Utility Loft → Socket Size → Standard to Metric
Standard to Metric Conversion
Find the closest metric (mm) size for any SAE (inch) socket or wrench, with the exact width and fit. Convert a single size below.
Closest SAE size—
Enter a metric size above to find the closest SAE (inch) wrench.
SAE to metric chart
| SAE | Decimal | Width (mm) | Closest metric | Fit |
|---|---|---|---|---|
| 5/32" | 0.1563 | 3.97 | 4 mm | ≈ exact |
| 3/16" | 0.1875 | 4.76 | 5 mm | close |
| 7/32" | 0.2188 | 5.56 | 5.5 mm | ≈ exact |
| 1/4" | 0.2500 | 6.35 | 6 mm | close |
| 9/32" | 0.2813 | 7.14 | 7 mm | ≈ exact |
| 5/16" | 0.3125 | 7.94 | 8 mm | ≈ exact |
| 11/32" | 0.3438 | 8.73 | 9 mm | close |
| 3/8" | 0.3750 | 9.53 | 10 mm | loose |
| 7/16" | 0.4375 | 11.11 | 11 mm | ≈ exact |
| 1/2" | 0.5000 | 12.70 | 13 mm | close |
| 9/16" | 0.5625 | 14.29 | 14 mm | close |
| 5/8" | 0.6250 | 15.88 | 16 mm | ≈ exact |
| 11/16" | 0.6875 | 17.46 | 17 mm | loose |
| 3/4" | 0.7500 | 19.05 | 19 mm | ≈ exact |
| 13/16" | 0.8125 | 20.64 | 21 mm | close |
| 7/8" | 0.8750 | 22.23 | 22 mm | close |
| 15/16" | 0.9375 | 23.81 | 24 mm | ≈ exact |
| 1" | 1.0000 | 25.40 | 24 mm | loose |
| 1-1/16" | 1.0625 | 26.99 | 27 mm | ≈ exact |
| 1-1/8" | 1.1250 | 28.58 | 30 mm | loose |
| 1-1/4" | 1.2500 | 31.75 | 32 mm | close |
Width is the SAE size in mm (fraction × 25.4). Loose matches can slip — use an SAE socket for tight inch fasteners.
Related
Frequently asked questions
What is 1/2 inch in metric?
1/2 inch is 12.7 mm, closest to a 13 mm socket (0.3 mm larger) — a close fit. A 12 mm would be too small.
What is 3/8 inch in metric?
3/8 inch is 9.53 mm, closest to 10 mm — but 10 mm is about 0.5 mm larger, so it's a loose match.
What is 3/4 inch in metric?
3/4 inch is 19.05 mm, practically identical to a 19 mm socket — the two are interchangeable.