Metric Bolt Dimensions
The charts below gives the dimensions for Hexagon head, Socket cap, Low head socket cap, Socket countersink, Socket button and Shoulder screw with Metric Threads.
Dimensions shown are in mm, if you wish to convert to Inches, please use our universal converter.
We also have information on Imperial and Unified Bolts.
HEXAGON HEAD DIMENSIONS - METRIC - BS 3692:2001
| Nominal Size | Body Diameter (D) | Head Thickness (H) | Across Flats (A/F) | Across Corners (A/C) | ||||
|---|---|---|---|---|---|---|---|---|
| Max | Min | Max | Min | Max | Min | Max | Min | |
| M1.6 | 1.60 | 1.47 | 1.225 | 0.975 | 3.20 | 3.02 | 3.41 | 3.41 |
| M2 | 2.00 | 1.87 | 1.525 | 1.275 | 4.00 | 3.82 | 4.32 | 4.32 |
| M2.5 | 2.50 | 2.38 | 1.825 | 1.575 | 5.00 | 4.82 | 5.45 | 5.45 |
| M3 | 3.00 | 2.87 | 2.125 | 1.875 | 5.50 | 5.32 | 6.01 | 6.01 |
| M4 | 4.00 | 3.84 | 2.925 | 2.675 | 7.00 | 6.78 | 7.66 | 7.66 |
| M5 | 5.00 | 4.82 | 3.650 | 3.350 | 8.00 | 7.78 | 8.79 | 8.79 |
| M6 | 6.00 | 5.82 | 4.150 | 3.850 | 10.00 | 9.78 | 11.05 | 11.05 |
| M8 | 8.00 | 7.78 | 5.450 | 5.150 | 13.00 | 12.73 | 14.38 | 14.38 |
| M10 | 10.00 | 9.78 | 6.580 | 6.220 | 17.00 | 16.73 | 18.90 | 18.90 |
| M12 | 12.00 | 11.73 | 7.680 | 7.320 | 19.00 | 18.67 | 21.10 | 21.10 |
| M14 | 14.00 | 13.73 | 8.980 | 8.620 | 22.00 | 21.67 | 24.49 | 24.49 |
| M16 | 16.00 | 15.73 | 10.180 | 9.820 | 24.00 | 23.67 | 26.75 | 26.75 |
| M20 | 20.00 | 19.67 | 13.150 | 12.650 | 30.00 | 29.16 | 33.53 | 33.53 |
SOCKET CAP SCREW DIMENSIONS - METRIC - BS EN ISO 4762: 1998
| Nominal Size | Body Dia (D) | Head Dia (Dk) | Head Height (K) | Hex Key Size (S) | Key Engagement (T) |
|---|---|---|---|---|---|
| M3 | 3.0 | 5.5 | 3.0 | 2.5 | 1.3 |
| M4 | 4.0 | 7.0 | 4.0 | 3.0 | 2.0 |
| M5 | 5.0 | 8.5 | 5.0 | 4.0 | 2.5 |
| M6 | 6.0 | 10.0 | 6.0 | 5.0 | 3.0 |
| M8 | 8.0 | 13.0 | 8.0 | 6.0 | 4.0 |
| M10 | 10.0 | 16.0 | 10.0 | 8.0 | 5.0 |
| M12 | 12.0 | 18.0 | 12.0 | 10.0 | 6.0 |
| M16 | 16.0 | 24.0 | 16.0 | 14.0 | 8.0 |
| M20 | 20.0 | 30.0 | 20.0 | 17.0 | 10.0 |
SOCKET CAP SCREW DIMENSIONS - LOW HEAD - DIN 7984
| Nominal Size | Body Dia (D) | Head Dia (Dk) | Head Height (K) | Hex Key Size (S) | Key Engagement (T) |
|---|---|---|---|---|---|
| M3 | 3.0 | 5.5 | 2.0 | 2.0 | 1.5 |
| M4 | 4.0 | 7.0 | 2.8 | 2.5 | 2.3 |
| M5 | 5.0 | 8.5 | 3.5 | 3.0 | 2.7 |
| M6 | 6.0 | 10.0 | 4.0 | 4.0 | 3.0 |
| M8 | 8.0 | 13.0 | 5.0 | 5.0 | 3.8 |
| M10 | 10.0 | 16.0 | 6.0 | 7.0 | 4.5 |
| M12 | 12.0 | 18.0 | 7.0 | 8.0 | 5.0 |
| M16 | 16.0 | 24.0 | 9.0 | 12.0 | 5.5 |
| M20 | 20.0 | 30.0 | 11.0 | 14.0 | 7.5 |
SOCKET COUNTERSINK SCREW DIMENSIONS - METRIC - BS EN ISO 10642:1998
| Nominal Size | Body Dia (D) | Head Dia (Dk) | Head Height (K) | Hex Key Size (S) |
|---|---|---|---|---|
| M3 | 3.0 | 6.0 | 1.7 | 2.0 |
| M4 | 4.0 | 8.0 | 2.3 | 2.5 |
| M5 | 5.0 | 10.0 | 2.8 | 3.0 |
| M6 | 6.0 | 12.0 | 3.3 | 4.0 |
| M8 | 8.0 | 16.0 | 4.4 | 5.0 |
| M10 | 10.0 | 20.0 | 5.5 | 6.0 |
| M12 | 12.0 | 24.0 | 6.5 | 8.0 |
| M16 | 16.0 | 30.0 | 7.5 | 10.0 |
| M20 | 20.0 | 37.0 | 8.5 | 12.0 |
SOCKET BUTTON SCREW DIMENSIONS - METRIC - BS EN ISO 7380-1 : 2011
| Nominal Size | Body Dia (D) | Head Dia (Dk) | Head Height (K) | Hex Key Size (S) |
|---|---|---|---|---|
| M3 | 3.0 | 5.7 | 1.65 | 2.0 |
| M4 | 4.0 | 7.6 | 2.20 | 2.5 |
| M5 | 5.0 | 9.5 | 2.75 | 3.0 |
| M6 | 6.0 | 10.5 | 3.30 | 4.0 |
| M8 | 8.0 | 14.0 | 4.40 | 5.0 |
| M10 | 10.0 | 18.0 | 5.50 | 6.0 |
| M12 | 12.0 | 21.0 | 6.60 | 8.0 |
| M16 | 16.0 | 28.0 | 8.80 | 10.0 |
SOCKET HEAD SHOULDER SCREW DIMENSIONS - METRIC
| Nominal Size | Thread Size | Shoulder Dia (Ds) | Head Dia (Dk) | Head Height (K) | Hex Key Size (S) |
|---|---|---|---|---|---|
| M5 | M4 | 6.0 | 10.0 | 4.5 | 3.0 |
| M6 | M5 | 8.0 | 13.0 | 5.5 | 4.0 |
| M8 | M6 | 10.0 | 16.0 | 7.0 | 5.0 |
| M10 | M8 | 12.0 | 18.0 | 9.0 | 6.0 |
| M12 | M10 | 16.0 | 24.0 | 11.0 | 8.0 |
| M16 | M12 | 20.0 | 30.0 | 14.0 | 10.0 |
| M20 | M16 | 24.0 | 36.0 | 16.0 | 12.0 |
Affiliate Partners
Help support us by using our affiliate links below.
Link To Amazon.com
Link To Amazon.co.uk