Calculate compressed air consumption of a pneumatic cylinder in L/min and cfm from bore, stroke, pressure and cycle rate, or the cycles your flow supports.

Blank ignores the rod, which slightly overstates return-stroke air.

6 bar (≈ 87 psi) is typical shop air. Use your regulator setting.

Cylinder count and reserve
Blank means one cylinder.

Blank means no added reserve; choose a margin for your equipment.

Air Usage Formula

The air usage calculation is based on flow rate multiplied by operating time. The calculator converts the entered units to base units first, using cubic feet per minute for flow rate, minutes for time, and cubic feet for total air usage.

AU = Q × t
Q = AU / t
t = AU / Q
  • AU = total air usage, usually in cubic feet, cubic meters, or liters
  • Q = flow rate, usually in cfm, m³/min, or L/s
  • t = operating time, usually in minutes or hours

Select Total air volume, Flow rate, or Operating time, then enter the other two quantities. Flow and volume must use the same pressure and temperature reference. The cylinder modes instead estimate free-air flow or cycle rate from bore, rod diameter, stroke, gauge pressure and cylinder count. They assume equal gas temperature and 101.325 kPa reference pressure; piping dead volume, pressure losses and equipment limits are excluded.

Air Flow and Volume Unit Conversions

These conversions are commonly used when comparing air flow rates and total air volume.

Flow rate unit Equivalent Use in calculation
1 cfm 1 cubic foot per minute Base flow rate unit
1 m³/min 35.3147 cfm Metric flow converted to cfm
1 L/s 2.11888 cfm Liter-per-second flow converted to cfm

Volume unit Equivalent Use in calculation
1 cubic foot 1 cf Base air usage unit
1 cubic meter 35.3147 cf Metric volume converted to cubic feet
1 liter 0.0353147 cf Liter volume converted to cubic feet

Examples

Example 1: Calculate total air usage

You have a tool that uses 12 cfm and it runs for 30 minutes.

AU = 12 × 30 = 360 cf

The total air usage is 360 cubic feet.

Example 2: Calculate operating time

You have 900 cubic feet of air usage and a flow rate of 15 cfm.

t = 900 / 15 = 60 minutes

The operating time is 60 minutes, or 1 hour.

FAQs

What does air usage mean?

Air usage is the total volume of air consumed over a period of time. For example, a device using 10 cfm for 20 minutes uses 200 cubic feet of air.

What is the difference between cfm and cubic feet?

cfm is a flow rate. It means cubic feet per minute. Cubic feet is a total volume. Flow rate tells you how fast air is being used, while total volume tells you how much air was used overall.

Why does operating time need to match the flow rate unit?

Flow rate includes a time unit. A rate in cfm means cubic feet per minute, so the time must be in minutes before multiplying. If you enter hours, the calculator converts hours to minutes before applying the formula.