Free tools for HVAC technicians. No sign-up. Works on your phone.
Free HVAC Calculators
AC Tonnage Calculator
Find the right AC size for any room, with a Gulf-climate adjustment for hot regions like the UAE.
HVAC Unit Converter
Convert instantly between BTU, Ton, kW, PSI, Bar and CFM using standard ASHRAE definitions.
Electricity Cost Calculator
Estimate any appliance’s daily, monthly and annual running cost from its wattage and your local rate.
Motor, Belt, Pulley & Bearing Calculator
Get belt length, pulley ratio, fan RPM and bearing size in seconds.
Superheat & Subcooling Calculator
Check refrigerant charge instantly, with correct dew-point/bubble-point handling for glide refrigerants like R-407C.
AC Capacitor Calculator
Test any run capacitor under load and get an instant weak, failing or good verdict with recommended MFD.
AC Duct Size Calculator
Get round and rectangular duct size from CFM, plus air velocity and pressure loss, in imperial or metric.
Why Learn HVAC Pro
Learn HVAC Pro is a set of free, no-signup calculators built by Irfan Khan, an HVAC Supervisor with 10 years of hands-on field experience in Dubai and Sharjah, UAE. Every formula here is checked against real job-site numbers and standard engineering references (ASHRAE, ISO, NIST) — not generic textbook copy-paste. Pick a tool above to get an instant result, right in your browser.
Most HVAC calculators online are generic and built for the US market. Working AHU, chiller and split-AC systems in Gulf heat all day means seeing where those generic numbers fall short. Learn HVAC Pro’s tools add real Gulf-region adjustments where they matter, explain the formula behind every result, and link to the official standard the formula comes from — so you’re never just trusting a black-box number.
Want to know more about who built these tools? Visit the About Learn HVAC Pro page for the full story and 10 years of real Gulf-region HVAC field experience behind this site. You can also practise with the HVAC interview questions.