Common Steel Plate Thicknesses
Engineering drawings often specify plate thickness in fractions (e.g., 3/8″). Use this reference table to find the exact decimal and metric (mm) equivalents.
The Formula
Inch = Millimeters ÷ 25.4
| Fraction | Decimal | Metric (mm) |
|---|---|---|
| 1/8″ | 0.1250 | 3.18 mm |
| 1/4″ | 0.2500 | 6.35 mm |
| 3/8″ | 0.3750 | 9.53 mm |
| 1/2″ | 0.5000 | 12.70 mm |
| 3/4″ | 0.7500 | 19.05 mm |
| 1″ | 1.0000 | 25.40 mm |
Frequently Asked Questions
+ What is the exact conversion factor?
1 Inch is exactly defined as 25.4 millimeters. To go from mm to inches, divide by 25.4. To go from inches to mm, multiply by 25.4.
+ Do you stock imperial thickness plates?
Yes, our inventory includes plates in standard inch increments (e.g., 0.5″, 1.0″, 2.0″) as well as standard metric thicknesses.
+ What is gauge thickness?
Gauge is an older system for thinner sheets (e.g., 10 Gauge ≈ 3.4mm). For heavy industry and structural steel, we primarily work with direct mm or inch measurements.
Note: For pipe schedules or non-standard dimensions, please contact our sales team.
