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Socket Size Chart
Every SAE and metric socket and wrench size in order of width, with the closest match in the other system. Or convert a single size below.
Enter a metric size above to find the closest SAE (inch) wrench.
SAE & metric sizes, smallest to largest
| Size | System | Width (mm) | Closest other | Fit |
|---|---|---|---|---|
| 5/32" | SAE | 3.97 | 4 mm | ≈ exact |
| 4 mm | Metric | 4.00 | 5/32" | ≈ exact |
| 4.5 mm | Metric | 4.50 | 3/16" | close |
| 3/16" | SAE | 4.76 | 5 mm | close |
| 5 mm | Metric | 5.00 | 3/16" | close |
| 5.5 mm | Metric | 5.50 | 7/32" | ≈ exact |
| 7/32" | SAE | 5.56 | 5.5 mm | ≈ exact |
| 6 mm | Metric | 6.00 | 1/4" | close |
| 1/4" | SAE | 6.35 | 6 mm | close |
| 7 mm | Metric | 7.00 | 9/32" | ≈ exact |
| 9/32" | SAE | 7.14 | 7 mm | ≈ exact |
| 5/16" | SAE | 7.94 | 8 mm | ≈ exact |
| 8 mm | Metric | 8.00 | 5/16" | ≈ exact |
| 11/32" | SAE | 8.73 | 9 mm | close |
| 9 mm | Metric | 9.00 | 11/32" | close |
| 3/8" | SAE | 9.53 | 10 mm | loose |
| 10 mm | Metric | 10.00 | 3/8" | loose |
| 11 mm | Metric | 11.00 | 7/16" | ≈ exact |
| 7/16" | SAE | 11.11 | 11 mm | ≈ exact |
| 12 mm | Metric | 12.00 | 1/2" | loose |
| 1/2" | SAE | 12.70 | 13 mm | close |
| 13 mm | Metric | 13.00 | 1/2" | close |
| 14 mm | Metric | 14.00 | 9/16" | close |
| 9/16" | SAE | 14.29 | 14 mm | close |
| 15 mm | Metric | 15.00 | 9/16" | loose |
| 5/8" | SAE | 15.88 | 16 mm | ≈ exact |
| 16 mm | Metric | 16.00 | 5/8" | ≈ exact |
| 17 mm | Metric | 17.00 | 11/16" | loose |
| 11/16" | SAE | 17.46 | 17 mm | loose |
| 18 mm | Metric | 18.00 | 11/16" | loose |
| 19 mm | Metric | 19.00 | 3/4" | ≈ exact |
| 3/4" | SAE | 19.05 | 19 mm | ≈ exact |
| 20 mm | Metric | 20.00 | 13/16" | loose |
| 13/16" | SAE | 20.64 | 21 mm | close |
| 21 mm | Metric | 21.00 | 13/16" | close |
| 22 mm | Metric | 22.00 | 7/8" | close |
| 7/8" | SAE | 22.23 | 22 mm | close |
| 15/16" | SAE | 23.81 | 24 mm | ≈ exact |
| 24 mm | Metric | 24.00 | 15/16" | ≈ exact |
| 1" | SAE | 25.40 | 24 mm | loose |
| 1-1/16" | SAE | 26.99 | 27 mm | ≈ exact |
| 27 mm | Metric | 27.00 | 1-1/16" | ≈ exact |
| 1-1/8" | SAE | 28.58 | 30 mm | loose |
| 30 mm | Metric | 30.00 | 1-1/8" | loose |
| 1-1/4" | SAE | 31.75 | 32 mm | close |
| 32 mm | Metric | 32.00 | 1-1/4" | close |
Widths are across-flats. Use the correct-system socket for tight fasteners.
Related
Frequently asked questions
What order are socket sizes in?
This chart lists every SAE and metric size together, sorted smallest to largest by their actual width across the flats. That lets you see exactly which metric and inch sizes sit next to each other.
What is the most useful socket size?
10 mm and 13 mm in metric, and 3/8" and 1/2" in SAE, are among the most-used on cars and household hardware. A basic set spanning 8–19 mm and 5/16"–3/4" covers most jobs.
How close do socket sizes need to match?
Within about 0.2 mm is a safe, snug fit. Beyond roughly 0.4 mm the socket is loose enough to round the corners of a bolt under load, so switch systems for anything tight.