Wire Diameter (mm) Enter the wire thickness in millimeters (range: 0.05 - 12.7 mm)

Quick Examples:

Medium Wire (SWG 14) Thin Wire (SWG 22)

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This calculator is for informational purposes only. Verify results with appropriate professionals for important decisions. SWG standards may vary slightly by manufacturer.

What Is Standard Wire Gauge

Standard Wire Gauge (SWG) is a set of wire sizes used to measure the thickness of wire. It is also known as the British Standard Wire Gauge. The gauge number works in a special way: a smaller number means a thicker wire, and a larger number means a thinner wire. This system helps people buy the right wire for electrical work or crafts.

How Standard Wire Gauge Is Calculated

Formula

The calculation does not use a math problem like addition or multiplication. Instead, it uses a lookup table. First, the tool looks at the size you entered. Then, it compares your size to a fixed list of standard sizes for every SWG number from 0 to 40. It finds the standard size that is numerically closest to your measurement and reports that SWG number.

Why Standard Wire Gauge Matters

Knowing the correct SWG is important for safety and fit. If a wire is too thick for a terminal or connector, it will not fit. If it is too thin, it may not carry enough electricity safely or may break easily.

Why Correct Gauge Is Important for Electrical Safety

Using the correct wire gauge helps prevent wires from getting too hot. Wires that are too thin for the amount of current flowing through them can overheat. This heat may damage the insulation or cause a fire. Always check the correct gauge for the electrical load.

For Electrical Connections

In electrical work, matching the SWG ensures a tight connection in screws and terminals. A loose connection can cause sparks or high resistance. You may consider using a wire gauge tool to measure physically before buying.

For Manufacturing and Craftsmanship

In manufacturing and jewelry making, precise wire size ensures parts fit together. If a wire must pass through a small hole, the gauge must be exact. Differences of even a fraction of a millimeter can ruin a part. You may consider verifying the size with calipers for precision work.