**Here’s one of the most used formulas you should keep on hand… **

**How to find how many CFM your air compressor delivers.**

**Follow these steps to find how many
CFM Your Air Compressor delivers**

1. **STOP** the compressor unit

2. **CLOSE** the outlet valve on the tank/air receiver

3. **DRAIN** the condensate from air receiver until there is 0 PSIG -then **close the drain valve **

4. **NOTE THE TIME**– minute & second. Then START THE UNIT.

When unit stops/unloads – then NOTE THE TIME again – minute & seconds. Convert minutes into seconds and then total number of seconds it takes between START and STOP/UNLOAD.

5. NOTE the **GUAGE PSIG** reading

6. NOTE the Air Receiver/Tank **GALLON SIZE **

7. **USE THIS FORMULA:**

**TANK GALLONS x .538* x PSIG divided by SECONDS **

* *

**EXAMPLE:**

You have an **80** gallon tank, your total seconds timed were **189** and you noted **175** PSIG.

**80** multiplied by **.536** = 42.88

42.88 multiplied by **175** (example PSIG) = 7504.00

7504.00 divided by **189** (total seconds**)**= **39.71 CFM delivered**

You now know that your air compressor is delivering 39.71 CFM

*Your Response to this evaluation should be to compare this number with what your air compressor manufacturer says your CFM should be and evaluate how efficiently your compressor is running.*

Tommy McGuire

McGuire Air Compressors, Inc.

*“Real People with Real Compressor Experience”*

**1-888-229-9999**

**www.industrialaircompressors.biz**

**www.hosereels.biz**

**www.airdryers.biz**