The Janka Hardness Scale, Visualized
The Janka hardness scale measures a wood’s resistance to denting and wear by recording the pounds-force needed to press a 0.444-inch steel ball halfway into a sample. The higher the number, the harder the wood. Ratings are expressed in lbf (United States), kgf (Europe), or N (Australia) — all measuring the same property in different units.
119 wood species, ranked hardest to softest. Filter by name, compare any two side by side, and find where your species actually lands. Picking flooring or choosing stock for a workbench top — the number you need is right here.
All 119 Species, Ranked by Hardness
Sorted hardest to softest. Australian Buloke tops the list at 5,060 lbf, the hardest species by most published accounts. Balsa sits at the far end with 100 lbf. Black Ironwood (3,660 lbf) is the hardest wood native to the United States. Strand-woven bamboo is listed for comparison, though it's a grass product rather than a true hardwood.
Compare Two Woods
Pick any two species from the dropdowns. The result updates as soon as you make a selection.
What the Number Actually Means
Put simply: it's the force needed to push a 0.444-inch (11.28 mm) steel ball halfway into a wood sample. Higher number, harder wood, better dent resistance and abrasion resistance. That's the core of it.
Two things worth knowing before you rely on it, though. The rating always measures side hardness, meaning the face of a board perpendicular to the grain, because that's the surface you actually walk on. End-grain tests on the same species run higher, which is why published flooring specs always use side hardness. For woodworkers: domestic hardwoods above roughly 2,000 lbf wear down standard steel blades noticeably faster. Plan for carbide.
The test goes back to 1906. Gabriel Janka (1864 to 1932) adapted it from the Brinell method used for metals, setting the ball diameter so the contact area comes out to exactly one square centimeter, which keeps results comparable across labs worldwide. For a deeper look at what affects the numbers and where they can mislead, the full guide to the Janka hardness scale covers that ground.
One quick note on units: the U.S. reports in pounds-force (lbf), Europe and Japan use kilograms-force (kgf), Australia uses newtons (N). If you're comparing a European supplier's spec to something on this page, 1 lbf equals roughly 0.454 kgf or 4.448 N. The unit toggle handles the conversion automatically.
How to Read a Janka Rating
- Red oak is the benchmark (1,290 lbf).
- Red oak became the standard reference point because it's been used in North American flooring for well over a century and its hardness data is thoroughly documented by The Wood Database and the USDA Forest Products Laboratory. When a flooring guide says a wood is "1.5 times harder than red oak," the math starts at 1,290 lbf. A species at 2,580 lbf takes roughly double the force to dent.
- 1,500 lbf is the common flooring threshold.
- Think of 1,500 lbf as the rough line where most flooring professionals start recommending a species for genuinely busy spaces: hallways, kitchens, entryways where kids and dogs run through. Between 1,000 and 1,500 lbf handles typical residential rooms well. Below 1,000 lbf is better suited to bedrooms, offices, or spaces where character marks aren't a problem. These aren't rigid rules; a quality finish and a solid subfloor can matter just as much as the hardness number.
- Test samples are not finished floors.
- Worth being clear about this: the test runs on small, pristine heartwood samples at exactly 12% moisture content, per ASTM D143, as documented by the USDA Forest Products Laboratory Wood Handbook. Not on the plank you're buying. Not on anything with a finish coat, variable grain, or the humidity swings that come with living in a real house. The numbers are reliable for comparing species to each other. They're not a guarantee of how your specific floor holds up.
Common Questions About the Janka Scale
What Janka hardness rating is good for hardwood flooring?
It depends on how the room gets used. Commercial-style traffic — a busy mudroom, an open-plan kitchen-dining area, anywhere furniture moves regularly — points toward 1,500 lbf and above. A home library, guest room, or low-traffic office works well in the 1,000–1,500 range. Below 1,000 lbf suits spaces that don't see much foot traffic, or anywhere you want a softer feel underfoot and don't mind the floor showing its age. Walnut sits at 1,010 lbf, for reference — it's a popular choice for exactly that last category.
Does a higher Janka rating always mean better flooring?
Not always. Harder wood dents less, but it's often more brittle, harder to nail, and less forgiving if your subfloor has any give. Species above 3,000 lbf, like the dense South American and Australian exotics, frequently need pre-drilled pilot holes to avoid splitting on installation. On top of that, a softer species with a quality aluminum oxide finish often outperforms a harder unfinished wood in everyday scratch resistance. Pick for the room, not the ranking.
Can Janka ratings be compared across different countries?
Yes. The test method is standardized under ASTM D143, so a 1,290 lbf red oak in Ohio and a 585 kgf red oak in a German catalogue are the same measurement in different notation. Where comparisons get slippery is natural species variation: values for the same species can differ by around 5% or more between sources, depending on the sample, testing lab, and growing region. The unit toggle on this page switches between lbf, kgf, and N automatically.
Are Janka hardness ratings measured on finished flooring?
No. The number comes from a controlled lab test on unfinished wood samples — the guide card above explains the details. What that means in practice: two floors with the same Janka rating can perform very differently depending on the finish coat, plank thickness, how the subfloor was prepared, and the humidity in your area. The Janka number is a useful species-to-species comparison. For long-term floor performance, installation quality and finish type are at least as important.
Need a Sortable Table or Flooring Advice?
The full hardness chart lets you sort all 119 species by name, rating, or region. If you're narrowing down flooring options, the best flooring woods guide has the top picks broken down by room type and traffic level.
More questions — unit conversions, moisture effects, how Janka compares to engineered and composite products — are in the Janka hardness FAQ. If you want to add this comparison tool to your own site, the embeddable Janka widget is free and drops in with a single line of code.
Sources. The Janka values in this tool draw on The Wood Database (wood-database.com), the USDA Forest Products Laboratory Wood Handbook, and ASTM International standards ASTM D143 and ASTM D1037. See data sources and methodology for a full description of how values were selected and where they differ across sources. Values are approximate averages and vary by sample, moisture content, and testing lab.