Enter Hydraulic Cylinder Data
Example Data Table
| Case | Bore | Rod | Pressure | Efficiency | Approx Extension Tonnage | Typical Use |
|---|---|---|---|---|---|---|
| Small press | 80 mm | 35 mm | 160 bar | 90% | 7.38 metric tons | Light forming |
| Workshop lift | 100 mm | 45 mm | 180 bar | 90% | 12.97 metric tons | Controlled lifting |
| Heavy clamp | 150 mm | 70 mm | 210 bar | 88% | 33.30 metric tons | Clamping force |
Formula Used
Bore area: A = π × D² / 4
Rod area: Ar = π × d² / 4
Retraction area: Aret = A - Ar
Extension force: F = P × A × n × η
Retraction force: Fr = P × Aret × n × η
Metric tonnage: T = F / 9806.65
Safe working tonnage: Tsafe = T / safety factor
Hydraulic power: kW = pressure(Pa) × flow(m³/s) / 1000
Three phase current: I = W / (√3 × V × PF)
How to Use This Calculator
Enter the cylinder bore diameter first. Then enter the rod diameter. Choose the correct unit for both values.
Add the working hydraulic pressure. Use the real operating pressure, not only the maximum pump rating.
Enter stroke length and cycle time to estimate oil volume and required pump flow. Add the number of cylinders when cylinders act together.
Use efficiency to account for friction, seal drag, and system losses. Use the safety factor field for safer design checks.
Enter a target load if you want to compare available tonnage with the required load. The calculator also estimates motor power and electrical current.
Press the calculate button. The result will appear above the form. Use the CSV or PDF buttons to save the output.
Hydraulic Cylinder Tonnage Planning Guide
Why Tonnage Matters
Hydraulic cylinder tonnage shows the usable pushing or pulling capacity of a cylinder. It is important in presses, lifts, clamps, jacks, and industrial motion systems. A small change in bore size can create a large change in force. Pressure also has a direct effect. For this reason, both values must be checked together.
Extension and Retraction
The extension side uses the full piston area. The retraction side loses area because the rod occupies space. This makes pulling force lower than pushing force in most single rod cylinders. The calculator displays both values. This helps users avoid undersized designs. It also helps compare cylinder options before purchase.
Safety and Efficiency
Real systems do not convert all pressure into useful work. Seal friction, hose losses, valve drops, oil temperature, and mechanical alignment reduce output. Efficiency gives a more realistic result. The safety factor then reduces the rated value for safer planning. This is useful when loads may shift, bind, or shock the system.
Electrical Power View
Hydraulic work often depends on an electric motor and pump. High pressure and high flow need more power. The tool estimates hydraulic power, motor power, horsepower, and current. These results are useful for electrical panel planning. They also help compare pump sizes and motor ratings.
Design Notes
Always confirm cylinder ratings from the manufacturer. Check mounting strength, pin shear, hose rating, valve capacity, and frame deflection. Long strokes may also need buckling checks. Use this calculator for planning and comparison. Final designs should be reviewed by a qualified engineer when safety is critical.
FAQs
1. What is hydraulic cylinder tonnage?
It is the force output expressed in tons. It depends on hydraulic pressure, piston area, cylinder quantity, and efficiency.
2. Why is retraction tonnage lower?
The rod reduces the effective piston area during retraction. Less area means less force at the same pressure.
3. Which pressure value should I enter?
Enter the actual working pressure under load. Do not use the relief valve rating unless the system truly operates there.
4. What efficiency value is realistic?
Many practical systems use 85% to 95%. Lower values may fit worn cylinders, high friction, or poor hydraulic layouts.
5. What does safety factor mean?
It reduces the calculated force for safer working capacity. A higher safety factor gives a more conservative design result.
6. Can this calculator estimate motor size?
Yes. It uses pressure, flow, and efficiency to estimate motor kilowatts, horsepower, and approximate current draw.
7. Does stroke length change tonnage?
No. Stroke length changes oil volume and speed needs. Force mainly depends on pressure and effective piston area.
8. Is this suitable for final machine design?
Use it for planning and comparison. For critical lifting, pressing, or safety systems, get an engineer to verify the design.