// 17 Calculators · Free Tier

Electrical Calculators

Every calculation you run on a job, in fractional inches, working offline. Free tier includes all of them, no card required.

Each one below that has a written guide links to it. The guides show the arithmetic worked end to end, state the assumptions behind every table, and point out where one calculation interacts with another. Ampacity, voltage drop and fill are three separate checks, and passing one tells you nothing about the other two.

Voltage Drop
Drop across any run, single or three-phase.
Read the guide →
Box Fill
Cubic inches required under 314.16.
Read the guide →
Conduit Fill
How many conductors fit in a raceway.
Read the guide →
Wire Ampacity
310.16 across all temperature columns.
Read the guide →
Breaker Sizing
Branch, feeder and motor overcurrent.
Read the guide →
Load Calculation
Dwelling unit service sizing, Article 220.
Read the guide →
Conduit Bending
Offsets, saddles, kicks and stubs.
Read the guide →
3-Phase Power
kVA, kW, amps and power factor.
Read the guide →
Transformer
kVA to primary and secondary current.
Read the guide →
Grounding (GEC/EGC)
250.66 and 250.122 sizing.
Read the guide →
Wire Torque Specs
Terminal torque under 110.14(D).
Read the guide →
Ohm's Law
Volts, amps, ohms and watts.
In the app
Conduit Sizing & OD
Outside diameters and trade sizes.
In the app
Motor Data (FLC/LRA)
Full-load and locked-rotor current.
In the app
Bolt Torque Specs
Structural and equipment fasteners.
In the app
Support Spacing
Raceway and cable support intervals.
In the app
Cat 6 Wiring
T568A and T568B pinouts.
In the app
EVERY CALCULATOR, FREE

No card, no trial timer. The free tier includes all 17 calculators and the full reference library.

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Frequently asked questions

Are the calculators free?
Yes. Every calculator and the full reference library are on the free tier, with no card required. The paid tiers buy more AI code assistant scans per day, not more calculators.
Do the calculators work offline?
Yes. Basements, mechanical rooms and rural service calls all kill your signal, so the calculators and reference tables work without a connection.
Do they use fractional inches?
Yes. Bending and conduit inputs take sixteenths, because that is what a tape measure reads. Decimal-only input is the fastest way to spot a calculator built by someone who has never held a bender.
Can I use these instead of the code book?
No. These are calculation and navigation tools. When there is money or a failed inspection on the line, the adopted code text and your AHJ are the authorities.
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// DisclaimerThe National Electrical Code® (NEC®) and NFPA 70® are registered trademarks and copyrighted publications of the National Fire Protection Association (NFPA). This article is an independent educational resource and is not affiliated with, endorsed by, or sponsored by the NFPA. All code references in this article are paraphrased for educational purposes only and do not reproduce the official text of any NEC edition. This content is not a substitute for the official NFPA 70 publication. Electricians, contractors, and students are encouraged to purchase the official National Electrical Code from the NFPA at nfpa.org for complete and authoritative code text. Always verify requirements with the code edition adopted by your jurisdiction and your Authority Having Jurisdiction (AHJ).