| Short Arm SAE Allen Wrench Dimensions (Hex Key) | ||||
|---|---|---|---|---|
|
Hex Allen Key Sizes Click on the size to shop products |
Width Across Flats | Length of Long Arm | Length of Short Arm | |
| Max | Min | |||
| 0.028" | 0.028" | 0.0275" | 1.219" | 0.219" |
| 0.035" | 0.035" | 0.0345" | 1.219" | 0.344" |
| 0.050" | 0.050" | 0.049" | 1.656" | 0.531" |
| 1/16" | 0.0625" | 0.0615" | 1.75" | 0.562" |
| 5/64" | 0.0781" | 0.0771" | 1.875" | 0.609" |
| 3/32" | 0.0937" | 0.0927" | 2" | 0.656" |
| 7/64" | 0.1093" | 0.1077" | 2.125" | 0.703" |
| 1/8" | 0.1250" | 0.1235" | 2.25" | 0.75" |
| 9/64" | 0.1406" | 0.1391" | 2.375" | 0.796" |
| 5/32" | 0.1562" | 0.1547" | 2.5" | 0.844" |
| 3/16" | 0.1875" | 0.1860" | 2.75" | 0.938" |
| 7/32" | 0.2187" | 0.2172" | 3" | 1.031" |
| 1/4" | 0.250" | 0.248" | 3.25" | 1.125" |
| 5/16" | 0.3125" | 0.3110" | 3.75" | 1.25" |
| 3/8" | 0.375" | 0.373" | 4.25" | 1.375" |
| 7/16" | 0.4375" | 0.4355" | 4.75" | 1.5" |
| 1/2" | 0.50" | 0.04975" | 5.25" | 1.625" |
| 9/16" | 0.5625" | 0.56" | 5.75" | 1.75" |
| 5/8" | 0.625" | 0.6225" | 6.25" | 1.875" |
| 3/4" | 0.75" | 0.747" | 7.25" | 2.125" |
| 7/8" | 0.875" | 0.872" | 8.25" | 2.375" |
| 1" | 0.050" | 0.049" | 1.656" | 0.531" |
* Additional Imperial sizes are available on our website.
| Short Arm Metric Allen Wrench Dimensions (Hex Key) | ||||||
|---|---|---|---|---|---|---|
|
Hex Allen Key Sizes Click on the size to shop products |
Width Across Flats | Length of Long Arm | Length of Short Arm | |||
| Max | Min | Max | Min | Max | Min | |
| 0.9 | 0.899 | 0.876 | 34 | 28 | 11 | 6 |
| 1.3 | 1.270 | 1.244 | 44 | 39 | 16 | 11 |
| 1.5 | 1.5 | 1.47 | 45 | 43 | 14 | 13 |
| 2 | 2.00 | 1.97 | 50 | 48 | 16 | 15 |
| 2.5 | 2.50 | 2.47 | 56 | 53 | 18 | 17 |
| 3 | 3.00 | 2.96 | 63 | 60 | 20 | 18 |
| 4 | 4.00 | 3.96 | 70 | 66 | 25 | 23 |
| 5 | 5.00 | 4.96 | 80 | 76 | 28 | 26 |
| 6 | 6.00 | 5.95 | 90 | 86 | 32 | 30 |
| 8 | 8.00 | 7.95 | 100 | 95 | 36 | 34 |
| 10 | 10.00 | 9.95 | 102 | 106 | 40 | 38 |
| 12 | 12.00 | 11.95 | 125 | 119 | 45 | 43 |
| 14 | 14.00 | 13.95 | 140 | 133 | 56 | 53 |
| 17 | 17.00 | 16.93 | 160 | 152 | 63 | 60 |
| 19 | 19.00 | 18.93 | 280 | 271 | 70 | 67 |
* Additional Metric sizes are available on our website.
| Long Arm SAE Hex Key Dimensions (Hex Key) | ||||
|---|---|---|---|---|
|
Hex Allen Key Sizes Click on the size to shop products |
Width Across Flats | Length of Long Arm | Length of Short Arm | |
| Max | Min | |||
| 0.050" | 0.050" | 0.049" | 2.844" | 0.531" |
| 1/16" | 0.0625" | 0.0615" | 3" | 0.562" |
| 5/64" | 0.0781" | 0.0771" | 3.188" | 0.609" |
| 3/32" | 0.0937" | 0.0927" | 3.375" | 0.656" |
| 7/64" | 0.1093" | 0.1077" | 3.562" | 0.703" |
| 1/8" | 0.1250" | 0.1235" | 3.75" | 0.75" |
| 9/64" | 0.1406" | 0.1391" | 3.937" | 0.796" |
| 5/32" | 0.1562" | 0.1547" | 4.125" | 0.844" |
| 3/16" | 0.1875" | 0.1860" | 4.5" | 0.938" |
| 7/32" | 0.2187" | 0.2172" | 4.875" | 1.031" |
| 1/4" | 0.250" | 0.248" | 5.25" | 1.125" |
| 5/16" | 0.3125" | 0.3110" | 6" | 1.25" |
| 3/8" | 0.375" | 0.373" | 6.75" | 1.375" |
| 7/16" | 0.4375" | 0.4355" | 7.5" | 1.5" |
| 1/2" | 0.50" | 0.04975" | 8.25" | 1.625" |
| 9/16" | 0.5625" | 0.56" | 9" | 1.75" |
| 5/8" | 0.625" | 0.6225" | 9.75" | 1.875" |
| 3/4" | 0.75" | 0.747" | 11.25" | 2.125" |
| 7/8" | 0.875" | 0.872" | 12.75" | 2.375" |
| 1" | 0.050" | 0.049" | 14.25" | 0.531" |
* Additional Metric sizes are available on our website.
| Long Arm Metric Allen Wrench Dimensions (Hex Key) | ||||||
|---|---|---|---|---|---|---|
|
Hex Allen Key Sizes Click on the size to shop products |
Width Across Flats | Length of Long Arm | Length of Short Arm | |||
| Max | Min | Max | Min | Max | Min | |
| 1.5 | 1.5 | 1.47 | 78 | 76 | 14 | 13 |
| 2 | 2.00 | 1.97 | 83 | 81 | 16 | 15 |
| 2.5 | 2.50 | 2.47 | 90 | 87 | 18 | 17 |
| 3 | 3.00 | 2.96 | 100 | 97 | 20 | 18 |
| 4 | 4.00 | 3.96 | 106 | 102 | 25 | 23 |
| 5 | 5.00 | 4.96 | 118 | 114 | 28 | 26 |
| 6 | 6.00 | 5.95 | 140 | 136 | 32 | 30 |
| 7 | 7.00 | 6.97 | 145 | 140 | 36 | 34 |
| 8 | 8.00 | 7.95 | 160 | 155 | 36 | 34 |
| 10 | 10.00 | 9.95 | 170 | 164 | 40 | 38 |
* Additional Metric sizes are available on our website.
| Torx/Star Tamper Proof L Key Dimensions | ||
|---|---|---|
|
Drive Size Click on the size to shop products |
Length of Short Arm | Length of Long Arm |
| T-6 | 0.5" | 1.65" |
| T-7 | 0.55" | 1.75" |
| T-8 | 0.6" | 1.85" |
| T-9 | 0.65" | 2" |
| T-10 | 0.7" | 2.1" |
| T-15 | 0.75" | 2.2" |
| T-20 | 0.8" | 2.35" |
| T-25 | 0.85" | 2.5" |
| T-27 | 0.95" | 2.75" |
| T-30 | 1.05" | 3" |
| T-45 | 1.25" | 3.75" |
| T-50 | 1.35" | 4.25" |
| T-55 | 1.5" | 4.75" |
Allen Wrench / Hex Key Conversions
The chart below offers the best substitute for popular allen wrench sizes from both Imperial to Metric and Metric to Imperial. Be aware that using a smaller size key will increase the chance of stripping the hardware. For some applications, you may want to try using a larger size key than the one recommended in the chart to see if it fits. When substituting sizes, there isn't always a perfect counterpart and it's best to have both Metric and Imperial allen wrench sets available.
| Hex Key / Allen Wrench Conversion Chart | |||
|---|---|---|---|
| SAE Conversion for MM |
MM Conversion for SAE | ||
| 5/64" | 2 mm | 2 mm | 3/32" |
| 3/32" | 2.5 mm | 2.5 mm | 7/64" |
| 7/64" | 3 mm | 3 mm | 1/8" |
| 1/8" | 3.5 mm | 3.5 mm | 9/64" |
| 5/32" | 4 mm | 4 mm | 5/32" |
| 3/16" | 5 mm | 5.5 mm | 7/32" |
| 7/32" | 5.5 mm & 6 mm | 6 mm | 1/4" |
| 1/4" | 7 mm | 7 mm | 9/32" |
| 5/16" | 8 mm | 8 mm | 5/16" |
| 3/8" | 10 mm | 9 mm | 3/8" |
Frequently Asked Questions
Q: What is an Allen Wrench used for?
A: An Allen wrench is a tool that's used for installing and removing socket or hex head fasteners, such as set screws and socket head cap screws. They are usually L-shaped, however there are other styles available.
Q: Is an Allen wrench the same as a hex key?
A: Yes, an Allen wrench is the same as a hex key. They are also called L-Keys, L-Wrenches, Allen Keys
Q: Why are they called Allen Wrenches?
A: In 1909-1910, William G. Allen patented a method of cold-forming screw heads around a hexagonal die. The first trademarked hex key in the US was made by Allen Manufacturing and the name has been used ever since.
Q: Are Allen wrenches the same as Torx wrenches?
A: No, allen wrenches have a hexagon shape while Torx wrenches have a star shape.
Q: What are the types of Allen wrenches?
A: L-shaped, T-handle, P-handle, folding hex, ratcheting hex, torque wrench, Allen screwdriver, ball hex
Additional Resources
