Quick-reference torque values for M3 bolts across all property classes. Values shown for dry/plain steel, coarse thread. Click any card for full details including all surface conditions.
These values assume dry/plain steel (K = 0.20) and coarse thread. Oiled, zinc-plated, or lubricated bolts require different torque. See full details →
For a typical M3 class 8.8 bolt the dry figure is 1.31 N·m (0.97 ft·lbs). If the threads are oiled, drop to 0.98 N·m — using the dry number on an oiled bolt would push it about 34% past the intended clamp load. Class 10.9 takes 1.88 N·m, 44% more than 8.8, and the fine M3×0.35 thread raises the 8.8 figure to 1.46 N·m because its stress area is 12% larger.
Small sizes like M3 are mostly machine screws in electronics, sheet-metal assemblies, covers and light brackets. The torque figures are low enough that a click-type 3/8" wrench is at the bottom of its range or below it — use a 1/4" drive wrench or a torque screwdriver, and read the in·lbs column on the detail pages. Stripping the female thread is the usual failure at this size, especially in aluminium or plastic bosses, so the property-class figure is an upper limit when the mating part is weaker than the bolt.
N·m. Coarse thread unless noted. Clamp load is the 75%-of-proof preload the torque is sized to produce.
| Coarse thread | M3×0.5 |
| Fine thread | M3×0.35 |
| Stress area (coarse / fine) | 5.03 / 5.61 mm² |
| Hex wrench size | 5.5 mm (ISO 4032) |
| Tap drill (coarse / fine) | 2.5 mm / 2.65 mm |
| Clearance hole (ISO 273 medium) | 3.4 mm |
Pitches per ISO 261/262; stress area per ISO 898-1; tap drill = nominal diameter minus pitch. M3 coarse vs fine →