Status : Book Study

A standard imperial unit of measurement equal to 0.125 inches (3.175 mm), widely used in woodworking as a baseline reference for blade kerfs, material thickness, and layout margins.

While North America relies on imperial terms like 1/8″, Europe, ANZ, Scandinavia, China has fully transitioned to metric (3mm) leaving the UK, Canada, India, Japan (to an extent) in a hybrid position where both systems comfortably coexist.

Note for Metric Woodworkers: In metric workshops across Europe and the UK, this measurement is typically rounded to 3mm.

My Workbench Note: First Impression

The 1/8″ mark is where imperial measurements finally start feeling manageable to a metric mind. Sitting at roughly 3.2 mm, it’s a big, friendly milestone on the scale—and happens to be the exact thickness of a standard table saw blade kerf, a classic hardboard panel, or a heavy chisel blade.

Quick beginner takeaways

• Metric Anchor: 1/8″ equals precisely 3.175 mm (think of it as just under 3.2 mm, or roughly 3 mm for quick mental estimates.

• Bench Tip: Keep 1/8″ in mind whenever you lay out cuts—because it matches standard saw blade kerfs, every cut you make deletes roughly 1/8″ or 3.2 mm of timber into sawdust.

---