Wood hardness comparator
Janka hardness is the force needed to press a steel ball half its diameter into a board. Higher = harder = more dent-resistant. This isn't the whole story (a stable, medium-hard wood is often a better floor than a hard, unstable one) but it's the single most useful number when comparing species for wear surfaces.
Comparator
Full Janka table
| Species | Janka (lbf) | vs ref |
|---|
The honest version of Janka
Janka tells you about dent resistance. It doesn't tell you about:
- Stability — a hard wood that moves a lot (like beech) will gap and cup more than a softer stable wood (like walnut).
- Wear pattern — softer woods scratch but don't show the scratch as glaringly. Hardwoods hold up to abuse but a single deep gouge is more visible.
- Finishing — some hard woods (white oak, ash) have open grain that telegraphs through finishes; some softer woods (cherry, walnut) finish glassy-smooth.
- Tooling — very hard woods dull edges faster. Working lignum vitae by hand is a workout.
For most hobbyists, hardness matters most on wear surfaces: floors, bench tops, cutting boards. For everything else, choose for colour and stability first.
Limitations
- Janka is measured on kiln-dried lumber. Green wood tests ~30% lower.
- Numbers are species averages. Specific gravity varies by 10–20% within a species, and Janka scales with that.
- The table doesn't capture tropical hardwoods' tendency to contain silica (dulls tools quickly) or extractives that resist glue.
- Cutting boards: a hardness floor matters less than closed grain and food safety. Hard maple and walnut both work; oak (with open grain) is widely considered unsuitable despite being harder than walnut.
Frequently asked questions
Is harder always better?
No. Harder woods are heavier, harder to work, dull tools faster, and often more dimensionally unstable. The right hardness is the one your project actually needs — too soft dents easily, too hard is overkill and costs you in tooling and effort.
What's the Janka of bamboo flooring?
Around 1300–1400 depending on construction. But bamboo is a grass, behaves differently under tools, and has its own quirks (splits along the grain, swells with humidity). Use the Janka number as a relative dent-resistance clue, not as a direct substitute.
Why are imported tropical woods so much harder?
Slow growth in dense tropical forests produces very tightly packed growth rings with high specific gravity. That's also why many of these species are now on CITES Appendix II — they're slow to renew. For most hobbyist projects, a domestic hardwood will perform just as well.