How to use this calculator
- Enter bore and rod diameter. Use the piston bore and rod diameter. Pick a standard bore when possible.
- Enter pressure. Enter the working pressure the cylinder sees at the port.
- Choose push or pull. Push uses full piston area; pull uses annulus area after subtracting rod area.
- Add flow for speed. Enter oil flow to calculate extension or retraction speed.
How it works
A hydraulic cylinder turns oil pressure into linear force. On extend, pressure acts
on the full piston area:
F_push = P · (pi/4) · B²
On retract, the rod removes area:
F_pull = P · ((pi/4) · B² - (pi/4) · d²)
where B is bore and d is rod diameter.
Stroke speed comes from the same working area: v = Q / A Smaller annulus area means a double-acting cylinder usually retracts faster than it extends for the same pump flow.
Worked example
Verified against the live calculator
A 50 mm bore, 22 mm rod cylinder at 160 bar has piston area about
19.6 cm². Push force is about 31.4 kN. On retract,
pressure acts on the 15.8 cm² annulus, so pull force is about
25.3 kN. At 20 L/min, extension speed is about
170 mm/s.
Reference data
Standard metric cylinder bore and rod combinations, with areas and force per 100 bar. Multiply the force columns by your pressure divided by 100 bar.
| Bore (mm) | Rod (mm) | Series | Piston area (cm²) | Annulus area (cm²) | Push @100 bar (kN) | Pull @100 bar (kN) |
|---|---|---|---|---|---|---|
| 25 | 12 | MM1 | 4.91 | 3.78 | 4.91 | 3.78 |
| 25 | 18 | MM2 | 4.91 | 2.36 | 4.91 | 2.36 |
| 32 | 14 | MM1 | 8.04 | 6.5 | 8.04 | 6.5 |
| 32 | 22 | MM2 | 8.04 | 4.24 | 8.04 | 4.24 |
| 40 | 18 | MM1 | 12.6 | 10 | 12.6 | 10 |
| 40 | 28 | MM2 | 12.6 | 6.41 | 12.6 | 6.41 |
| 50 | 22 | MM1 | 19.6 | 15.8 | 19.6 | 15.8 |
| 50 | 36 | MM2 | 19.6 | 9.46 | 19.6 | 9.46 |
| 63 | 28 | MM1 | 31.2 | 25 | 31.2 | 25 |
| 63 | 45 | MM2 | 31.2 | 15.3 | 31.2 | 15.3 |
| 80 | 36 | MM1 | 50.3 | 40.1 | 50.3 | 40.1 |
| 80 | 56 | MM2 | 50.3 | 25.6 | 50.3 | 25.6 |
| 100 | 45 | MM1 | 78.5 | 62.6 | 78.5 | 62.6 |
| 100 | 70 | MM2 | 78.5 | 40.1 | 78.5 | 40.1 |
| 125 | 56 | MM1 | 123 | 98.1 | 123 | 98.1 |
| 125 | 90 | MM2 | 123 | 59.1 | 123 | 59.1 |
| 160 | 70 | MM1 | 201 | 163 | 201 | 163 |
| 160 | 110 | MM2 | 201 | 106 | 201 | 106 |
| 200 | 90 | MM1 | 314 | 251 | 314 | 251 |
| 200 | 140 | MM2 | 314 | 160 | 314 | 160 |
Source: ISO 6020-2 mounting & rod-diameter series. Verify against the cylinder manufacturer's catalogue for the exact model.
Frequently asked questions
What does a hydraulic cylinder calculator size?
This page calculates the theoretical push force, pull force, piston area, rod area, annulus area and stroke speed from bore, rod diameter, pressure and flow.
How do I calculate hydraulic cylinder force?
Use force = pressure × area. Extend force uses the full bore area, A = pi·B²/4. Retract force subtracts the rod area from the bore area.
How do I calculate cylinder speed?
Cylinder speed is flow divided by working area. With the same flow, retract speed is usually faster because the annulus area is smaller than the piston area.
Should I enter pump pressure or relief pressure?
Enter the actual working pressure at the cylinder. A pump rating or relief setting may be higher than the pressure available under the load.
Does this include seal friction?
No. These are theoretical hydraulic forces. Real output is usually lower after seal friction, back pressure, pressure drop and mechanical losses.
Method & assumptions
- Theoretical hydraulic force only; friction, back-pressure and pressure drop are not included.
- Rod buckling, mounting strength and side load are separate cylinder selection checks.
- Flow-to-speed assumes incompressible oil and no leakage.