Free Engineering Tool
Convert a known working force, blanking estimate or hydraulic cylinder force into kN, metric tons and US short tons, then apply a machine-capacity allowance.
This is a press-sizing calculator for general machine selection. Use the blanking and stamping force calculator when you need detailed shear area, material shear strength and punch compressive stress. Use the press-brake tonnage calculator for air bending.
Press tonnage is the rated working force of a press, usually stated in kN, metric tons or US short tons. General press sizing starts with the peak force required by the process: blanking uses cut perimeter × thickness × shear strength; hydraulic force uses piston area × pressure; and a measured load can be entered directly. Convert kN to metric tons by dividing by 9.80665, or to US short tons by dividing by 8.89644, because the two ton units are not interchangeable. A 500 kN load is about 51.0 metric tons and 56.2 US short tons. After calculation, add an allowance for material variation and process losses, then check the press tonnage curve, bed size, shut height, off-centre loading and tooling limits. Zhejiang Balford Mechatronics Co., Ltd. reviews stamping projects against presses rated from 25 to 350 t; the final selection still depends on the specific die and part.
Rated press tonnage is not the only selection limit. Check the machine tonnage curve, shut height, bed size, off-centre loading limit and die protection. For a progressive die, the peak sum across active stations matters.
The calculation starts with the working force and then applies an allowance before comparing that load with a machine rating.
| kN | Metric tons | US short tons | Equivalent load |
|---|---|---|---|
| 100 | 10.2 | 11.2 | Small press-brake or assembly press |
| 250 | 25.5 | 28.1 | Blanking, piercing or light bending duty |
| 500 | 51.0 | 56.2 | General press sizing reference |
| 1,000 | 102.0 | 112.4 | High-force process; check the machine curve |
| 2,500 | 254.9 | 281.0 | Large press; verify frame and tooling limits |
| 5,000 | 509.9 | 562.0 | Large press; engineering review required |
Conversions are exact for the stated force; process suitability is not. Always verify the machine tonnage curve, die load and safety limits.
A hydraulic cylinder has a 100 mm bore and receives 160 bar. Pressure is 16 MPa and the bore area is π × 100² / 4 = 7,854 mm². Theoretical extending force is 125.7 kN, or about 12.8 metric tons and 14.1 US short tons.
Press tonnage is the rated force a press can apply, normally stated in metric tons, US short tons or kN. A press must have enough force for the peak load of the process, and the load must also be usable within the machine's tonnage curve, bed and ram limits.
Divide kN by 9.80665 for metric tons, or by 8.89644 for US short tons. For example, 500 kN is about 51.0 metric tons or 56.2 US short tons.
A first estimate is F = cut perimeter × sheet thickness × shear strength. For exact shear area, shear-strength selection and punch stress, use the dedicated blanking and stamping force calculator linked from this page.
Hydraulic force is pressure multiplied by effective piston area. For a round bore, F = π × D² / 4 × pressure. The result is the theoretical extending force; the actual usable force is lower because of friction, pressure losses and the selected circuit.
Add the simultaneous loads of all active stations, not only the largest single station. The peak can occur at a specific crank angle. Also check off-centre loading, die deflection, cushion force and stripping force with the press manufacturer's data.
Send the operation, material, tooling data and required output so the working force and machine limits can be checked together. Send the drawing to shawn@balford.net. We normally reply within 24 hours, China Standard Time.