RSJ bearing and order length calculator

Add entered equal end bearings to a clear opening to illustrate total length. This tool does not design bearings or issue cutting instructions.

How to use this tool

  1. Enter the clear opening width and the equal bearing length at each end from your design.
  2. Enter the whole quantity and calculate the arithmetic total.
  3. Use the issued fabrication drawing for an order. This tool does not establish a suitable bearing or allow for every connection detail.

Bearing Length Calculator

Convert clear span into likely order length by adding bearing at each end. The default 150 mm each side is an illustrative input only — use the specified dimensions from your drawings.

Inside face of support to inside face of support

Questions and limitations

Does the default 150 mm bearing apply to my project?

No. It is an illustrative input only. Your engineer must specify the bearings and supporting construction.

Is ordered length the same as the span used by the deflection tool?

No. This tool adds entered end bearings to a clear opening. The deflection model uses distance between idealised support centres. Use the appropriate dimensions from the design.

Data and editorial responsibility

Published by Krystian Welcel, a software developer. These tools have not received an independent structural engineering review. Read the data sources and calculation method.

Structural work must be designed by a chartered structural engineer and receive the applicable Building Control approval. These educational calculations are not construction specifications.