Air Compressor Altitude and Temperature Derating Calculator
Hot or high site? Find out how much airflow you really get and what rated CFM to buy.
How derating works
A compressor moves a fixed volume of air. At altitude or in heat the air is thinner, so each cubic metre holds less oxygen and less usable air mass, and your tools get less. This calculator compares your site to a standard reference (sea level, 20 °C) using the standard atmosphere and the ideal gas law.
Example: at 1,000 m and 35 °C the air is about 84% as dense as standard, so a 176 CFM compressor delivers about 148.51 CFM of usable air.
Frequently asked questions
Does altitude reduce air compressor output?
Yes. Thinner air means less usable air delivered. Output falls roughly in line with air density, and engine power drops too.
How hot is too hot for a portable air compressor?
It depends on the model. The Brüder SP5000 is rated from -10 °C to 47 °C ambient. Check the rated range for your compressor.
How much CFM do I lose at 1,000 metres?
Roughly 11 percent at 20 °C. Heat adds to the loss. Enter your altitude and temperature above for your site.
Do I need a bigger compressor in hot Australian conditions?
Often yes. Size on the derated airflow. Enter the CFM your tools need and the calculator shows the rated CFM to buy.
Need the right portable air compressor? Brüder Australia is Australian-owned, with local stock, parts and service backing every machine.
JOIN THE BRÜDER LIST
Early access to new products, special deals, and practical advice from the field.
