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How long does it take for an 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 some information about your air compressor first, and then plug the information into the formula shown.

• 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

### 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 air engineer to help you.

### If you have a question about how long it takes to Fill An Air Tank, feel free to post it here.

Maybe an engineering type will see this page and offer some help!