Leather varies widely in thickness, both between hides and within single hides. Especially for large pieces, such as sides and whole hides, thickness will often be stated as a range, such as “6-8 ounce” or “10/12 iron”, approximating the thinnest to thickest portions of the piece overall.
Leather sellers measure thickness in various ways.
Comparison Table
| Ounces | Irons | Fractional Inches | Decimal Inches | Millimeters |
|---|---|---|---|---|
| 1 oz | ¾ iron | 1/64″ | 0.015625″ | 0.396875 mm |
| 0.5 mm | ||||
| 1 iron | 1/48″ | 0.02083″ | 0.52916 mm | |
| 2 oz | 1½ iron | 1/32″ | 0.03125″ | 0.79375 mm |
| 1 mm | ||||
| 2 iron | 1/24″ | 0.0416″ | 1.0583 mm | |
| 3 oz | 1/64″ | 0.046875″ | 1.190625 mm | |
| 1.5 mm | ||||
| 4 oz | 3 iron | 1/16″ | 0.0625″ | 1.5875 mm |
| 5 oz | 3¾ iron | 1/64″ | 0.078125″ | 1.984375 mm |
| 2 mm | ||||
| 4 iron | 1/12″ | 0.083″ | 2.116 mm | |
| 6 oz | 4½ iron | 1/32″ | 0.09375″ | 2.38125 mm |
| 2.5 mm | ||||
| 5 iron | 1/48″ | 0.10416″ | 2.64583 mm | |
| 7 oz | 5¼ iron | 1/64″ | 0.109375″ | 2.778125 mm |
| 3 mm | ||||
| 8 oz | 6 iron | 1/8″ | 0.125″ | 3.175 mm |
| 3.5 mm | ||||
| 9 oz | 6¾ iron | 1/64″ | 0.140625″ | 3.571875 mm |
| 7 iron | 1/48″ | 0.14583″ | 3.70416 mm | |
| 10 oz | 7½ iron | 1/32″ | 0.15625″ | 3.96875 mm |
| 4 mm | ||||
| 8 iron | 1/6″ | 0.16″ | 4.23 mm | |
| 11 oz | 8¼ iron | 1/64″ | 0.171875″ | 4.365625 mm |
| 4.5 mm | ||||
| 12 oz | 9 iron | 1/16″ | 0.1875″ | 4.7625 mm |
| 5 mm | ||||
| 13 oz | 9¾ iron | 1/64″ | 0.203125″ | 5.159375 mm |
| 10 iron | 1/24″ | 0.2083″ | 5.2916 mm | |
| 5.5 mm | ||||
| 14 oz | 10½ iron | 1/32″ | 0.21875″ | 5.55625 mm |
| 11 iron | 1/48″ | 0.22916″ | 5.82083 mm | |
| 15 oz | 11¼ iron | 1/64″ | 0.234375″ | 5.953125 mm |
| 6 mm | ||||
| 16 oz | 12 iron | 1/4″ | 0.25″ | 6.35 mm |
| 13 iron | 1/48″ | 0.27083″ | 6.87916 mm | |
| 7 mm | ||||
| 14 iron | 1/24″ | 0.2916″ | 7.4083 mm |