MM to SWG Conversion Calculator

MM to SWG Calculator

Our millimeter to standard wire gauge mm to swg calculator is designed to convert measurements between millimeters and gauge wire system.

The SWG system, established in the 1880s, remains widely used in the UK and several Commonwealth nations. It assigns numerical values ranging from 0000 (largest) to 50 (smallest), with each number representing a specific wire diameter.

A copper wire measuring 2.64 mm in diameter with MM to SWG conversion:

Input: 2.64 mm
Output: 12 SWG

MM to SWG Conversion Table

Millimeters (mm)	Formula Calculation	SWG Result
0.5 mm	17.0 – (7.44 × ln(0.5))	24 SWG
0.6 mm	17.0 – (7.44 × ln(0.6))	23 SWG
0.7 mm	17.0 – (7.44 × ln(0.7))	22 SWG
0.8 mm	17.0 – (7.44 × ln(0.8))	21 SWG
0.9 mm	17.0 – (7.44 × ln(0.9))	20 SWG
1.0 mm	17.0 – (7.44 × ln(1.0))	19 SWG
1.2 mm	17.0 – (7.44 × ln(1.2))	18 SWG
1.5 mm	17.0 – (7.44 × ln(1.5))	17 SWG
1.8 mm	17.0 – (7.44 × ln(1.8))	16 SWG
2.0 mm	17.0 – (7.44 × ln(2.0))	14 SWG
2.5 mm	17.0 – (7.44 × ln(2.5))	13 SWG
3.0 mm	17.0 – (7.44 × ln(3.0))	11 SWG
3.5 mm	17.0 – (7.44 × ln(3.5))	10 SWG
4.0 mm	17.0 – (7.44 × ln(4.0))	9 SWG
4.5 mm	17.0 – (7.44 × ln(4.5))	8 SWG
5.0 mm	17.0 – (7.44 × ln(5.0))	7 SWG
6.0 mm	17.0 – (7.44 × ln(6.0))	6 SWG
8.0 mm	17.0 – (7.44 × ln(8.0))	4 SWG
10 mm	17.0 – (7.44 × ln(10))	3 SWG
12 mm	17.0 – (7.44 × ln(12))	2 SWG

MM to SWG Conversion Formula

SWG = f(mm) ≈ 17.0 - (7.44 × ln(mm))

Where:

f(mm) is the function converting millimeters to SWG
ln is the natural logarithm
mm is the measurement in millimeters

For 2.64 mm:
SWG = 17.0 - (7.44 × ln(2.64))
    = 17.0 - (7.44 × 0.97)
    = 17.0 - 7.22
    ≈ 12 SWG

How to Convert MM to SWG

Converting millimeters to SWG involves these steps:

Measure the wire diameter in millimeters using a calibrated micrometer.
Consult the conversion chart or use the formula.
Round to the nearest whole SWG number.
Verify the conversion using standard tables.

Converting 3.25 mm to SWG:

Initial measurement: 3.25 mm
Apply formula: 17.0 - (7.44 × ln(3.25))
Result: 10.2
Round to nearest whole number: 10 SWG

0.8 mm in SWG

Using the formula:

SWG = 17.0 - (7.44 × ln(0.8))
    ≈ 21 SWG

1.5 mm to SWG