Press Tonnage Calculator: Find the Right Power Press Capacity
Choosing an undersized press breaks tooling and frames; oversizing wastes lakhs in capital. This page gives you the exact formulas press shops use to calculate required tonnage for punching, blanking and bending — plus a worked example and a quick guide to matching your result to the right
Birson Forgings power press machine.
Birson Forgings has manufactured mechanical, pneumatic and friction screw presses in Ludhiana, Punjab since 1985. We are ISO 9001:2015 certified, and our presses — from 30 ton to 600 ton — run in workshops across India and worldwide.
Not sure after calculating?
Send us your part drawing and we will size the press for you, free.
What Is Press Tonnage?
Press tonnage is the maximum force a power press can deliver at the bottom of its stroke, expressed in metric tons. Every operation — punching, blanking, piercing, trimming, bending, drawing or forging — needs a specific force to shear or form the metal.
Your press must deliver more than that force, with a safety margin, every stroke, all shift long.
Press Tonnage Formula for Punching and Blanking For any cutting operation, required force depends on three things: length of the cut edge, material thickness, and the material's shear strength.
Tonnage = (Cut Perimeter mm × Thickness mm × Shear Strength kg/mm²) ÷ 1000 For a round hole, cut perimeter = 3.1416 × diameter. For a blank, use the full outline length. If a die cuts multiple holes in one stroke, add all perimeters together.
Bending needs far less force than cutting the same material — but if your die coins or bottoms the bend, force can multiply 3–5 times.
Tell us your die design and we will factor this in.
Why You Must Add a Safety Margin Material variation: shear strength varies batch to batch; sheet often arrives harder than specified.Tool wear: dull punches can raise cutting force by 20% or more.Rating point: a mechanical press delivers rated tonnage only near bottom dead centre; forming higher up the stroke reduces available force.Rule of thumb: select a press rated at least 30% above your calculated requirement. Running a press at 100% of rating every stroke shortens clutch, crankshaft and frame life.
Match Your Tonnage to a Birson Press Calculated Requirement Recommended Machine Typical Operations Up to 75 ton C-Frame Power Press (30–150 ton)Piercing,
small blanking,
bending75–300 ton H-Frame Power Press (30–300 ton)
Heavy blanking, trimming,
progressive dies50–600 ton (forging)Friction Screw Press,
Down-Stroke Hot forging, coining, embossing, sizing Forging, up-stroke Forging Screw Press,
Up-Stroke Hot forgings, brass and non-ferrous parts High-speed stamping Cross Shaft / Pneumatic Press Continuous stamping with coil feed lines
Why Buy Your Power Press from Birson Forgings Manufacturing presses in Ludhiana since 1985 — four decades of press-building experience. ISO 9001:2015 certified, with in-house quality inspection at every build stage.
Full range under one roof: mechanical, pneumatic and friction screw presses, 30–600 ton.
Customization: frame design, stroke, bed size and automation to match your die and part.
Exported worldwide with pre-shipment load testing and documentation.
Frequently Asked Questions
How do I calculate press tonnage for punching?
Multiply the cut perimeter (mm) by material thickness (mm) by the material's shear strength (kg/mm²), then divide by 1000. Add a 30% safety margin and choose the next standard press size up.
What tonnage press do I need to punch a 20 mm hole in 5 mm mild steel?
Perimeter 62.8 mm × 5 mm × 35 kg/mm² ÷ 1000 = 11 tons. With a 30% margin, a 30 ton press handles it comfortably, with capacity left for multi-hole dies later.
Is press tonnage the same for cutting and bending?
No. Bending typically needs far less force than cutting the same length and thickness — unless the die bottoms or coins the bend, which can multiply force 3–5 times.
What happens if I use a press with too little tonnage?
The press stalls at bottom dead centre, the clutch slips and overheats, and repeated overloading can crack the frame or bend the crankshaft. These failures are not economically repairable.
Can Birson Forgings size the press for my part? Yes.
Send your part drawing on WhatsApp (+91 98147-15935) or email info@birsonforgings.com and our engineers will calculate tonnage and recommend a machine,
free of charge.Get an Exact Recommendation
A formula gets you close; forty years of press building gets it right.
Share your part, material and production rate — Birson Forgings will confirm the tonnage, frame type and bed size you need, and quote a machine built to it.
Call +91 98147-15935 or contact us today.