In this article, I have covered Flange Bolt Dimension Chart and Stud Size Dimensions for stud and bolt used in piping. The diameter and length of the stud and bolt are covered in flange standard ASME B16.5 & B16.47. You will use a bolt and stud to connect flanges.

The image shown below indicates the nomenclature used in the dimension chart.

flange bolt dimension chart

Class 150 Pipe Flange Bolt Charts

Size in Inch Size in mm No of Bolts Bolt Size UNC RF Stud Length ISO Stud Size Machine Bolt Length
Class 150 Flange
1/2 15 4 1/2 55 M14 50
3/4 20 4 1/2 65 M14 50
1 25 4 1/2 65 M14 55
1 1/4 32 4 1/2 70 M14 55
1 1/2 40 4 1/2 70 M14 65
2 50 4 5/8 85 M16 70
2 1/2 65 4 5/8 90 M16 75
3 80 4 5/8 90 M16 75
3 1/2 90 8 5/8 90 M16 75
4 100 8 5/8 90 M16 75
5 125 8 3/4 95 M20 85
6 150 8 3/4 100 M20 85
8 200 8 3/4 110 M20 90
10 250 12 7/8 115 M24 100
12 300 12 7/8 120 M24 100
14 350 12 1 135 M27 115
16 400 16 1 135 M27 115
18 450 16 1 1/8 145 M30 125
20 500 20 1 1/8 160 M30 140
24 600 20 1 1/4 170 M33 150

Class 300 Flange Bolt Charts

Size in Inch Size in mm No of Bolts Bolt Size UNC RF Stud Length ISO Stud Size Machine Bolt Length
Class 300 Flange
1/2 15 4 1/2 65 M14 55
3/4 20 4 5/8 75 M16 65
1 25 4 5/8 75 M16 65
1 1/4 32 4 5/8 85 M16 70
1 1/2 40 4 3/4 90 M20 75
2 50 8 5/8 90 M16 75
2 1/2 65 8 3/4 100 M20 85
3 80 8 3/4 110 M20 90
3 1/2 90 8 3/4 110 M20 95
4 100 8 3/4 115 M20 95
5 125 8 3/4 120 M20 110
6 150 12 3/4 120 M20 110
8 200 12 7/8 140 M24 120
10 250 16 1 160 M27 140
12 300 16 1 1/8 170 M30 145
14 350 20 1 1/8 180 M30 160
16 400 20 1 1/4 190 M33 165
18 450 24 1 1/4 195 M33 170
20 500 24 1 1/4 205 M33 185
24 600 24 1 1/2 230 M39 205

Flange and Olet Quiz – Test yourself, Take This Quiz

Unlock New Skills with Our Best Selling Online Courses

How to be an Expert in Piping Components for Oil & Gas Career - Training Course
Best Selling

How to be an Expert in Piping Components

Learn about Pipes, Fittings, Olets, Gaskets, Flanges, Bolting materials, valves, orifice flanges, Spectacle Blind, steam traps, and more.

29.99

Piping Components and Types of Valves Bundle - Training Courses
20% Discount

Piping Components and Types of Valve Bundle

Learn about Types of Piping Components and Types of Valves in this Course Bundle.

48.99

59.99

Class 400 Flange Bolt and Stud Dimension Chart

Size in Inch Size in mm No of Bolts Bolt Size UNC RF Stud Length ISO Stud Size
Class 400 Flange
1/2 15 4 1/2 75 M14
3/4 20 4 5/8 90 M16
1 25 4 5/8 90 M16
1 1/4 32 4 5/8 95 M16
1 1/2 40 4 3/4 110 M20
2 50 8 5/8 110 M16
2 1/2 65 8 3/4 120 M20
3 80 8 3/4 125 M20
3 1/2 90 8 7/8 140 M24
4 100 8 7/8 140 M24
5 125 8 7/8 145 M24
6 150 12 7/8 150 M24
8 200 12 1 170 M27
10 250 16 1 1/8 190 M30
12 300 16 1 1/4 205 M33
14 350 20 1 1/4 210 M33
16 400 20 1 3/8 220 M36
18 450 24 1 3/8 230 M36
20 500 24 1 1/2 240 M39
24 600 24 1 3/4 265 M45

Unlock New Skills with Our Best Selling Online Courses

How to Read P&ID, PFD and BFD Used in Process Plant - Training Course
Best Selling

How to Read P&ID, PFD and BFD Used in Process Plant

Learn How to Read Piping and Instrument Diagram-P&ID, Process Flow Diagram and Block Flow Diagram used in Process Plant.

29.99

P&ID, Piping Components and Valve Bundle - Training Courses
23% Discount

P&ID, Piping Components and Types of Valve Bundle

Learn to Read P&ID drawing, Types of Piping Components and Types of Valves in this Course Bundle.

69.99

89.99

Bolt Charts for Class # 600 Flanges

Size in Inch Size in mm No of Bolts Bolt Size UNC RF Stud Length ISO Stud Size
Class 600 Flange
1/2 15 4 1/2 75 M14
3/4 20 4 5/8 90 M16
1 25 4 5/8 90 M16
1 1/4 32 4 5/8 95 M16
1 1/2 40 4 3/4 110 M20
2 50 8 5/8 110 M16
2 1/2 65 8 3/4 120 M20
3 80 8 3/4 125 M20
3 1/2 90 8 7/8 140 M24
4 100 8 7/8 145 M24
5 125 8 1 165 M27
6 150 12 1 170 M27
8 200 12 1 1/8 190 M30
10 250 16 1 1/4 215 M33
12 300 20 1 1/4 220 M33
14 350 20 1 3/8 235 M36
16 400 20 1 1/2 255 M39
18 450 20 1 5/8 275 M42
20 500 24 1 5/8 285 M42
24 600 24 1 7/8 330 M48

Class 900 Flange Bolt Charts

Size in Inch Size in mm No of Bolts Bolt Size UNC RF Stud Length ISO Stud Size
Class 900 Flange
1/2 15 4 3/4 110 M20
3/4 20 4 3/4 115 M20
1 25 4 7/8 125 M24
1 1/4 32 4 7/8 125 M24
1 1/2 40 4 1 140 M27
2 50 8 7/8 145 M24
2 1/2 65 8 1 160 M27
3 80 8 7/8 145 M24
4 100 8 1 1/8 170 M30
5 125 8 1 1/4 190 M33
6 150 12 1 1/8 190 M30
8 200 12 1 3/8 220 M36
10 250 16 1 3/8 235 M36
12 300 20 1 3/8 255 M36
14 350 20 1 1/2 275 M39
16 400 20 1 5/8 285 M42
18 450 20 1 7/8 325 M48
20 500 20 2 350 M52
24 600 20 2 1/2 440 M64

Unlock New Skills with Our Best Selling Online Courses

Principles, Operation and Design of Centrifugal Pump and Compressor - Training Courses
23% Discount

Pumps and Compressors Bundle

Learn Principles, Operation and Design of Centrifugal Pump and Compressor in this Course Bundle.

69.99

89.99

P&ID and Process Control Bundle - Training Courses
33% Discount

P&ID and Process Control Bundle

Learn about P&ID and Process Control of Process Plants in this Course Bundle.

79.99

119.99

Class 1500 Bolt and stud Charts

Size in Inch Size in mm No of Bolts Bolt Size UNC RF Stud Length ISO Stud Size
Class 1500 Flange
1/2 15 4 3/4 110 M20
3/4 20 4 3/4 115 M20
1 25 4 7/8 125 M24
1 1/4 32 4 7/8 125 M24
1 1/2 40 4 1 140 M27
2 50 8 7/8 145 M24
2 1/2 65 8 1 160 M27
3 80 8 1 1/8 180 M30
4 100 8 1 1/4 195 M33
5 125 8 1 1/2 250 M39
6 150 12 1 3/8 260 M36
8 200 12 1 5/8 290 M42
10 250 12 1 7/8 335 M48
12 300 16 2 375 M52
14 350 16 2 1/4 405 M56
16 400 16 2 1/2 445 M64
18 450 16 2 3/4 495 M72
20 500 16 3 540 M76
24 600 16 3 1/2 615 M90

Class 2500 Stud and Bolt Dimensions Charts

Size in Inch Size in mm No of Bolts Bolt Size UNC RF Stud Length ISO Stud Size
Class 2500 Flange
1/2 15 4 3/4 120 M20
3/4 20 4 3/4 125 M20
1 25 4 7/8 140 M24
1 1/4 32 4 1 150 M27
1 1/2 40 4 1 1/8 170 M30
2 50 8 1 180 M27
2 1/2 65 8 1 1/8 195 M30
3 80 8 1 1/4 220 M33
4 100 8 1 1/2 255 M39
5 125 8 1 3/4 300 M45
6 150 8 2 345 M52
8 200 12 2 380 M52
10 250 12 2 1/2 490 M64
12 300 12 2 3/4 540 M72

Are You Piping Components Master?

About Author

Varun Patel, B.E – Mechanical, PMP®

19+ years of experience in the oil and gas sector, specializing in project management, contracts, project control, project coordination, QA/QC and inspection of large-scale Greenfield and Brownfield Projects such as Refinery, Petrochemical, Wellhead production, and Process platform. Proven track record of delivering large-scale projects while ensuring adherence to safety and quality standards. Skilled in leading and mentoring cross-functional teams and resolving technical issues to achieve successful project outcomes.