Torx to Allen Wrench Conversion Key

Torx to Allen Wrench Conversions

Torx to Hex Conversions Allen Wrench Key



Torx to Allen Key Conversions

We actually don’t recommend using your torx wrenches in place of a hex key or Allen wrench. However, rogue DIYers seem to think that it’s a good idea and insist on knowing the conversions. So by popular demand, we’ve created one of the first torx to hex conversion charts. From T7 to T40, we’ve provided the hex sizes that best match the most common torx sizes. Since most of our readers live in the United States, we opted to make the trox to Allen key conversions in terms of imperial sizes. With that being said, torx size, T9, won’t doesn’t really work with any of the SAE hex sizes. However, it’s actually a perfect match for metric size, 2.5 mm.

Why Torx Wrenches Are Poor Substitutes for Allen Wrenches

The short answer is…you’ll break your torx wrenches on a hex screw head. The fragile tips of a torx or security star bit are prone to bending & snapping without fitting snugly inside of the screw head. Given that the inside of a hex screw only provides a single contact point for each branch in the star, the torx tips will likely bend in the opposite direction. Also, it’s no secret that using an inappropriate bit will increase the the possible of of stripping the screw. When fastening a screw into place, we always recommend using the correct bit type & size. You’ll find that this practice will make your tools last longer. Furthermore, you’re hardware will break less frequently.

Breaking Down Each Torx to Hex Conversion

Torx Size Allen Wrench Conversion
T7 5/64″
T8 3/32″
T9 2.5 mm
T10 7/64″
T15 1/8″
T20 5/32″
T25 3/16″
T27 5 mm
T30 7/32″
T40 9/32″
Beginning with the smallest torx size on our list, T7 is actually a perfect fit for a 2mm hex. As for the imperial measurement system, T7 is just shy 5/64″. Moving on to T8, this torx size doesn’t have a metric counterpart. This isn’t uncommon at the smaller torx sizes as they are offer more precise than similarly sized hex keys. In the situation with T8, it will work in place of hex size, 7/32″. Similarly, T9 doesn’t have a counterpart on the imperial side. But for metric, it’s a perfect match for 2.5 mm. T10 converts perfection over to a 7/64″ hex size. However, it joins the pack of torx wrenches without a metric hex size.

Jumping up to T15, it’s basically the same size as 1/8″ hex. Likewise, you’ll find that T20 is more-or-less equal to 5/32″. For T25, we finally get another torx size with both SAE & metric equivalents. Either 3/16″ or 4.5 mm will accept T25. In regards to torx size, T27, it fits closely inside of hex size 5 mm. Unlike it’s preceding size, T27 doesn’t really have an SAE substitute.

With the larger torx sizes, the hex counterparts become less straight forward. Since the torx wrenches start increasing in size a large increments, they often fall between to hex sizes. For instance, T30 matches up fairly well with 7/32″, and even 1/4″. However, it is a bit too large for 5.5 mm hex (still recommend that you try). For T40, you’re only option on the hex side is 9/32″. Unfortunately, T40 is a bit to large to be a substitute for 1/4″ or 6.5 mm hex sizes.




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