Dowel size chart
The dowel pin sizes you can buy, and which size suits your stock. The diameters come from what three makers sell; the sizing rule is a shop tradition and is labelled as one.
Dowel pin sizes sold
| Diameter | Lengths sold (in) | Sources |
|---|---|---|
| 1/4 in (6.4 mm) | Rockler: 1 1/2Milescraft: 1Kreg Tool: 1 1/8 | 3 sources agree |
| 5/16 in (7.9 mm) | Rockler: 1 1/2, 2Milescraft: 1 1/2 | Two sources: Rockler and Milescraft |
| 3/8 in (9.5 mm) | Rockler: 1 1/2, 2, 2 1/2Milescraft: 1 1/2Kreg Tool: 1 1/2 | 3 sources agree |
| 1/2 in (12.7 mm) | Rockler: 2, 2 1/2Kreg Tool: 1 3/4 | Two sources: Rockler and Kreg Tool |
Each maker is the authority for the lengths of its own pins, so lengths are listed by maker rather than averaged. Metric dowel sizes are not covered yet.
Dowel size by stock thickness
A dowel is traditionally about one third the thickness of the stock it joins. Rounded to the nearest size above, that gives:
| Stock | One third | Nearest dowel |
|---|---|---|
| 1/2 in | 0.167 in | 1/4 in |
| 3/4 in | 0.25 in | 1/4 in |
| 1 in | 0.333 in | 5/16 in |
| 1 1/4 in | 0.417 in | 3/8 in |
| 1 1/2 in | 0.5 in | 1/2 in |
Traditional rule, stated by Fine Woodworking (Taunton Press) and Dictum
A third of 1/2 in stock is thinner than any size above, so the smallest is shown. Where a third falls exactly halfway between two sizes, the thinner is shown. The references differ on dowel length, so no length rule is given. How the joint works: dowel joints.
Sources
- Rockler, Spiral Dowel Pins, choose size (1/4 to 1/2 in), read 2026-11-07
- Milescraft, DowelBucket, 375 pcs. (1/4, 5/16 and 3/8 in fluted pins), read 2026-11-07
- Kreg Tool, Kreg Fluted Woodworking Dowels (1/4, 3/8 and 1/2 in), read 2026-11-07
- Fine Woodworking (Taunton Press), Mario Rodriguez, "All About Dowels and Biscuits" (2005), read 2026-11-07
- Dictum, 4 × 3 tips for dowelling with wooden dowels, read 2026-11-07
How sources are counted and labelled: how we source these numbers.