Do the math before you pull the wire.
Voltage drop, Ohm's law, conduit bends and six more calculators for the job site. Big numbers, works with no signal, and nothing to sign up for.
Coming soon
Free to use. Pro is $4.99, once.
Made for gloves, glare and basements.
Every screen is built around one big answer and buttons you can hit with a thumb.
Nine calculators, no code tables.
Every answer comes from the physics, with the formula shown under the result. Check it against your local code and the nameplate before you install.
| Calculator | What it works out |
|---|---|
| Free | |
| Ohm's Law | Enter any two of volts, amps, ohms and watts to get the other two. DC, single-phase and three-phase, with power factor. |
| Voltage Drop | Drop in volts and percent for copper or aluminium, AWG/kcmil or mm², and the longest run that stays under 3 %. |
| Conduit Bending | Offset spacing and shrink, 3-point saddles, kicks and back-to-back 90s, each with a diagram of your marks. |
| Resistors | 4- and 5-band colour codes, with the tolerance range. |
| Converter | HP and kW, feet and metres, °F and °C, torque, AWG and mm², kcmil and mm². |
| Pro | |
| Motor | Full-load current estimate from HP or kW, efficiency and power factor, plus synchronous speed and slip. |
| Transformer | Primary and secondary full-load amps, turns ratio and maximum fault current at the secondary. |
| Power Factor | kVAR needed to correct to your target power factor, drawn as a power triangle. |
| Wire Length | How long a run is, worked out from a resistance reading on the conductors. |
Built for the job, not the office.
Works with no signal
Everything runs on your phone. No account, no sign-in, nothing uploaded, so it works in a basement, a crawlspace or a new build with no Wi-Fi yet.
Readable in full sun
Sun mode gives you black on white with heavy outlines. The charcoal dark mode is easier on the eyes inside. Or let it follow your phone.
Keeps the job together
Save any result to a job, add notes and photos, and share the whole job as a PDF with your foreman or the customer.
Free to use. Pro is $4.99, once.
The free version covers the everyday calculators. Pro is a single purchase with no subscription and no ads, and it comes back with you when you change phones.
Pro adds
- Motor, Transformer, Power Factor and Wire Length
- Unlimited jobs (free keeps 3)
- Unlimited favourites (free keeps 4)
- Share jobs as PDF
- Full history (free shows today)
Questions
Does it work without a signal?
Yes. Every calculator, your jobs and your history live on your phone. Nothing needs the internet except buying or restoring Pro.
Is it based on the electrical code?
No. The app uses standard physics and maths formulas and shows them under each result. It doesn't include CEC or NEC tables, so always check your answer against your local code, the nameplate and manufacturer data.
Can I use metric?
Yes. Settings switches lengths to metres and centimetres, and wire sizes can be shown in mm². You can also pick US or Canadian spelling.
Does it work on iPad?
Yes, on iPhone and iPad with iOS 17 or later.
I bought Pro. How do I get it on a new phone?
Sign in with the same Apple ID and open the app. Pro usually comes back by itself. If it doesn't, tap Unlock Pro, then Restore purchase.
What does the app collect about me?
Nothing. There's no account, analytics or advertising. Read the privacy policy.