Pneumatic Cylinder Air Consumption Calculator
Pneumatic cylinder air consumption per cycle (L ANR) from bore, stroke, pressure and tubing, plus L/min, required air flow and compressor size (SMC).
Formulas (SMC Data 2)
- Cylinder qc = A × L × (P + 0.1) ÷ 0.1 × 10⁻⁶ (L (ANR), A mm², stroke L mm, P MPa)
- Tubing qp = a × l × P ÷ 0.1 × 10⁻⁶ (a inside area mm², l length mm)
- Double acting q = qc1 + qp1 + qc2 + qp2, single acting (spring return) q = qc1 + qp1, (spring extend) q = qc2 + qp2
- Per minute = q × cycles per minute × cylinders (L/min (ANR))
- Required air Q = (qc + qp) × 60 ÷ t (t stroke time s; larger of extend and retract)
Double-acting cylinder, 100 mm stroke, one cycle (L (ANR), no tubing)
| Bore / rod (mm) | 0.4 MPa | 0.5 MPa | 0.6 MPa |
|---|---|---|---|
| ø20 / 8 | 0.289 | 0.347 | 0.405 |
| ø25 / 10 | 0.452 | 0.542 | 0.632 |
| ø32 / 12 | 0.748 | 0.897 | 1.05 |
| ø40 / 14 | 1.18 | 1.42 | 1.65 |
| ø50 / 20 | 1.81 | 2.17 | 2.53 |
| ø63 / 20 | 2.96 | 3.55 | 4.14 |
| ø80 / 25 | 4.78 | 5.74 | 6.69 |
| ø100 / 30 | 7.5 | 9 | 10.5 |
Air consumption is proportional to stroke — a 300 mm stroke uses three times these values; add tubing separately. Rod diameters are the first rows of SMC's Data 3 table.
Inside area of tubing and steel pipe (SMC table)
| Size | O.D. mm | I.D. mm | Inside area mm² |
|---|---|---|---|
| T0425 | 4 | 2.5 | 4.9 |
| T0604 | 6 | 4 | 12.6 |
| TU0805 | 8 | 5 | 19.6 |
| T0806 | 8 | 6 | 28.3 |
| 1/8B | — | 6.5 | 33.2 |
| T1075 | 10 | 7.5 | 44.2 |
| TU1208 | 12 | 8 | 50.3 |
| T1209 | 12 | 9 | 63.6 |
| 1/4B | — | 9.2 | 66.5 |
| TS1612 | 16 | 12 | 113 |
| 3/8B | — | 12.7 | 127 |
| T1613 | 16 | 13 | 133 |
| 1/2B | — | 16.1 | 204 |
| 3/4B | — | 21.6 | 366 |
| 1B | — | 27.6 | 598 |
SMC example (checked by tests to give the same values)
- Ten ø50 cylinders, 600 mm stroke, 0.5 MPa, 5 cycles per minute, with 2 m of 6 mm ID tube between cylinder and valve.
- Cylinder per cycle: 13 L (ANR) from SMC's graph — by formula, extend 7.07 + retract 5.94 = 13.0 L.
- Tubing per cycle: 0.56 L (ANR) — by formula, 28.3 mm² × 2000 mm × 0.5 ÷ 0.1 × 10⁻⁶ × 2 = 0.565 L.
- Total (13 + 0.56) × 10 × 5 = 678 L/min (ANR). Size the compressor with margin — SMC gives at least 1.4 times (about 950 L/min) as a reference.
How to read it
- In the cylinder formula, (P + 0.1) ÷ 0.1 turns gauge pressure into an absolute pressure ratio against atmosphere (about 0.1 MPa) — a volume filled at 0.5 MPa expands six times at atmospheric pressure.
- SMC's formula uses P ÷ 0.1 for tubing (P + 0.1 for the cylinder). It is reproduced as published.
- Use air consumption for compressor size and running cost, and required air flow (instantaneous flow) to size valves, filters, regulators and upstream piping.
- When choosing a compressor, allow for temperature drop, leakage and intermediate equipment, and pick a delivery well above the calculated total.
FAQ
What is the cylinder air consumption formula?
SMC's formula is qc = area (mm²) × stroke (mm) × (pressure MPa + 0.1) ÷ 0.1 × 10⁻⁶ L (ANR). For a double-acting cylinder, add extend, retract and the tubing.
What does ANR mean?
Air volume converted to standard atmospheric conditions — the volume compressed air takes when expanded to atmospheric pressure, so it compares directly with a compressor's delivery (free air).
How do I size a compressor?
Add up the per-minute air consumption (L/min ANR) of all cylinders and add margin. SMC gives at least 1.4 times as a reference, allowing for temperature drop, leakage and intermediate equipment.
Why include tubing length?
Each time the valve switches, the tubing between valve and cylinder is filled and exhausted too. With a small cylinder and long tubing, the tubing share becomes large.
For the force the same cylinder delivers, use the Pneumatic Cylinder Force Calculator. To convert pressure units, use the Pressure Unit Converter. For the steps through to compressor size, see the guide Pneumatic cylinder air consumption and compressor size.
Basis
Formulas and the tubing area table are from SMC's «Best Pneumatics» technical data «Technical Data 2: Air Consumption and Required Air Volume» (p.1574, equations (8)–(16)); the example and compressor margin (1.4 times) are from «Air Cylinders Model Selection» step 4 (p.1573) (PDF 6-2-1-m21-43-tech_en on SMC's official site). Tests check that this calculator reproduces those values. Rod diameters vary by series — use your cylinder's catalogue.