# Fill An Air Tank

How long does it take for your air compressor to fill an air tank?

I have been asked that question many times on this website, and since there appears to be a good deal of interest, I have added a page to this site dealing with how long it takes to fill an air tank.

### How long to fill an air tank? You need to         gather this information

• V = Tank size
• Final pressure (cut-out pressure)
• Initial pressure (cut-in pressure)
• 7.48 - conversion from gallons to CFM
• Atmospheric pressure = 14.7
• Compressor Pump Delivery in CFM

Then, you apply the information to the following formula:

### Example:

• My tank size = 100 gallons
• Cut-out pressure = 160 PSI
• Cut-in pressure = 80 PSI
• Conversion = 7.48
• Atmospheric pressure = 14.7
• Compressor Pump capacity = 4 CFM

That gives us:

Therefore:

100 x 80 = 8,000

Divided by:

440 (7.48 x 14.7 x 4 rounded up)

= 18.2 minutes

Folks, you are welcome to use these calculations yet be a bit cautious. While the information is sourced from a number of reputable locations I cannot be 100% sure of the accuracy, and therefore, you use this information at your own risk.

If you need to be 100% sure, get an engineer to help you.