Bend Allowance Calculator

What is bend allowance?

The bending allowance is a value used to calculate the length of the sheet after bending.

If the materials are different, the plate thickness is different, and the bending die is different, the bending coefficient is different.

The bending unfolding allowance is a data-based thing summarized by experienced mold designers through repeated verification based on years of design experience.

Later mold designers can directly insert the calculation formula to obtain the unfolding plate size of the bending structure.

Bend allowance calculation method

Bending allowance and bending deduction calculation are the methods you can choose to determine the flat length of sheet metal raw materials, so as to obtain the required bending part size.

Bend allowance calculation method:

Bend Allowance Calculator 1

The following equation is used to determine the total flattening length when the bending allowance value is used:

Lt = A + B + BA

Wherein:
·Lt is the total flat length
·A and B are shown in the figure
·BA is the bending allowance value

Bend deduction calculation method:

Bend Allowance Calculator 2

The following equation is used to determine the total flattening length when using the bend deduction value:

Lt = A + B – BD

Wherein:
·Lt is the total flat length
·A and B are shown in the figure
·BD is the bending deduction value

Other calculation methods include bending allowance chart, K-factor and bending calculation.

Some new press brake operators may not know how to calculate the bend allowance for your press brake.

In order to facilitate your daily work, we made this bend allowance calculator, hoping to be useful to you.

You can watch the following video to learn more about bend allowance.

Bend Allowance Calculator 3


Further reading:

Bend allowance chart

Bend allowance chart for SPCC (mild steel)

Material Thickness Bending angle V opening Inner radius Bends Allowance
SPCC 0.5 90 V4 0.5 0.95
100 0.73
135 0.3
175 0.03
   
SPCC 0.5 90 V5 0.5 1.03
100 0.79
135 0.33
175 0.03
   
SPCC 0.5 90 V6 0.5 1.1
100 0.85
135 0.35
175 0.03
   
SPCC 0.6 90 V4 0.5 1.08
100 0.83
135 0.35
175 0.03
   
SPCC 0.6 90 V5 0.5 1.15
100 0.89
135 0.37
175 0.03
   
SPCC 0.6 90 V6 0.5 1.23
100 0.95
135 0.39
175 0.03
   
SPCC 0.8 90 V6 0.5 1.49
120 0.73
135 0.47
150 0.25
   
SPCC 0.8 90 V8 0 1.64
120 0.81
135 0.52
150 0.27
   
SPCC 0.8 90 V10 0 1.79
120 0.88
135 0.57
150 0.3
   
SPCC 1 90 V10 0 2.05
100 1.58
120 1.01
135 0.62
175 0.06
SPCC 1 90 V8 0 1.9
100 1.47
120 0.93
135 0.6
175 0.05
SPCC 1 90 V6 0 1.74
100 1.35
120 0.86
135 0.56
175 0.05
SPCC 1.2 90 V10 1.4 2.31
100 1.78
120 1.13
135 0.73
175 0.06
SPCC 1.2 90 V8 1.4 2.15
100 1.66
120 1.06
135 0.69
175 0.06
SPCC 1.2 90 V6 1.4 2
100 1.55
120 0.98
135 0.64
175 0.05
SPCC 1.5 90 V6 1.7 2.36
100 1.82
120 1.16
135 0.75
175 0.06
SPCC 1.5 90 V12 1.7 2.8
100 2.17
120 1.38
135 0.89
175 0.08
SPCC 1.5 90 V10 1.7 2.65
100 2.05
120 1.31
135 0.85
175 0.07
SPCC 1.5 90 V8 1.7 2.5
100 1.94
120 1.23
135 0.8
175 0.07
SPCC 2 90 V10 2 3.29
100 2.54
120 1.62
135 1.05
175 0.09
SPCC 2 90 V12 2 3.44
100 2.66
120 1.69
135 1.1
175 0.09
SPCC 2.5 90 V18 3.03 4.6
100 3.56
120 2.26
135 1.47
175 0.12
SPCC 2.5 90 V12 3.03 4.15
100 3.21
120 2.04
135 1.32
175 0.11
SPCC 2.5 90 V10 3.03 4
100 3.09
120 1.97
135 1.28
175 0.11
SPCC 3 90 V18 3.133.13 5.22
100 4.03
120 2.57
135 1.66
175 0.14
SPCC 3 90 V12 3.13 4.78
100 3.69
120 2.35
135 1.52
175 0.13
SPCC 3 90 V10 3.13 4.63
100 3.58
120 2.28
135 1.48
175 0.13

Bend allowance chart for SUS (stainless steel)

Material Thickness Bending angle V opening Inner radius Bends Allowance
SUS 0.5 90 4 0.6 1.04
100 0.79
120 0.48
135 0.3
175 0.04
SUS 0.5 90 5 0.6 1.15
100 0.88
120 0.54
135 0.33
175 0.04
SUS 0.5 90 6 0.6 1.27
100 1.13
120 0.59
135 0.37
175 0.04
SUS 0.6 90 4 0.6 1.16
100 0.88
120 0.54
135 0.34
175 0.04
SUS 0.6 90 5 0.6 1.27
100 0.97
120 0.59
135 0.37
175 0.04
SUS 0.6 90 6 0.6 1.38
100 1.05
120 0.64
135 0.4
175 0.05
SUS 0.8 90 4 1.1 1.4
100 1.06
120 0.65
135 0.4
175 0.05
SUS 0.8 90 5 1.1 1.51
100 1.15
120 0.7
135 0.44
175 0.05
SUS 0.8 90 6 1.1 1.62
100 1.23
120 0.75
135 0.47
175 0.06
SUS 1 90 6 1.9 1.87
100 1.42
120 0.87
135 0.54
175 0.07
SUS 1 90 8 1.9 2.1
100 1.6
120 0.98
135 0.61
175 0.07
SUS 1.2 90 6 1.6 2.1
100 1.59
120 0.97
135 0.61
175 0.07
SUS 1.2 90 8 1.6 2.32
100 1.76
120 1.08
135 0.67
175 0.08
SUS 1.2 90 10 1.6 2.54
100 1.93
120 1.18
135 0.74
175 0.09
SUS 1.5 90 8 2.1 2.68
100 2.03
120 1.24
135 0.77
175 0.09
SUS 1.5 90 10 2.1 2.9
100 2.2
120 1.35
135 0.84
175 0.1
SUS 2 90 10   3.49
100 2.65
120 1.62
135 1.01
175 0.12
SUS 2 90 12   3.7
100 2.82
120 1.72
135 1.07
175 0.13

Bend allowance chart for SPHC (stainless steel)

Material Thickness Bending angle V opening Inner radius Bends Allowance
SPHC 1 90 V10 1.86 2.05
100 1.58
120 1.01
135 0.62
175 0.06
SPHC 1 90 V8 1.86 1.9
100 1.47
120 0.93
135 0.6
175 0.05
SPHC 1 90 V6 1.86 1.74
100 1.35
120 0.86
135 0.56
175 0.05
SPHC 1.2 90 V10 1.44 2.31
100 1.78
120 1.13
135 0.73
175 0.06
SPHC 1.2 90 V8 1.44 2.15
100 1.66
120 1.06
135 0.69
175 0.06
SPHC 1.2 90 V6 1.44 2
100 1.55
120 0.98
135 0.64
175 0.05
SPHC 1.5 90 V12 1.74 2.8
100 2.17
120 1.38
135 0.89
175 0.08
SPHC 1.5 90 V10 1.74 2.65
100 2.05
120 1.31
135 0.85
175 0.07
SPHC 1.5 90 V8 1.74 2.5
100 1.94
120 1.23
135 0.8
175 0.07
SPHC 2 90 V12 2.01 3.44
100 2.66
120 1.69
135 1.1
175 0.09
SPHC 2 90 V10 2.01 3.29
100 2.54
120 1.62
135 1.05
175 0.09
SPHC 2.5 90 V18 3 4.6
100 3.25
120 2.26
135 1.47
175 0.12
SPHC 2.5 90 V12 3 4.15
100 3.21
120 2.04
135 1.32
175 0.11
SPHC 2.5 90 V10 3 4
100 3.09
120 1.97
135 1.28
175 0.11
SPHC 3 90 V18 3.1 5.22
100 4.03
120 2.57
135 1.66
175 0.14
SPHC 3 90 V12 3.1 4.78
100 3.69
120 2.35
135 1.52
175 0.13
SPHC 3 90 V10 3.1 4.63
100 3.58
120 2.28
135 1.48
175 0.13

Bend allowance chart for SECC (galvanized steel sheet)

Material Thickness Bending angle V opening Inner radius Bends Allowance
SECC 1 90 V10 1.9 2.05
100 1.58
120 1.01
135 0.62
175 0.06
SECC 1 90 V8 1.9 1.9
100 1.47
120 0.93
135 0.6
175 0.05
SECC 1 90 V6 1.9 1.74
100 1.35
120 0.86
135 0.56
175 0.05
SECC 1.2 90 V10 1.4 2.31
100 1.78
120 1.13
135 0.73
175 0.06
SECC 1.2 90 V8 1.4 2.15
100 1.66
120 1.06
135 0.69
175 0.06
SECC 1.2 90 V6 1.4 2
100 1.55
120 0.98
135 0.64
175 0.05
SECC 1.5 90 V12 1.7 2.8
100 2.17
120 1.38
135 0.89
175 0.08
SECC 1.5 90 V10 1.7 2.65
100 2.05
120 1.31
135 0.85
175 0.07
SECC 1.5 90 V8 1.7 2.5
100 1.94
120 1.23
135 0.8
175 0.07
SECC 2 90 V12 2 3.44
100 2.66
120 1.69
135 1.1
175 0.09
SECC 2 90 V10 2 3.29
100 2.54
120 1.62
135 1.05
175 0.09
SECC 2.5 90 V18 3.03 4.6
100 3.56
120 2.26
135 1.47
175 0.12
SECC 2.5 90 V12 3.03 4.15
100 3.21
120 2.01
135 1.32
175 0.11
SECC 2.5 90 V10 3.03 4
100 3.09
120 1.97
135 1.28
175 0.11
SECC 3 90 V18 3.13 5.22
100 4.03
120 2.57
135 1.66
175 0.14
SECC 3 90 V12 3.13 1.78
100 3.69
120 2.35
135 1.52
175 0.13
SECC 3 90 V10 3.13 4.63
100 3.58
120 2.28
135 1.48
175 0.13

Bend allowance chart for aluminum plate

Material Thickness Bending angle V opening Inner radius Bends Allowance
AL 0.8 90 4 0.6 1.15
100 0.81
120 0.5
135 0.36
175 0.03
AL 0.8 90 5 0.6 1.2
100 0.85
120 0.52
135 0.37
175 0.03
AL 0.8 90 6 0.6 1.25
100 0.88
120 0.54
135 0.39
175 0.03
AL 1 90 6 0.6 1.49
100 1.05
120 6.5
135 0.46
175 0.04
AL 1 90 8 0.6 1.59
100 1.13
120 0.69
135 0.5
175 0.04
AL 1.2 90 6 0.9 1.73
100 1.22
120 0.75
135 0.54
175 0.04
AL 1.2 90 8 0.9 1.82
100 1.29
120 0.79
135 0.57
175 0.05
AL 1.5 90 8 1.2 2.18
100 1.54
120 0.95
135 0.68
175 0.06
AL 1.5 90 10 1.2 2.28
100 1.61
120 0.99
135 0.71
175 0.06
AL 1.5 90 12 1.2 2.38
100 1.68
120 1.03
135 0.74
175 0.06
AL 2 90 14 1.6 3.07
100 2.17
120 1.3
135 0.93
175 0.08
AL 2 90 12 1.6 2.98
100 2.11
120 1.34
135 0.95
175 0.08
AL 2 90 18 1.6 3.25
100 2.3
120 1.42
135 1.01
175 0.08
AL 2.5 90 18 2.4 3.89
100 2.75
120 1.7
135 1.21
175 0.1
AL 3 90 18 2.5 4.5
100 3.18
120 1.96
135 1.4
175 0.1
AL 3.2 90 18 2.5 4.74
100 3.35
120 2.06
135 1.47
175 0.12
AL 4 90 40 4.6 6.77
100 4.79
120 2.95
135 2.11
175 0.17
AL 6.8 90 800 9.4 12.09
100 8.55
120 5.27
135 3.76
175 0.31

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