Allen Wrench Size Chart
Allen wrench size chart explained below consists of the hex size, suitable long arm length and also short arm length. It is designed to help you in the workshop and use a proper Allen wrench when needed. Keep in mind that wrenches made from stainless steel won’t corrode or rust regardless of how and where they are used. This material is immune to rusk completely. This is important due to the fact the wrench will always maintain its size.
The tables below are basically identical but available in different measurements. The first one is millimeters or metric while the second is in inches, imperial size chart. The third table is related to more specific Allen keys and it shows the correlation between the hex size in inches and the long/short arm ibn millimeters. The first two charts refer to stainless steel models. The third is based for different materials and for models with the round head (used to make insertion much easier). See also digital torque wrench review.
Stainless Allen Keys Metric
| Hex size | Long arm lenght | Short arm lenght |
|---|---|---|
| 1.5 mm | 90 mm | 14 mm |
| 2 mm | 112 mm | 19 mm |
| 2.5 mm | 101 mm | 16 mm |
| 3 mm | 123 mm | 21 mm |
| 4 mm | 137 mm | 24 mm |
| 5 mm | 154 mm | 27 mm |
| 6 mm | 172 mm | 31 mm |
| 8 mm | 195 mm | 37 mm |
| 10 mm | 224 mm | 42 mm |
Stainless Allen Keys Imperial
| Hex size | Long arm lenght | Short arm lenght |
|---|---|---|
| 3/32 inch | 112 mm | 19 mm |
| 7/64 inch | 119 mm | 20 mm |
| 1/8 inch | 123 mm | 21 mm |
| 9/64 inch | 130 mm | 22 mm |
| 5/32 inch | 137 mm | 24 mm |
| 3/16 inch | 154 mm | 27 mm |
| 1/4 inch | 185 mm | 34 mm |
| 5/16 inch | 195 mm | 37 mm |
| 3/8 inch | 224 mm | 42 mm |
Allen Keys Imperial
| Hex size | Long arm lenght | Short arm lenght |
|---|---|---|
| 0.05 inch | 83 mm | 14 mm |
| 1/16 inch | 91 mm | 15 mm |
| 5/64 inch | 100 mm | 16 mm |
| 3/32 inch | 112 mm | 18 mm |
| 7/64 inch | 119 mm | 19 mm |
| 1/8 inch | 126 mm | 20 mm |
| 9/64 inch | 132 mm | 23 mm |
| 5/32 inch | 140 mm | 25 mm |
| 3/16 inch | 160 mm | 25 mm |
| 7/32 inch | 180 mm | 27 mm |
| 1/4 inch | 190 mm | 34 mm |
| 5/16 inch | 200 mm | 36 mm |
| 1/2 inch | 224 mm | 40 mm |
Here is a trick when using an Allen Wrench you might not have known about:
