Roymech engineering encyclopedia

Standard Wire Gauge (SWG) Chart – Sizes, mm Conversion and Mesh Equivalents




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Standard Wire Gauge (SWG) is a British system used to define wire diameter and thickness. It is widely used in engineering, manufacturing and material processing applications.

This page provides a complete SWG chart with metric (mm) conversions, along with mesh size equivalents used in screening, filtration and particle size analysis.

The SWG system is based on a progression where the gauge numbers decrease as the wire diameter increases. The standard wire gauge sizes range from the thinnest wire, SWG 7/0 (0.5 mm diameter), to the thickest wire, SWG 50 (5.59 mm diameter).

See also related engineering data including stress and strain equations, welding symbols and coefficient of friction tables.

Standard Wire Gauge (SWG) Explained

Standard Wire Gauge (SWG) is a system where smaller gauge numbers represent thicker wires. For example, SWG 10 is thicker than SWG 20. The system is commonly used in the UK and is defined by standard tables rather than a formula.

SWG Wire Gauge Conversion Table (mm and inches)

The table below shows Standard Wire Gauge sizes with corresponding diameters in millimetres and inches for engineering reference.

SWG inch x103 mm -  SWG inch x103 mm   SWG inch x103 mm  
7/0 500 12.7   13 92 2.34   33 10.0 0.254  
6/0 464 11.8   14 80 2.03   34 9.2 0.234  
5/0 432 11.0   15 72 1.83   35 8.4 0.213  
4/0 400 10.2   16 64 1.63   36 7.6 0.193  
3/0 372 9.45   17 56 1.42   37 6.8 0.173  
        18 48 1.22   38 6.0 0.152  
00 348 8.84   19 40 1.02   39 5.2 0.132  
0 324 8.23   20 36 0.914   40 4.8 0.122  
1 300 7.62   21 32 0.813   41 4.4 0.112  
2 276 7.01   22 28 0.711   42 4.0 0.102  
3 252 6.40   23 24 0.610   43 3.6 0.091  
4 232 5.89   24 22 0.559   44 3.2 0.081  
5 212 5.38   25 20 0.508   45 2.8 0.071  
6 192 4.88   26 18 0.457   46 2.4 0.061  
7 176 4.47   27 16.4 0.417   47 2.0 0.051  
8 160 4.06   28 14.8 0.376   48 1.6 0.041  
9 144 3.66   29 13.6 0.345   49 1.2 0.030  
10 128 3.25   30 12.4 0.315   50 1.0 0.025  
11 116 2.95   31 11.6 0.295     - -  
12 104 2.64   32 10.8 0.274     - -  


Metric Mesh Sizes

BS 410-1:2000 has now been replaced by BS ISO 3310-1:2016

DIN 4188-1:1977‑10 was the original German standard defining screening surfaces — specifically, wire cloth test sieves, including their dimensions, has now been replaced by DIN ISO 3310-1:2009

Mesh Size Chart (Microns, mm and Mesh Number)

Mesh size defines the number of openings per inch in a sieve and is used in material classification, filtration and screening applications.

Aperture Size BS 410-1
:2000		 DIN-4188   Aperture Size BS 410-1
:2000		 DIN-4188   Aperture Size BS 410-1
:2000		 DIN-4188
m (microns) Mesh mm   m (microns) Mesh mm   m (microns) Mesh mm
                     
5 2500 0.005   106 150     600 25  
10 1250 0.01   112   0.112   630   0.63
15 800 0.015   115   0.115   710 22 0.71
                     
20 625 0.02   125 120 0.125   800   0.8
22   0.022   140   0.14   850 18  
25 500 0.025   150 100     900   0.9
                     
28   0.028   160   0.16   1000 16 1
32   0.032   180 85 0.18   1120   1.12
36   0.036   200   0.2   1180 14  
                     
38 400     212 72     1250   1.25
40   0.04   250 60 0.25   1400 12 1.4
45 350 0.045   280   0.28   1600   1.6
                     
50   0.05   300 52     1700 10  
53 300     315   0.315   1800   1.8
56   0.056   355 44 0.355   2000 8 2
                     
63 240 0.063   400   0.4   2240   2.24
71   0.071   425 36     2360 7  
75 200     450   0.45   2500   2.5
                     
80   0.08   500 30 0.5   2800 6 2.8
90 170 0.09   560   0.56   3150   3.15
100   0.1   600 25     3350 5  
                     

Applications of Wire Gauge and Mesh Sizes

  • Wire selection for electrical and mechanical applications
  • Manufacturing and fabrication processes
  • Material screening and particle size analysis
  • Filtration and sieve design
  • Quality control in industrial processes

Advantages of Standard Wire Gauge (SWG)

  • Widely recognised and standardised system
  • Provides quick reference for wire thickness
  • Compatible with imperial and metric conversions
  • Useful across multiple engineering disciplines
  • Simplifies specification and ordering

Limitations of SWG and Mesh Systems

  • Not universally used outside UK-based standards
  • Can cause confusion with other gauge systems (AWG)
  • Mesh size does not directly define wire diameter
  • Requires conversion for metric-only applications
  • Tables needed for accurate interpretation

Frequently Asked Questions

What does SWG stand for?

SWG stands for Standard Wire Gauge, a British system for measuring wire diameter.

Is SWG the same as AWG?

No, SWG and AWG are different systems with different size values.

What is mesh size?

Mesh size refers to the number of openings per inch in a screen or sieve.

How do you convert SWG to mm?

You use standard conversion tables that list gauge numbers alongside metric diameters.

What are mesh sizes used for?

They are used in sieving, filtration, and particle size classification.





    Links to other sources of wire gauge equivalents/mesh sizes
    1. Efunda .. Design Center includes Wire gauge calculators
    2. Fine Mesh Metals .. Mesh Suppliers
    3. F.H Brundle .. Mesh suppliers useful relevant information