Airflow calculator
Make sense of airflow and static pressure.
Compare round and rectangular duct sizes for the job. Work out friction rate, check a size you already have, and use AI Chat when the readings raise another question.
Size ducts and keep the calculations with the job.
Keep airflow calculations in one place
Work with CFM, static pressure, and duct measurements in one app. Move between friction-rate calculations and duct sizing as the job needs.
Work out friction rate for the duct run
Use static-pressure readings, component pressure losses, and total effective length to work out the friction rate for your duct-sizing calculation.
Compare round and rectangular duct sizes
See sizing options for your CFM and friction rate. Enter a diameter or rectangular dimensions to check velocity and friction before choosing a size.
Pick up the job on your next visit
With Basic or Pro, save your airflow calculations and reopen them on mobile or web. Keep the figures from the last visit ready for your follow-up.
Frequently asked questions
Which airflow calculations are included?
Calculate available static pressure and friction rate, compare round and rectangular duct sizes, and check velocity and friction for a manual size. AI Chat is available when you want to talk through the readings.
Can I use the airflow tools on my computer?
Yes. Use airflow and duct-sizing tools in the web app, as well as on iPhone, iPad, and Android. Basic and Pro let you save calculations and reopen them with the same account.