Sizes for grommets and eyelets are generally listed as the measurement of the inner diameter (the hole size). In the chart below we have provided exact measurements for inner diameter/outer diameter/height.
| Size | Inner Diameter (mm) | Outer Diameter (mm) | Height (mm) |
| #00000 (1/16’’) | 1.5 | 3.5 | 4 |
| #0000 (1/8’’) | 3.2 | 8.5 | 7 |
| #000 (5/32’’) | 4 | 7.5 | 5 |
| #00 (3/16’’) | 4.5 | 9 | 5 |
| #0 (1/4’’) | 6 | 11.5 | 5.5 |
| #1 (5/16’’) | 7 | 17.5 | 6 |
| #2 (3/8’’) | 9 | 19 | 7 |
| #3 (7/16’’) | 12 | 22 | 7 |
| #4 (1/2’’) | 15 | 28 | 9 |
| #5 (5/8’’) | 17 | 32 | 9 |
| #6 (3/4’’) | 18 | 34 | 10 |
| #8 (1-1/8’’) | 30 | 50 | 8 |
| #10 (1-7/16’’) | 35 | 48 | 7 |
| #12 (1-9/16’’) | 41.5 | 61.5 | 11 |