Steel BBS Calculator

Bend Deduction Calculator for Steel Reinforcement

Calculate bend deduction for reinforcement bars for 45°, 90°, 135°, 180° and custom bends. Use it for BBS, stirrup length, crank bar length and cutting length calculations.

Bar diameter, bend angle और number of bends डालकर bend deduction निकालें। यह tool BBS cutting length, stirrup, crank bar और bent reinforcement के लिए useful है।

Formula Preview

Total Deduction = Multiplier × d × Bends

Example

For 12 mm bar, 90° bend and 4 bends:

2 × 12 × 4 = 96 mm

What is Bend Deduction?

Bend deduction is the length adjustment applied while calculating the cutting length of bent reinforcement bars. It helps prepare a practical and accurate Bar Bending Schedule.

Hindi Explanation

Bend deduction steel bar के bend होने पर cutting length में किया जाने वाला adjustment है। BBS में सही cutting length निकालने के लिए bend deduction minus किया जाता है।

Where to Use?

Use it in stirrups, column ties, beam bars, crank bars, L bars, U bars, hooks and all BBS cutting length calculations involving bends.

Bend Deduction Formula

Bend deduction is commonly calculated as a multiple of bar diameter. The multiplier depends on bend angle and project-specific BBS practice. In practical site calculations, 45°, 90°, 135° and 180° bends are usually handled with standard multipliers.

45° Bend Deduction

Bend Deduction = 1d

Commonly used deduction for 45° reinforcement bend in BBS calculations.

90° Bend Deduction

Bend Deduction = 2d

Commonly used for L bars, crank bars, stirrups and 90° bent reinforcement.

135° Bend Deduction

Bend Deduction = 3d

Useful for stirrup hooks, ties and ductile detailing cases.

180° Bend Deduction

Bend Deduction = 4d

Used for U hooks, 180° bends and bar anchorage detailing.

Total Bend Deduction

Total Deduction = Deduction per Bend × Number of Bends

Used when a bar has multiple bends in BBS cutting length calculation.

Custom Bend Deduction

Total Deduction = Custom Multiplier × d × Number of Bends

Use this when drawing, site practice or consultant note gives custom deduction.

Example Bend Deduction Calculation

Given Data

Bar diameter, d = 12 mm

Bend angle = 90°

Deduction for 90° bend = 2d

Number of bends = 4

Calculation

Deduction per bend = 2 × 12

Deduction per bend = 24 mm

Total deduction = 24 × 4

Total Bend Deduction = 96 mm

Inputs Required

Unit system: Metric or Imperial
Bar diameter
Bend angle: 45°, 90°, 135°, 180° or custom angle
Number of bends
Deduction method: Standard BBS, angle based, custom or no deduction
Custom multiplier, if required
Steel rate, optional
Bar mark and member name, optional

Output You Get

Deduction per bend
Total bend deduction
Selected bend formula
Number of bends
Steel weight equivalent
Cost equivalent
Step-by-step solution
Dynamic bend diagram

Bend Deduction in BBS Cutting Length

In Bar Bending Schedule, cutting length is calculated by adding required straight lengths, hook lengths, lap lengths and development lengths, then subtracting bend deductions. This prevents over-cutting and helps maintain consistent reinforcement quantity.

Stirrups

Stirrups have multiple bends, so bend deduction is important for practical cutting length and steel wastage control.

Crank Bars

Crank bars or bent-up bars include inclined parts and bends, so bend deduction helps refine final cutting length.

L Bars and U Bars

L bars and U bars are common in beams, footings and anchorage detailing where bend deduction is required.

Related Steel Calculators

Use these related tools for complete steel reinforcement and BBS calculation workflow.

Bend Deduction Calculator FAQs

What is bend deduction in reinforcement?

Bend deduction is the length deducted from reinforcement cutting length because bending a steel bar changes its effective length.

Why is bend deduction required in BBS?

Bend deduction is required in Bar Bending Schedule to calculate practical cutting length of reinforcement bars after considering bends.

What is the bend deduction for 90° bend?

A commonly used BBS deduction for a 90° bend is 2d, where d is the diameter of the bar.

What is the bend deduction for 45° bend?

A commonly used bend deduction for a 45° bend is 1d.

What is the bend deduction for 135° bend?

A commonly used bend deduction for a 135° bend is 3d.

What does d mean in bend deduction formula?

In bend deduction formulas, d means the diameter of the reinforcement bar.

Where is bend deduction used?

Bend deduction is used in stirrups, crank bars, L bars, U bars, hooks, beam bars, column ties and BBS cutting length calculations.

Is bend deduction always required?

Bend deduction is required when cutting length is calculated from external dimensions or centerline assumptions. If drawing already gives adjusted cutting length, deduction may not be required.

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