Free calculator app · HVAC + Electrical
The pocket reference, reborn as an app.
Intry is the free calculator app for electricians and HVAC techs. Every code-accurate tool installs on your phone, saves your work to the job, and runs offline. No login, no ads, no app store.
On a computer? Open intrysys.com on your phone to add it.
The book had the numbers.
For decades the numbers lived in a book. Ugly's in your back pocket. The code book on the seat. A pressure-temperature chart taped inside the van. They worked. You still had to find the table, read it in bad light, and do the math by hand.
The notepad had your work.
The other half never made it into any book. The bends you marked. The superheat you read. The panel you sized. That lived on a notepad, a scrap of drywall, or your memory. It was gone by the next callback.
Gone by the next callbackIntry is both. On the phone in your hand.
Calculators that show the math and cite the source, plus a place that remembers what you figured out. Saved to the job. Working offline.
Do the math once. Keep it. Never figure it twice.
The calculators inside the app.
One free app, every field calculator. Each one shows the math and cites its source. Tap any to run it now; add Intry to your phone to keep them offline.
Questions techs ask.
What is the best free calculator app for electricians?
Intry is a free calculator app built for electricians and HVAC techs. Every tool is free with no login and no ads, it works offline once you add it to your home screen, and every electrical answer cites the exact NEC 2023 table and section so you can defend it. Unlike most store apps, it is not one calculator: conduit bending, voltage drop, wire size, conduit fill, box fill, EV charger, and load calc are all in one place.
What is the best free calculator app for HVAC techs?
Intry is a free calculator app for HVAC technicians and electricians. Superheat and subcooling (with R-454B and A2L support), BTU load, A2L line set sizing, charge limits, and EPA leak rate are all in one app, free, with no login and no ads. It works offline in a mechanical room with no signal, and the refrigerant numbers come from published manufacturer pressure-temperature data, not rounded rules of thumb.
Is Intry free?
Yes. Every calculator and the installable app are completely free, with no paywall, no subscription, and no ads. There is nothing to buy.
Do I need an account or a login?
No. Intry has no login, no email gate, and no signup. The jobs and readings you save live on your own device, not on our servers.
Does it work offline?
Yes. Once it is added to your home screen the calculators run without a signal, so they work in basements, mechanical rooms, and anywhere cell service drops.
Does it work on iPhone and Android?
Yes. On iPhone, open intrysys.com in Safari, tap Share, then Add to Home Screen. On Android, open it in Chrome and tap Install app or Add to Home screen.
How does an app help with conduit bending?
It does the layout math for you. Enter the offset height and angle and it returns the exact marks, the shrink, and the multiplier, plus 3- and 4-point saddles, stub-90s, and kicks, with the bend diagram. You still bend the pipe; the app kills the arithmetic and the guesswork.
Is it a real app or a website?
Both. Intry is a Progressive Web App. It runs in the browser, but when you add it to your home screen it installs and behaves like a native app, full screen and offline, with no app store download.
Why you can trust the number
The accuracy is the whole point.
Every electrical answer cites the exact NEC 2023 table and section. Pressure-temperature charts and bender profiles come from published manufacturer data. The math is always shown. No login, no email, no ads. Your saved jobs stay on your device.
Spot a wrong number? Email us. We fix it.