The box height calculator checks whether a box or pan can be bent without the last side hitting the press brake beam. Box height = 0.672 × (upper tool height − D), where D is the distance from the beam center to its outer edge. A 120 mm punch with D = 30 mm bends boxes up to 60.5 mm deep.
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Results
LiveMaximum box internal heightdeepest box side you can bend
- Box internal height
- 60.5 mm
- Upper tool height
- 120.0 mm
- Beam center to edge (D)
- 30.0 mm
Box height formulas
Hbox = 0.672 × (Htool − D)
Htool = Hbox / 0.672 + D
When the last side of a box is bent, the sides already formed rise up beside the punch. If they are taller than the free height under the beam and clamps, they collide. Tall punches (box or segmented “finger” tools) increase the free height. The 0.672 factor accounts for the rotation of the side during the bend.
How to use the Box Height Calculator
- Choose whether you want the maximum box height or the required tool height.
- Enter the punch height or the box height.
- Enter D, the distance from the beam center line to its outer edge.
Worked example
120 mm upper tool, D = 30 mm. Hbox = 0.672 × (120 − 30) = 60.5 mm. To bend an 80 mm deep box you would need a tool of at least 80 / 0.672 + 30 = 149 mm.
Box height quick reference (mm)
| Upper tool height | D | Max. box height |
|---|---|---|
| 100 | 30 | 47.0 |
| 120 | 30 | 60.5 |
| 150 | 40 | 73.9 |
| 200 | 40 | 107.5 |
| 250 | 50 | 134.4 |
| 300 | 50 | 168.0 |
Frequently asked questions
How deep a box can I bend on a press brake?
About 0.67 times the free height between the beam edge and the punch tip. With standard 120 mm punches that is roughly 60 mm; tall box punches of 200–250 mm allow boxes of 110–140 mm.
What tooling is used for box bending?
Segmented (finger) punches of the right total length, with enough height to clear the formed sides, and a press brake with enough open height and stroke.
What else limits box bending?
Open height and stroke of the press brake, the depth of the throat, and the length of segmented tooling needed for the inside of the box.
Reviewed by the HARSLE engineering team · Last updated October 2026. Results are engineering estimates; confirm critical values with your machine and tooling documentation.
Maximum box internal height—