Pocket HVACLast updated October 30, 2026
By using this site, you agree to these terms.
Use the results as a check
The calculators are free reference tools for HVAC work. A result is only as good as the readings you put in, so a bad gauge, an uninsulated probe or a system that hasn't settled will give you a wrong answer.
Always check results against the equipment manufacturer's charging chart, installation instructions and data plate. Where they disagree with this site, follow the manufacturer.
Safety and the law
Only work on refrigerant systems if you're trained and certified to do it (in the US, that means EPA Section 608 certification). Follow the manufacturer's instructions, your local codes and safe work practices, especially with A2L refrigerants like R-454B and R-32.
Nothing on this site is engineering, legal or code advice. The duct tools size one duct run at a time and don't replace a full duct design.
No warranty
I work hard to keep the numbers right, but the site is provided as is, without any warranty. To the extent the law allows, I'm not liable for any loss, damage or injury that comes from using the site or relying on its results.
Using the site's content
You're welcome to link to any page and to share results with customers and coworkers. The site's text, design and code are mine, so please don't copy pages or tools to publish somewhere else.
The PT chart data is the exception. You can reuse the numbers in the PT charts, in print or online, under the Creative Commons Attribution 4.0 license (CC BY 4.0). Just credit Pocket HVAC and link back to the chart you used.
Links to other sites
Tool pages link to the sources they use. I don't control those sites and I'm not responsible for what's on them.
Changes
I may update these terms from time to time. The date at the top shows when they last changed, and using the site after a change means you accept the new terms.
If you have a question about these terms, email me at hello@pockethvac.com.