Punch and Die Design Calculator

Formula

• Clearance c = (clearance %) × thickness
• F_cut = 0.8 × UTS × thickness × perimeter
• Press tonnage = total force (kN) / 9.81

About this calculator

Part of our Manufacturing Calculators collection. Welding, stamping, punch and die tooling, 3D printing, material weight, and production automation.

How it works

Cutting force uses shear strength approximated as 0.8 times UTS times shear perimeter times thickness. Clearance per side is a percentage of sheet thickness. Press tonnage converts total force to metric tons for press selection.

Enter your values in the inputs above and click CALCULATE. Results appear on the right without a page reload. No login and no server upload.

Worked example

Blank 25 mm diameter, 2 mm mild steel (UTS 420 MPa), 5% clearance, blanking.

1. Perimeter = π × 25 = 78.5 mm
2. Shear stress ≈ 0.8 × 420 = 336 MPa
3. Cutting force = 336 × 2 × 78.5 / 1000 = 52.8 kN
4. Press tonnage ≈ 6.7 T (with stripper and safety factor)

Result: Punch 24.8 mm, die 25.0 mm, ~6.7 metric tons.

When to use

• First-pass press tonnage for blanking or piercing
• Punch and die size with clearance
• Stripper force estimation

Limitations

• Shear strength = 0.8×UTS is approximate
• Does not model progressive dies or compound tooling
• Verify tonnage with tooling supplier for production

FAQ

Blanking vs piercing punch size?

Blanking: punch = part size, die = part + 2×clearance. Piercing: punch = hole − 2×clearance, die = hole size.

What clearance should I use?

Soft steel often uses 5–10% of thickness per side. Harder materials may need more clearance.

Why 0.8 × UTS?

Shear strength in punching is typically 60–80% of tensile strength. This tool uses 80% as a conservative default.