Guides — Tonnage Chart
Press brake tonnage chart (air bending, mild steel)
By Jon Chacon · October 22, 2026
This is the chart that used to hang on the wall, rebuilt straight from the formula so the numbers are out in the open. Tons per foot for air bending mild steel — find the thickness, find the die opening, read the force.
Tons per foot = 575 × (thickness in inches)² ÷ V-opening in inches
| Thickness \ V-opening | 0.5″ | 0.75″ | 1″ | 1.25″ | 1.5″ | 2″ | 2.5″ | 3″ | 4″ |
|---|---|---|---|---|---|---|---|---|---|
| 0.060″ (16 ga) | 4.1 | 2.8 | 2.1 | 1.7 | 1.4 | 1.0 | 0.8 | 0.7 | 0.5 |
| 0.075″ (14 ga) | 6.5 | 4.3 | 3.2 | 2.6 | 2.2 | 1.6 | 1.3 | 1.1 | 0.8 |
| 0.105″ (12 ga) | 12.7 | 8.5 | 6.3 | 5.1 | 4.2 | 3.2 | 2.5 | 2.1 | 1.6 |
| 0.120″ (11 ga) | 16.6 | 11.0 | 8.3 | 6.6 | 5.5 | 4.1 | 3.3 | 2.8 | 2.1 |
| 0.125″ (1/8) | 18.0 | 12.0 | 9.0 | 7.2 | 6.0 | 4.5 | 3.6 | 3.0 | 2.2 |
| 0.135″ (10 ga) | 21.0 | 14.0 | 10.5 | 8.4 | 7.0 | 5.2 | 4.2 | 3.5 | 2.6 |
| 0.188″ (3/16) | 40.4 | 27.0 | 20.2 | 16.2 | 13.5 | 10.1 | 8.1 | 6.7 | 5.1 |
| 0.250″ (1/4) | 71.9 | 47.9 | 35.9 | 28.8 | 24.0 | 18.0 | 14.4 | 12.0 | 9.0 |
| 0.313″ (5/16) | 112.3 | 74.9 | 56.2 | 44.9 | 37.4 | 28.1 | 22.5 | 18.7 | 14.0 |
| 0.375″ (3/8) | 161.7 | 107.8 | 80.9 | 64.7 | 53.9 | 40.4 | 32.3 | 27.0 | 20.2 |
| 0.500″ (1/2) | 287.5 | 191.7 | 143.8 | 115.0 | 95.8 | 71.9 | 57.5 | 47.9 | 35.9 |
The bottom-left corner of that table — thick material on narrow openings — is shown because the math works out. In the shop, openings under about six times the thickness are hard on tooling and material, and some of those combinations won’t form at all. Treat that corner with suspicion.
How to read this chart
Find your material’s table. Pick your thickness down the left side, pick your die opening across the top, and the number where they meet is your tons per foot. Multiply that by your bend length in feet and that’s the total force the bend takes — before your safety factor. Quarter-inch mild steel in a 2-inch die reads 18.0 tons per foot, so a 5-foot bend needs about 90 tons.
Stop trusting the chart when the flange is short, the radius is tight, or the material isn’t run-of-the-mill mild steel — that’s where the number on paper and the number on the gauge part ways. Run those jobs through the free tonnage calculator instead, and leave your safety factor on top either way.
Stainless steel — tons per foot
Stainless figured at 1.5× the mild steel chart — the working rule from the “Other materials” section below, laid out as its own table so nobody has to do the multiplying at the machine.
| Thickness \ V-opening | 0.5″ | 0.75″ | 1″ | 1.25″ | 1.5″ | 2″ | 2.5″ | 3″ | 4″ |
|---|---|---|---|---|---|---|---|---|---|
| 0.060″ (16 ga) | 6.2 | 4.2 | 3.2 | 2.6 | 2.1 | 1.5 | 1.2 | 1.1 | 0.8 |
| 0.075″ (14 ga) | 9.8 | 6.5 | 4.8 | 3.9 | 3.3 | 2.4 | 2.0 | 1.7 | 1.2 |
| 0.105″ (12 ga) | 19.1 | 12.8 | 9.5 | 7.7 | 6.3 | 4.8 | 3.8 | 3.2 | 2.4 |
| 0.120″ (11 ga) | 24.9 | 16.5 | 12.5 | 9.9 | 8.3 | 6.2 | 5.0 | 4.2 | 3.2 |
| 0.125″ (1/8) | 27.0 | 18.0 | 13.5 | 10.8 | 9.0 | 6.8 | 5.4 | 4.5 | 3.3 |
| 0.135″ (10 ga) | 31.5 | 21.0 | 15.8 | 12.6 | 10.5 | 7.8 | 6.3 | 5.3 | 3.9 |
| 0.188″ (3/16) | 60.6 | 40.5 | 30.3 | 24.3 | 20.3 | 15.2 | 12.2 | 10.1 | 7.7 |
| 0.250″ (1/4) | 107.9 | 71.9 | 53.9 | 43.2 | 36.0 | 27.0 | 21.6 | 18.0 | 13.5 |
| 0.313″ (5/16) | 168.5 | 112.4 | 84.3 | 67.4 | 56.1 | 42.2 | 33.8 | 28.1 | 21.0 |
| 0.375″ (3/8) | 242.6 | 161.7 | 121.4 | 97.1 | 80.9 | 60.6 | 48.5 | 40.5 | 30.3 |
| 0.500″ (1/2) | 431.3 | 287.6 | 215.7 | 172.5 | 143.7 | 107.9 | 86.3 | 71.9 | 53.9 |
Aluminum — tons per foot
Aluminum figured at 0.5× the mild steel chart — about half the force, same openings, same reading method.
| Thickness \ V-opening | 0.5″ | 0.75″ | 1″ | 1.25″ | 1.5″ | 2″ | 2.5″ | 3″ | 4″ |
|---|---|---|---|---|---|---|---|---|---|
| 0.060″ (16 ga) | 2.1 | 1.4 | 1.1 | 0.9 | 0.7 | 0.5 | 0.4 | 0.4 | 0.3 |
| 0.075″ (14 ga) | 3.3 | 2.2 | 1.6 | 1.3 | 1.1 | 0.8 | 0.7 | 0.6 | 0.4 |
| 0.105″ (12 ga) | 6.4 | 4.3 | 3.2 | 2.6 | 2.1 | 1.6 | 1.3 | 1.1 | 0.8 |
| 0.120″ (11 ga) | 8.3 | 5.5 | 4.2 | 3.3 | 2.8 | 2.1 | 1.7 | 1.4 | 1.1 |
| 0.125″ (1/8) | 9.0 | 6.0 | 4.5 | 3.6 | 3.0 | 2.3 | 1.8 | 1.5 | 1.1 |
| 0.135″ (10 ga) | 10.5 | 7.0 | 5.3 | 4.2 | 3.5 | 2.6 | 2.1 | 1.8 | 1.3 |
| 0.188″ (3/16) | 20.2 | 13.5 | 10.1 | 8.1 | 6.8 | 5.1 | 4.1 | 3.4 | 2.6 |
| 0.250″ (1/4) | 36.0 | 24.0 | 18.0 | 14.4 | 12.0 | 9.0 | 7.2 | 6.0 | 4.5 |
| 0.313″ (5/16) | 56.2 | 37.5 | 28.1 | 22.5 | 18.7 | 14.1 | 11.3 | 9.4 | 7.0 |
| 0.375″ (3/8) | 80.9 | 53.9 | 40.5 | 32.4 | 27.0 | 20.2 | 16.2 | 13.5 | 10.1 |
| 0.500″ (1/2) | 143.8 | 95.9 | 71.9 | 57.5 | 47.9 | 36.0 | 28.8 | 24.0 | 18.0 |
What the chart assumes
- Air bending. Bottoming or coining the same part takes multiples more force. This chart is not for those.
- Mild steel, about 60,000 psi tensile. That’s the material the 575 constant is built on.
- Thickness at nominal. Plate that runs over nominal needs more force, and thickness is squared, so a little over counts a lot.
- Estimates, end to end. Two lots of “the same” steel don’t bend exactly alike. Plan with the chart, leave your safety factor on top.
Other materials
As working rules of thumb: stainless figures about 1.5× the chart, and aluminum about 0.5×. Multiply the chart number by the factor for your material, and remember both are approximations — the bigger the job, the more a test bend is worth.
What a chart can’t do
A chart can’t check your die inventory, your machine’s limit, or what happens when a short part puts all of its force through two feet of tooling. It can’t save the setup for the next time the job runs, either. The full explanation of the math is in How press brake tonnage is calculated, and Picking a V-die for air bending covers choosing the opening in the first place. Or skip the table entirely and run your own numbers in the free tonnage calculator.
Questions we get asked
How do I read the chart?
Find your thickness in the left column and your die opening across the top. The number where they meet is tons per foot. Multiply by your bend length in feet for the total. Quarter-inch in a 2-inch die reads 18.0 tons per foot, so a 5-foot bend needs about 90 tons — before your safety factor.
The chart and my brake’s gauge don’t agree. Who’s right?
The gauge, on that part, in that material. The chart assumes nominal thickness and average mild steel. Your material is a specific lot that runs a little thicker or a little stronger than the book value, and thickness counts double because it’s squared. Use the chart to plan the setup, and trust the machine about the material you actually bent.
Does this chart cover stainless or aluminum?
Not directly. As working rules, figure stainless at about 1.5 times the chart number and aluminum at about half — then treat the result as the estimate it is, and check it against your tooling and machine limits the same as any other number.
A chart gives you one number for one bend. Precision Form runs the same check against the dies actually in your rack, flags the setup if the tonnage is over, and saves it so the next run comes out the same. Free 14-day trial — no credit card required.
Run your own numbers — free 14-day trial, no credit card.
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