**Metric to Standard** |** Standard to Metric**

A user-friendly socket size conversion guide makes switching between metric and standard sockets a breeze.

Use this chart to simplify your socket conversions and streamline your tool selection.

Common **socket conversions** and **downloadable chart(pdf)** are below the chart.

MM to inch and inch to mm socket conversion charts vary slightly because the converted socket should be larger than the fastener. If it's not slightly larger it won't fit.

## Socket Conversion Chart

From Metric | To Standard Socket |
---|---|

4 mm | 5/32" |

5 mm | 7/32″ |

6 mm | 1/4″ |

7 mm | 9/32″ |

8 mm | 11/32″ |

9 mm | 3/8″ |

10 mm | 13/32″ |

11 mm | 7/16″ |

12 mm | 1/2″ |

13 mm | 17/32″ |

14 mm | 9/16″ |

15 mm | 19/32″ |

16 mm | 21/32" |

17 mm | 11/16″ |

18 mm | 23/32″ |

19 mm | 3/4″ |

20 mm | 13/16″ |

21 mm | 27/32″ |

22 mm | 7/8″ |

23 mm | 29/32″ |

24 mm | 31/32″ |

25 mm | 1″ |

26 mm | 1 1/32″ |

27 mm | 1 1/16″ |

28 mm | 1 1/8″ |

29 mm | 1 5/32″ |

30 mm | 1 3/16″ |

31 mm | 1 7/32″ |

32 mm | 1 9/32″ |

33 mm | 1 5/16″ |

34 mm | 1 11/32″ |

35 mm | 1 3/8″ |

36 mm | 1 7/16″ |

37 mm | 1 15/32″ |

38 mm | 1 1/2″ |

39 mm | 1 9/16″ |

40 mm | 1 19/32″ |

41 mm | 1 5/8″ |

42 mm | 1 21/32″ |

43 mm | 1 23/32″ |

44 mm | 1 3/4″ |

45 mm | 1 25/32″ |

46 mm | 1 13/16″ |

47 mm | 1 7/8″ |

48 mm | 1 29/32″ |

49 mm | 1 15/16″ |

50 mm | 1 31/32" |

## Common Socket Conversions

For common mm to inch socket conversions the conversion formula is 25.4 millimeters(mm) per inch. (For spark plug info visit the spark plug socket size page.)

### 4mm Socket to Inches

4 ÷ 25.4 = 0.15748 inches. The closest equivalent Standard size socket is **5/32"**, which is 3.96875 millimeters.

### 5mm Socket to Inches

5 ÷ 25.4 = 0.19685 inches. The closest equivalent Standard size socket is **7/32"**, which is 5.55625 millimeters.

### 6mm Socket to Inches

6 ÷ 25.4 = 0.23622 inches. The closest equivalent Standard size socket is **1/4"**, which is 6.35 millimeters.

### 7mm Socket to Inches

7 ÷ 25.4 = 0.275591 inches. The closest equivalent Standard size socket is **9/32"**, which is 7.14375 millimeters.

### 8mm Socket to Inches

8 ÷ 25.4 = 0.314961 inches. The closest equivalent Standard size socket is **11/32"**, which is 8.73125 millimeters.

### 9mm Socket to Inches

9 ÷ 25.4 = 0.354331 inches. The closest equivalent Standard size socket is **3/8"**, which is 9.525 millimeters.

### 10mm Socket to Inches

10 ÷ 25.4 = 0.393701 inches. The closest equivalent Standard size socket is **13/32"**, which is 10.3187 millimeters.

### 11mm Socket to Inches

11 ÷ 25.4 = 0.433071 inches. The closest equivalent Standard size socket is **7/16"**, which is 11.1125 millimeters.

### 12mm Socket to Inches

12 ÷ 25.4 = 0.472441 inches. The closest equivalent Standard size socket is **1/2"**, which is 12.7 millimeters.

### 13mm Socket to Inches

13 ÷ 25.4 = 0.511811 inches. The closest equivalent Standard size socket is **17/32"**, which is 13.4937 millimeters.

### 14mm Socket to Inches

14 ÷ 25.4 = 0.551181 inches. The closest equivalent Standard size socket is **9/16"**, which is 14.2875 millimeters.

### 15mm Socket to Inches

15 ÷ 25.4 = 0.590551 inches. The closest equivalent Standard size socket is **19/32"**, which is 15.0812 millimeters.

### 16mm Socket to Inches

16 ÷ 25.4 = 0.629921 inches. The closest equivalent Standard size socket is **21/32"**, which is 16.6687 millimeters.

### 17mm Socket to Inches

17 ÷ 25.4 = 0.669291 inches. The closest equivalent Standard size socket is **11/16"**, which is 17.4625 millimeters.

### 18mm Socket to Inches

18 ÷ 25.4 = 0.708661 inches. The closest equivalent Standard size socket is **23/32"**, which is 18.2562 millimeters.

### 19mm Socket to Inches

19 ÷ 25.4 = 0.748031 inches. The closest equivalent Standard size socket is **3/4"**, which is 19.05 millimeters.

### 20mm Socket to Inches

20 ÷ 25.4 = 0.787402 inches. The closest equivalent Standard size socket is **13/16"**, which is 20.6375 millimeters.

### 21mm Socket to Inches

21 ÷ 25.4 = 0.826772 inches. The closest equivalent Standard size socket is **27/32"**, which is 21.4312 millimeters.

### 22mm Socket to Inches

22 ÷ 25.4 = 0.866142 inches. The closest equivalent Standard size socket is **7/8"**, which is 22.225 millimeters.

### 23mm Socket to Inches

23 ÷ 25.4 = 0.905512 inches. The closest equivalent Standard size socket is **29/32"**, which is 23.0187 millimeters.

### 24mm Socket to Inches

24 ÷ 25.4 = 0.944882 inches. The closest equivalent Standard size socket is** 31/32"**, which is 24.6062 millimeters.

### 25mm Socket to Inches

25 ÷ 25.4 = 0.984252 inches. The closest equivalent Standard size socket is **1"**, which is 25.4 millimeters.

### 26mm Socket to Inches

26 ÷ 25.4 = 1.02362 inches. The closest equivalent Standard size socket is **1 1/32"**, which is 26.1937 millimeters.

### 27mm Socket to Inches

27 ÷ 25.4 = 1.06299 inches. The closest equivalent Standard size socket is **1 1/16"**, which is 26.9875 millimeters.

### 28mm Socket to Inches

28 ÷ 25.4 = 1.10236 inches. The closest equivalent Standard size socket is **1 1/8"**, which is 28.575 millimeters.

### 29mm Socket to Inches

29 ÷ 25.4 = 1.14173 inches. The closest equivalent Standard size socket is **1 5/32"**, which is 29.3687 millimeters.

### 30mm Socket to Inches

30 ÷ 25.4 = 1.1811 inches. The closest equivalent Standard size socket is **1 3/16"**, which is 30.1625 millimeters.

### 31mm Socket to Inches

31 ÷ 25.4 = 1.22047 inches. The closest equivalent Standard size socket is **1 7/32"**, which is 30.9562 millimeters.

### 32mm Socket to Inches

32 ÷ 25.4 = 1.25984 inches. The closest equivalent Standard size socket is **1 9/32"**, which is 32.5437 millimeters.

### 33mm Socket to Inches

33 ÷ 25.4 = 1.29921 inches. The closest equivalent Standard size socket is **1 5/16"**, which is 33.3375 millimeters.

### 34mm Socket to Inches

34 ÷ 25.4 = 1.33858 inches. The closest equivalent Standard size socket is **1 11/32"**, which is 34.1313 millimeters.

### 35mm Socket to Inches

35 ÷ 25.4 = 1.37795 inches. The closest equivalent Standard size socket is **1 3/8"**, which is 34.925 millimeters.

### 36mm Socket to Inches

36 ÷ 25.4 = 1.41732 inches. The closest equivalent Standard size socket is **1 7/16"**, which is 36.5125 millimeters.

### 37mm Socket to Inches

37 ÷ 25.4 = 1.45669 inches. The closest equivalent Standard size socket is **1 15/32"**, which is 37.3062 millimeters.

### 38mm Socket to Inches

38 ÷ 25.4 = 1.49606 inches. The closest equivalent Standard size socket is **1 1/2"**, which is 38.1 millimeters.

### 39mm Socket to Inches

39 ÷ 25.4 = 1.53543 inches. The closest equivalent Standard size socket is **1 9/16"**, which is 39.6875 millimeters.

### 40mm Socket to Inches

40 ÷ 25.4 = 1.5748 inches. The closest equivalent Standard size socket is **1 19/32"**, which is 40.4812 millimeters.

### 41mm Socket to Inches

41 ÷ 25.4 = 1.61417 inches. The closest equivalent Standard size socket is **1 5/8"**, which is 41.275 millimeters.

### 42mm Socket to Inches

42 ÷ 25.4 = 1.65354 inches. The closest equivalent Standard size socket is **1 21/32"**, which is 42.0687 millimeters.

### 43mm Socket to Inches

43 ÷ 25.4 = 1.69291 inches. The closest equivalent Standard size socket is **1 23/32"**, which is 43.6563 millimeters.

### 44mm Socket to Inches

44 ÷ 25.4 = 1.73228 inches. The closest equivalent Standard size socket is **1 3/4"**, which is 44.45 millimeters.

### 45mm Socket to Inches

45 ÷ 25.4 = 1.77165 inches. The closest equivalent Standard size socket is **1 25/32"**, which is 45.2437 millimeters.

### 46mm Socket to Inches

46 ÷ 25.4 = 1.81102 inches. The closest equivalent Standard size socket is **1 13/16"**, which is 46.0375 millimeters.

### 47mm Socket to Inches

47 ÷ 25.4 = 1.85039 inches. The closest equivalent Standard size socket is **1 7/8"**, which is 47.625 millimeters.

### 48mm Socket to Inches

48 ÷ 25.4 = 1.88976 inches. The closest equivalent Standard size socket is **1 29/32"**, which is 48.4187 millimeters.

### 49mm Socket to Inches

49 ÷ 25.4 = 1.92913 inches. The closest equivalent Standard size socket is **1 15/16"**, which is 49.2125 millimeters.

### 50mm Socket to Inches

50 ÷ 25.4 = 1.9685 inches. The closest equivalent Standard size socket is **1 31/32"**, which is 50.0062 millimeters.

**Remember**: These are approximate equivalents rounded to the nearest standard socket size that will fit nuts and bolts.

**Also**: Use the Inch-lbs to Foot-lbs guide for help with torque wrench sockets and settings.

## Inch in Millimeters Chart

**New** - Use our inch in millimeters chart for exact conversion measurements.

**Test the Socket** Conversion

After you've completed the conversion process, give the converted socket a try! Attach it to your wrench, gently tighten a bolt, and see how it feels.

If you think it feels too loose, trust your instincts. Applying pressure on a loose socket can cause damage and injury.

**Quick Tip**: If it feels a bit loose, try covering the bolt with a shop cloth before attaching the socket. Keep in mind, this works best with lighter torque.

Ensure that the socket securely grips the fastener without slipping, and verify that it doesn't round off the edges.