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3/8 inch nut size
9/16 in wrench
across-flats spanner / socket size for 3/8 in nut
3/8 inch nut — pairs with 3/8-16 bolts.
Full specification
| System | Imperial |
| Nominal diameter | 3/8 in thread |
| Thread pitch | 16 TPI |
| Wrench / spanner (across flats) | 9/16 in |
| Tap drill | n/a |
| Clearance hole | n/a |
| Common grade / class | matches bolt |
| Typical torque | 47 Nm (35 ft·lb) |
| Closest other-system size | ~M10 nut |
🔧 Torque unit converter
Pre-filled with the typical torque for 3/8 in nut (matches bolt, dry). Edit any field to convert.
⚠️ Torque values here are general references for matches bolt on clean, dry threads. Lubrication, coatings, and the joint material change the figure significantly. For structural, automotive, or safety-critical work, always use the torque specified by the manufacturer or engineer.
About 3/8 in nut
A 3/8-16 hex nut uses a 9/16 in wrench across the flats.
A 9/16 in wrench fits both the 3/8 in bolt head and its nut.
Frequently asked questions
- What size wrench or spanner fits 3/8 in nut?
- 3/8 inch nut uses a 9/16 in wrench or spanner, measured across the flats of the hex head.
- What is the torque for 3/8 in nut?
- A typical tightening torque for 3/8 inch nut in matches bolt on dry threads is about 47 Nm (35 ft·lb). Always confirm against the manufacturer spec for important joints.
- What thread pitch and tap drill does 3/8 in nut use?
- 3/8 inch nut has a thread pitch of 16 TPI and uses a n/a tap drill, with a n/a clearance hole.