Torque Extension Calculator

Calculate the correct torque wrench setting when using a rigid extension or crowfoot attachment.

in-lb

At the fastener

in

Handle center to drive center

in

Drive center to fastener center

Enter values above to calculate

Geometry Diagram

TL (wrench)E (extension)

How This Works

When a rigid extension or crowfoot wrench is added to a torque wrench, the effective lever arm changes. Without adjusting the wrench setting, you will over-torque the fastener.

TW = (T × L) / (L + E)

T = TW × (L + E) / L   ← reverse mode

  • TW — Torque wrench setting (what you set the wrench to)
  • T — Desired torque at the fastener
  • L — Distance from center of handle grip to center of drive
  • E — Distance from center of drive to center of fastener

⚠ This formula only applies to extensions that are in-line with the wrench. For angle extensions, consult your maintenance manual.

Important Disclaimer

This tool is provided for educational and reference purposes only. Always verify all calculations against FAA-approved maintenance manuals, aircraft documentation, and applicable regulations. Never use web-based tools as the sole basis for airworthiness decisions.