Metric Thread Data

Thread Conversion Table

Due to the differences in thread angles and pitches, the thread sizes shown below are not directly interchangeable with each other. This table is only to help find a nearest equivalent sized fastener.

Metric Coarse Metric Fine BSF/BSW UNC UNF
M2 x 0.4 - - 1-64 1-72
M2.5 x 0.45 - - 3-48 3-56
M3 x 0.5 - - 4-40 4-48
M3.5 x 0.6 - - 6-32 6-40
M4 x 0.7 - - 8-32 8-36
M5 x 0.8 - - 10-24 10-32
M6 x 1 M6 x 0.75 1/4" 1/4-20 1/4-28
M8 x 1.25 M8 x 1 5/16" 5/16-18 5/16-24
M10 x 1.5 M10 x 1.25 3/8" 3/8-16 3/8-24
M12 x 1.75 M12 x 1.25 1/2" 1/2-13 1/2-20
M14 x 2 M14 x 1.5 9/16" 9/16-12 9/16-18
M16 x 2 M16 x 1.5 5/8" 5/8-11 5/8-18
M20 x 2.5 M20 x 1.5 3/4" 3/4-10 3/4-16
M24 x 3 M24 x 2 1" 1-8 1-12
M30 x 3.5 M30 x 2 1-1/8" 1 1/4-7 1 1/8-12
M36 x 4 M36 x 3 1-3/8" 1 1/2-6 1 1/4-12
ISO 724 - Metric Threads

ISO 724 - Metric Threads

Dimensions of metric threads according ISO 724

The pitch varies from coarse to extra fine with up to 5 different pitches for some dimensions. The thread angle is 60o and the thread depth is 0.614 x pitch.

Metric Threads - Coarser Threads

The table below indicates some of the most used coarse threads up to size M 68. Note that the ISO 724 standard specifies threads up to M 300. The table below is not complete. 

Size - Nominal Diameter
(mm)		Pitch1)
(mm)
Clearance Drill
(mm)
Tap Drill
(mm)
Tensile Stress Area
(mm2)
M 1.6 0.35 1.8 1.25
M 2 0.40 2.4 1.60
M 2.5 0.45 2.90 2.00
M 3 0.50 3.40 2.50
M 3.5 0.60 3.90 2.90
M 4 0.70 4.50 3.30 8.78
M 5 0.80 5.50 4.20 14.2
M 6 1.00 6.60 5.00 20.1
M 8 1.25 9.00 6.80 36.6
M 10 1.50 12.00 8.50 58.0
M 12 1.75 14.00 10.20 84.3
M 14 2.00 16.00 12.00
M 16 2.00 18.00 14.00 157
M 20 2.50 22.00 17.50 245
M 22 2.50 25.00 19.50
M 24 3.00 27.00 21.00 353
M 27 3.00 30.00 24.00
M 30 3.50 33.00 26.50 561
M 36 4.00 40.00 32.00 817
M 42 4.50 46.00 37.50 1120
M 48 5.00 53.00 43.00 1470
M 56 5.50 62.00 50.50 2030
M 64 6.00 70.00 58.00 2680
M 68 6.00 74.00 62.00

1)

Metric Threads - Finer Threads

It is common to designate metric fine threads with the capital M plus an indication to their nominal outer diameter and their pitch:

M size x pitch

Example:

M 10 x 1.5

The table below indicates the typically used finer threads up to size M 100. Note that the ISO 724 standard specifies threads up to M 300.

Size - Nominal Diameter
(mm)

Pitch1)
(mm)
Tap Drill
(mm)
Tensile Stress Area
(mm2)
M 1.0 x 0.2 0.20 0.80
M 1.1 x 0.2 0.20 0.90
M 1.2 x 0.2 0.20 1.00
M 1.4 x 0.2 0.20 1.20
M 1.6 x 0.2 0.20 1.40
M 1.8 x 0.2 0.20 1.60
M 2 x 0.25 0.25 1.75
M 2.2 x 0.25 0.25 1.95
M 2.5 x 0.35 0.35 2.10
M 3 x 0.35 0.35 2.60
M 3.5 x 0.35 0.35 3.10
M 4 x 0.5 0.50 3.50
M 4.5 x 0.5 0.50 4.00
M 5 x 0.5 0.50 4.50
M 5.5 x 0.5 0.50 5.00
M 6 x 0.75 0.75 5.20 20.1
M 7 x 0.75 0.75 6.20
M 8 x 0.75 0.75 7.20
M 8 x 1.0 1.00 7.00 39.2
M 9 x 0.75 0.75 8.20
M 9 x 1 1.00 8.00
M 10 x 0.75 0.75 9.20
M 10 x 1 1.00 9.00 64.5
M 10 x 1.25 1.25 8.80 61.2
M 11 x 0.75 0.75 10.20
M 11 x 1 1.00 10.00
M 12 x 1 1.00 11.00
M 12 x 1.25 1.25 10.80 92.1
M 12 x 1.5 1.50 10.50 88.1
M 14 x 1.0 1.00 13.00
M 14 x 1.25 1.25 12.80
M 14 x 1.5 1.50 12.50
M 15 x 1 1.00 14.00
M 15 x 1.5 1.50 13.50
M 16 x 1 1.00 15.00 178
M 16 x 1.5 1.50 14.50 167
M 17 x 1.0 1.00 16.00
M 17 x 1.5 1.50 15.50
M 18 x 1.0 1.00 17.00
M 18 x 1.5 1.50 16.50
M 18 x 2.0 2.00 16.00
M 20 x 1.0 1.00 19.00
M 20 x 1.5 1.50 18.50 272
M 20 x 2.0 2.00 18.00 258
M 22 x 1.0 1.00 21.00
M 22 x 1.5 1.50 20.50
M 22 x 2.0 2.00 20.00
M 24 x 1.0 1.00 23.00
M 24 x 1.5 1.50 22.50 401
M 24 x 2.0 2.00 22.00 384
M 25 x 1.0 1.00 24.00
M 25 x 1.5 1.50 23.50
M 25 x 2.0 2.00 23.00
M 27 x 1.0 1.00 26.00
M 27 x 1.5 1.50 25.50
M 27 x 2.0 2.00 25.00
M 28 x 1.0 1.00 27.00
M 28 x 1.5 1.50 26.50
M 28 x 2.0 2.00 26.00
M 30 x 1.0 1.00 29.00
M 30 x 1.5 1.50 28.50
M 30 x 2.0 2.00 28.00 621
M 30 x 3.0 3.00 27.00 581
M 32 x 1.5 1.50 30.50
M 32 x 2.0 2.00 30.00
M 33 x 1.5 1.50 31.50
M 33 x 2.0 2.00 31.00
M 33 x 3.0 3.00 30.00
M 35 x 1.5 1.50 33.50
M 35 x 2.0 2.00 33.00
M 36 x 1.5 1.50 34.50
M 36 x 2.0 2.00 34.00 915
M 36 x 3.0 3.00 33.00 865
M 39 x 1.5 1.50 37.50
M 39 x 2.0 2.00 37.00
M 39 x 3.0 3.00 36.00
M 40 x 1.5 1.50 38.50
M 40 x 2.0 2.00 38.00
M 40 x 3.0 3.00 37.00
M 42 x 1.5 1.50 40.50
M 42 x 2.0 2.00 40.00
M 42 x 3.0 3.00 39.00 1210
M 42 x 4.0 4.00 38.00 1150
M 45 x 1.5 1.50 43.50
M 45 x 2.0 2.00 43.00
M 45 x 3.0 3.00 42.00
M 45 x 4.0 4.00 41.00
M 48 x 1.5 1.50 46.50
M 48 x 2.0 2.00 46.00
M 48 x 3.0 3.00 45.00 1600
M 48 x 4.0 4.00 44.00 1540
M 50 x 1.5 1.50 48.50
M 50 x 2.0 2.00 48.00
M 50 x 3.0 3.00 47.00
M 52 x 1.5 1.50 50.50
M 52 x 2.0 2.00 50.00
M 52 x 3.0 3.00 49.00
M 52 x 4.0 4.00 48.00
M 55 x 1.5 1.50 53.50
M 55 x 2.0 2.00 53.00
M 55 x 3.0 3.00 52.00
M 55 x 4.0 4.00 51.00
M 56 x 1.5 1.50 54.50
M 56 x 2.0 2.00 54.00
M 56 x 3.0 3.00 53.00
M 56 x 4.0 4.00 52.00
M 58 x 1.5 1.50 56.50
M 58 x 2.0 2.00 56.00
M 58 x 3.0 3.00 55.00
M 58 x 4.0 4.00 54.00
M 60 x 1.5 1.50 58.50
M 60 x 2.0 2.00 58.00
M 60 x 3.0 3.00 57.00
M 60 x 4.0 4.00 56.00
M 62 x 1.5 1.50 60.50
M 62 x 2.0 2.00 60.00
M 62 x 3.0 3.00 59.00
M 62 x 4.0 4.00 58.00
M 64 x 1.5 1.50 62.50
M 64 x 2.0 2.00 62.00
M 64 x 3.0 3.00 61.00
M 64 x 4.0 4.00 60.00
M 65 x 1.5 1.50 63.50
M 65 x 2.0 2.00 63.00
M 65 x 3.0 3.00 62.00
M 65 x 4.0 4.00 61.00
M 68 x 1.5 1.50 66.50
M 68 x 2.0 2.00 66.00
M 68 x 3.0 3.00 65.00
M 68 x 4.0 4.00 64.00
M 70 x 1.5 1.50 68.50
M 70 x 2.0 2.00 68.00
M 70 x 3.0 3.00 67.00
M 70 x 4.0 4.00 66.00
M 70 x 6.0 6.00 64.00
M 72 x 1.5 1.50 70.50
M 72 x 2.0 2.00 70.00
M 72 x 3.0 3.00 69.00
M 72 x 4.0 4.00 68.00
M 72 x 6.0 6.00 66.00
M 75 x 1.5 1.50 73.50
M 75 x 2.0 2.00 73.00
M 75 x 3.0 3.00 72.00
M 75 x 4.0 4.00 71.00
M 75 x 6.0 6.00 69.00
M 76 x 1.5 1.50 74.50
M 76 x 2.0 2.00 74.00
M 76 x 3.0 3.00 73.00
M 76 x 4.0 4.00 72.00
M 76 x 6.0 6.00 70.00
M 80 x 1.5 1.50 78.50
M 80 x 2.0 2.00 78.00
M 80 x 3.0 3.00 77.00
M 80 x 4.0 4.00 76.00
M 80 x 6.0 6.00 74.00
M 85 x 2.0 2.00 83.00
M 85 x 3.0 3.00 82.00
M 85 x 4.0 4.00 81.00
M 85 x 6.0 6.00 79.00
M 90 x 2.0 2.00 88.00
M 90 x 3.0 3.00 87.00
M 90 x 4.0 4.00 86.00
M 90 x 6.0 6.00 84.00
M 95 x 2.0 2.00 93.00
M 95 x 3.0 3.00 92.00
M 95 x 4.0 4.00 91.00
M 95 x 6.0 6.00 89.00
M 100 x 2.0 2.00 98.00
M 100 x 3.0 3.00 97.00
M 100 x 4.0 4.00 96.00
M 100 x 6.0 6.00 94.00

Related ISO Standards

  • ISO 68:1973 ISO general purpose screw threads - Basic profile
  • ISO 261:1973 ISO general purpose metric screw threads - General plan
  • ISO 262:1973 ISO general purpose metric screw threads - Selected sizes for screws, bolts and nuts
  • ISO 724:1993 ISO general-purpose metric screw threads - Basic dimensions
  • ISO 965-1:1980 ISO general purpose metric screw threads - Tolerances - Part 1: Principles and basic data
  • ISO 965-2:1980 ISO general purpose metric screw threads - Tolerances - Part 2: Limits of sizes for general purpose bolt and nut threads - Medium quality
  • ISO 965-3:1980 ISO general purpose metric screw threads - Tolerances - Part 3: Deviations for constructional threads
  • ISO 1502:1996 ISO general-purpose metric screw threads - Gauges and gauging

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