Unit Conversion Reference
Area base (m²): mm²=0.000001, ft²=0.0929, yd²=0.8361, acres=4046.86, ha=10000
Volume base (L): mL=0.001, m³=1000, ft³=28.3168, yd³=764.555, gal(AU)=4.546
Weight base (kg): g=0.001, tonnes=1000, lbs=0.4536, oz=0.02835
Note: Gallons use Australian/Imperial measure (4.546 L). US gallons differ (3.785 L).
Unit Converter — Construction Unit Conversions
Australian construction uses metric, but builders regularly encounter imperial measurements in imported materials and older buildings. This converter handles length, area, volume, weight, and pressure conversions.
Common Conversions
| From | To | Multiply By |
|---|---|---|
| Inches | Millimetres | 25.4 |
| Feet | Metres | 0.3048 |
| Square feet | Square metres | 0.0929 |
| Cubic yards | Cubic metres | 0.7646 |
| Pounds (lb) | Kilograms | 0.4536 |
| PSI | MPa | 0.006895 |
Timber Size Conversions (Imperial to Metric)
| Imperial | Actual | AU Metric |
|---|---|---|
| 2×4 | 38×89mm | ~90×35 |
| 2×6 | 38×140mm | ~140×35 |
| 2×8 | 38×184mm | ~190×35 |
| 4×4 | 89×89mm | ~90×90 |
Frequently Asked Questions
How to convert feet to metres?
Multiply feet by 0.3048. 10 feet = 3.048 metres.
What is a 2×4 in metric?
Actually 38×89mm. Closest Australian equivalent is 90×35mm.
PSI to MPa for concrete?
Divide by 145.04. 4,000 PSI = 27.6 MPa (~N32 concrete).
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Gauge to mm Conversion Chart (Australian Standard)
Sheet metal and wire gauges in Australia follow the AWG/SWG standards used internationally. Use the table below for quick reference, or the unit converter above for arbitrary conversions.
Common Gauge to Millimetre Conversions
| Gauge | mm (Steel SWG) | mm (Aluminium AWG) | Common Use |
|---|---|---|---|
| 10 gauge | 3.25mm | 2.59mm | Heavy steel sheet, machinery |
| 12 gauge | 2.64mm | 2.05mm | Roofing, structural sheet |
| 14 gauge | 2.03mm | 1.63mm | Light structural, ductwork |
| 16 gauge | 1.63mm | 1.29mm | Studs, fascia, gutters |
| 18 gauge | 1.22mm | 1.02mm | Light ducting, flashing |
| 20 gauge | 0.91mm | 0.81mm | Light gauge profiles |
| 22 gauge | 0.71mm | 0.64mm | Sheet metal, light flashing |
| 24 gauge | 0.56mm | 0.51mm | Roofing flashings, ducting |
Quick Conversion Formulas
- SWG (Standard Wire Gauge) — used for steel sheet in Australia. The higher the number, the thinner the metal.
- AWG (American Wire Gauge) — used for aluminium and electrical wire. AWG = -39 × log10(diameter_mm / 0.127)
- BWG (Birmingham Wire Gauge) — used for some structural steel applications.
Australian Sheet Metal Standards
Australian sheet metal sold for roofing, gutters, and structural applications generally follows BS 3382 (steel) or AS 1734 (aluminium). For roofing in particular, COLORBOND® and ZINCALUME® steel are sold in BMT (Base Metal Thickness) measurements rather than gauge — common BMT values are 0.42mm, 0.48mm, and 0.55mm.