Is this calculation free and private?

Yes, 100% of calculations execute locally in your web browser. No inputs or personal data are stored or transmitted.

What does the Bolt Torque & Preload Clamp Force Calculator give me?

It works out Tightening Torque, Tightening Torque, Tensile Clamp Preload and Tensile Stress Area, updating live as you change the inputs.

What do I need to enter?

Just Bolt Nominal Diameter, Bolt Proof Strength, Nut Friction Factor K and Target Preload. Every field has a sensible default you can start from.

Is my data uploaded anywhere?

No. The calculation runs in your browser with JavaScript — nothing you type is sent to a server or stored.

Does it work on a phone?

Yes. The layout adapts to small screens and needs no app or signup.

Bolt Torque & Preload Clamp Force Calculator

Calculate recommended tightening torque (ft-lbs and Nm) and resulting tensile clamp preload based on bolt size, grade, and lubricated friction K.

100% free
Private in browser
No signup
No watermarks

Bolt Nominal Diameter (Inches, e.g. 0.5=1/2")

Bolt Proof Strength (PSI, Grade 5=85k, Gr 8=120k)

Nut Friction Factor K (0.20 Dry, 0.15 Lubed)

Target Preload (% of Proof Strength)

Tightening Torque (Ft-Lbs)

75.4

Tightening Torque (Newton-Meters Nm)

102.2

Tensile Clamp Preload (lbs)

9,046

Tensile Stress Area (sq in)

0.142

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About Bolt Torque & Preload Clamp Force Calculator

Calculate recommended tightening torque (ft-lbs and Nm) and resulting tensile clamp preload based on bolt size, grade, and lubricated friction K. Enter Bolt Nominal Diameter, Bolt Proof Strength and Nut Friction Factor K and the tool works out Tightening Torque, Tightening Torque and Tensile Clamp Preload straight away. Everything runs in your browser, so your data never leaves your device.

How to use Bolt Torque & Preload Clamp Force Calculator

Enter Bolt Nominal Diameter, Bolt Proof Strength and Nut Friction Factor K.
Adjust the remaining options (Target Preload) to match your case.
Read Tightening Torque, Tightening Torque and Tensile Clamp Preload in the results panel — copy or download what you need.

Key features

Shows Tightening Torque (Ft-Lbs)
Shows Tightening Torque (Newton-Meters Nm)
Shows Tensile Clamp Preload (lbs)
4 adjustable inputs, results update as you type
No signup, no limits

Frequently asked questions

Is this calculation free and private?: Yes, 100% of calculations execute locally in your web browser. No inputs or personal data are stored or transmitted.
What does the Bolt Torque & Preload Clamp Force Calculator give me?: It works out Tightening Torque, Tightening Torque, Tensile Clamp Preload and Tensile Stress Area, updating live as you change the inputs.
What do I need to enter?: Just Bolt Nominal Diameter, Bolt Proof Strength, Nut Friction Factor K and Target Preload. Every field has a sensible default you can start from.
Is my data uploaded anywhere?: No. The calculation runs in your browser with JavaScript — nothing you type is sent to a server or stored.
Does it work on a phone?: Yes. The layout adapts to small screens and needs no app or signup.

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