size, motor circuit breaker, service load, equipment and electrode grounding conductors, ambient temperature correction, aluminum to copper wire size, three phase power, conduit bending marks, AWG to mm2, transformer and generator sizing.

CONSTRUCTION CALCULATORS (15) A concrete calculator for slabs, footings, steps and block walls, plus rebar and gravel. Roof pitch and rafter length, retaining wall blocks, board feet, stud spacing, shingle bundles, drywall screws, stair railing and stair stringer.

HVAC CALCULATORS (10) BTU for cooling and heating, AC size, CFM, duct size, furnace and heat pump size, superheat and subcooling, dew point, BTU to kW and a refrigerant PT chart.

TRY PRO WITH YOUR OWN NUMBERS Every locked calculator shows a worked example. Each month you also get 3 results with your own numbers on any Pro calculator.

WHY CREWS KEEP IT ON THE HOME SCREEN - Fast: results update as you type, with the calculation steps and warnings shown underneath. - Jobs: save any result to a job for a customer, quote or site, and see every number for that job in one list. - Reports: share a job as a PDF or CSV, or copy it as text, using the Android share sheet. - 14 languages. Feet and inches or metric, light or dark theme, favourites and history. - Private: no account, no ads, no analytics. Jobs and history are stored only on your phone.

PRO Pro unlocks all 47 calculators and job export as a PDF or CSV. Buy it once, or subscribe yearly and cancel any time in Google Play. Restore purchases from Settings.

GOOD TO KNOW Results are estimates for planning. Check them against your local electrical or building code, the manufacturer's data and the drawings before you cut, pour or wire. Copyrighted code tables are not included.

Need a calculator that is missing? Email support@buildwirecalc.com or see https://buildwirecalc.com/support/ . Privacy policy: https://buildwirecalc.com/privacy/