Free tool · Instant answers
Gauge & Unit Converter
Turn gauge numbers into millimetres, feet into metres and square feet into square metres. Useful when a drawing, a quote and the site all use different units.
How to use it · 3 easy steps
- 1 Find the box for what you want to change: gauge, length, area, weight or pipe size.
- 2 Type your number in the unit you have.
- 3 Read the answer in the other boxes. It updates as you type.
Example: Your supplier says "18 gauge". Pick 18 in the gauge box and see it is about 1.2 mm thick.
1 · Sheet gauge → millimetres
Pick the gauge number. You get the thickness in mm for each gauge system.
| Gauge | Steel sheet | Galvanized | SWG |
|---|---|---|---|
| 8 | 4.18 mm | 4.27 mm | 4.06 mm |
| 10 | 3.42 mm | 3.51 mm | 3.25 mm |
| 12 | 2.66 mm | 2.75 mm | 2.64 mm |
| 14 | 1.90 mm | 1.99 mm | 2.03 mm |
| 16 | 1.52 mm | 1.61 mm | 1.63 mm |
| 18 | 1.21 mm | 1.31 mm | 1.22 mm |
| 20 | 0.91 mm | 1.01 mm | 0.91 mm |
| 22 | 0.76 mm | 0.85 mm | 0.71 mm |
| 24 | 0.61 mm | 0.70 mm | 0.56 mm |
| 26 | 0.46 mm | 0.55 mm | 0.46 mm |
| 28 | 0.38 mm | 0.47 mm | 0.38 mm |
| 30 | 0.30 mm | 0.40 mm | 0.32 mm |
2 · Length
Type in any box. The others change by themselves.
3 · Area
For roofs, walls, plots and sheets.
4 · Weight
Steel is often quoted per kilogram or per tonne.
5 · Pipe size in inches → millimetres
Pipes are named in inches (nominal bore, "NB") but measured in mm. Click a size to highlight it.
Gauge values: steel sheet from the Manufacturers' Standard Gauge, galvanized sheet from the galvanized sheet gauge, SWG from the British Standard Wire Gauge. Always confirm the thickness in mm on your order.
Questions
Converter FAQ
More free tools: Steel Weight Calculator, Material List Builder and Measurement Calculator.
How many mm is 18 gauge steel?
18 gauge steel sheet is about 1.21 mm thick (Manufacturers’ Standard Gauge). 18 gauge galvanized sheet is about 1.31 mm, and 18 SWG is 1.219 mm.
How thick is 24 gauge sheet?
A 24 gauge steel sheet is about 0.61 mm thick, and 24 gauge galvanized sheet about 0.70 mm. Roofing sheets in the UAE are usually described directly in millimetres, such as 0.5 mm.
Why does the same gauge give different thicknesses?
There are several gauge systems. Plain steel sheet, galvanized sheet and wire each have their own table, so always confirm the thickness in millimetres before ordering.
How many square feet are in one square metre?
One square metre equals 10.764 square feet. To change square feet into square metres, divide by 10.764.
What is the outside diameter of a 2 inch pipe?
A 2" nominal bore (NB) steel pipe has an outside diameter of 60.3 mm. A 1" pipe is 33.7 mm and a 4" pipe is 114.3 mm.