註：基本尺寸小於1mm時，無IT14至IT18。
基本尺寸 | 公差值 | |||||||||||||||
| IT4 | IT5 | IT6 | IT7 | IT8 | IT9 | IT10 | IT11 | IT12 | IT13 | IT14 | IT15 | IT16 | IT17 | IT18 | ||
| 大於 | 到 | µm | mm | |||||||||||||
| - | 3 | 3 | 4 | 6 | 10 | 14 | 25 | 40 | 60 | 0.10 | 0.14 | 0.25 | 0.40 | 0.60 | 1.0 | 1.4 |
| 3 | 6 | 4 | 5 | 8 | 12 | 18 | 30 | 48 | 75 | 0.12 | 0.18 | 0.30 | 0.48 | 0.75 | 1.2 | 1.8 |
| 6 | 10 | 4 | 6 | 9 | 15 | 22 | 36 | 58 | 90 | 0.15 | 0.22 | 0.36 | 0.58 | 0.90 | 1.5 | 2.2 |
| 10 | 18 | 5 | 8 | 11 | 18 | 27 | 43 | 70 | 110 | 0.18 | 0.27 | 0.43 | 0.70 | 1.10 | 1.8 | 2.7 |
| 18 | 30 | 6 | 9 | 13 | 21 | 33 | 52 | 84 | 130 | 0.21 | 0.33 | 0.52 | 0.84 | 1.30 | 2.1 | 3.3 |
| 30 | 50 | 7 | 11 | 16 | 25 | 39 | 62 | 100 | 160 | 0.25 | 0.39 | 0.62 | 1.00 | 1.60 | 2.5 | 3.9 |
| 50 | 80 | 8 | 13 | 19 | 30 | 46 | 74 | 120 | 190 | 0.30 | 0.46 | 0.74 | 1.20 | 1.90 | 3.0 | 4.6 |
| 80 | 120 | 10 | 15 | 22 | 35 | 54 | 87 | 140 | 220 | 0.35 | 0.54 | 0.87 | 1.40 | 2.20 | 3.5 | 5.4 |
| 120 | 180 | 12 | 18 | 25 | 40 | 63 | 100 | 160 | 250 | 0.40 | 0.63 | 1.00 | 1.60 | 2.50 | 4.0 | 6.3 |
| 180 | 250 | 14 | 20 | 29 | 46 | 72 | 115 | 185 | 290 | 0.46 | 0.72 | 1.15 | 1.85 | 2.90 | 4.6 | 7.2 |
| 250 | 315 | 16 | 23 | 32 | 52 | 81 | 130 | 210 | 320 | 0.52 | 0.81 | 1.30 | 2.10 | 3.20 | 5.2 | 8.1 |
| 315 | 400 | 18 | 25 | 36 | 57 | 89 | 140 | 230 | 360 | 0.57 | 0.89 | 1.40 | 2.30 | 3.60 | 5.7 | 8.9 |
| 400 | 500 | 20 | 27 | 40 | 63 | 97 | 155 | 250 | 400 | 0.63 | 0.97 | 1.55 | 2.50 | 4.00 | 6.3 | 9.7 |
