Rebar Development Length Calculator

Compute the embedment a bar needs to develop its full strength. Select the bar size, steel grade and concrete grade, and the tool returns Ld in mm and as a multiple of bar diameter, for tension or compression.

0

How to use: Rebar Development Length Calculator

Pick the bar size.
Select steel grade (Fe250–Fe550) and concrete grade (M20–M40).
Choose tension or compression to read Ld.

Formula

Ld = (φ × 0.87 × fy) ÷ (4 × τbd). τbd is the design bond stress (increased 60% for deformed bars, +25% for compression).

See the full rebar weight chart (kg/m & lb/ft) →

Rebar Development Length Calculator — FAQ

What is development length of rebar?

The length of bar that must be embedded in concrete to transfer its design force safely.

What is the development length for Fe500 in M25?

About 47–49 times the bar diameter in tension for deformed bars.