Hook Length Calculator for Steel Reinforcement
Calculate hook length for reinforcement bars, stirrups, bend anchorage and BBS cutting length using bar diameter, hook type and number of bars.
Bar diameter और hook type के हिसाब से reinforcement की hook length निकालें। यह tool beam, slab, column, stirrup और BBS work में useful है।
Formula Preview
Hook Length = Multiplier × d
Example
For 12 mm bar and 180° hook:
16 × 12 = 192 mm
What is Hook Length?
Hook length is the additional length provided at the end of a reinforcement bar to improve anchorage inside concrete. It is commonly shown in BBS and reinforcement detailing drawings.
Hindi Explanation
Hook length bar के end पर दी जाने वाली extra length होती है, जिससे bar concrete में अच्छे से anchor हो सके। इसे BBS cutting length में add किया जाता है।
Where to Use?
Use it for beam bars, slab bars, footing bars, column ties, stirrups, anchorage detailing and bar bending schedule checking.
Hook Length Formula
Hook length is generally calculated as a multiple of bar diameter. The multiplier depends on hook angle, reinforcement detailing requirement and project specification.
Standard Hook / U Hook
Hook Length = 16d
Used for standard 180° hook or U hook in reinforcement detailing.
90° Hook
Hook Length = 8d
Used where 90° hook anchorage is required.
135° Stirrup Hook
Hook Length = 6d
Commonly used in stirrups and ties, especially for ductile detailing.
Custom Hook
Hook Length = Custom Multiplier × d
Use this when drawing or consultant note gives a project-specific value.
Inputs Required
Output You Get
Example Hook Length Calculation
Given Data
Bar diameter, d = 12 mm
Hook type = 180° standard hook
Hook multiplier = 16d
Number of hooks = 2
Calculation
Hook length per hook = 16 × 12
Hook length per hook = 192 mm
Total hook length = 192 × 2
Total hook length = 384 mm
Related Steel Calculators
Use these related reinforcement calculators for BBS checking and site steel calculation.
Hook Length Calculator FAQs
What is hook length in reinforcement?
Hook length is the extra length provided at the end of a reinforcement bar to improve anchorage and holding inside concrete.
What is the formula for hook length?
A commonly used formula is Hook Length = Multiplier × Bar Diameter. For example, 180° hook is often taken as 16d.
What does d mean in hook length formula?
In hook length formulas, d means the diameter of the reinforcement bar.
Where is hook length used?
Hook length is used in beam bars, slab bars, stirrups, column ties, footing reinforcement and BBS cutting length.
Can I calculate hook length for stirrups?
Yes. The calculator supports stirrup hook options such as 90°, 135° and 180° hooks.
Is hook length added in cutting length?
Yes. Hook length is added to the basic bar length while calculating final cutting length.
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