Janka Test and Hardwood Floor Hardness Explained

By the FlooringFirst team

The Janka hardness scale measures the force needed to drive a steel ball into wood; the higher the number, the harder the wood and the more resistant it is to dents. Most oak floors sit between about 1,100 and 1,400 lbf, black walnut is around 1,000 and hard maple is about 1,450.

Below you'll find a Janka chart for popular flooring woods in pounds-force and newtons, how the test works, and what the numbers can't tell you about your own floor.

Janka hardness chart for popular flooring woods

These figures are averages from published tests, so a board from your floor may score a little higher or lower. The US figure is pounds-force (lbf), and multiplying by 4.448 gives newtons.

Larch is a good example of how much the numbers can vary: published lists put it anywhere from about 590 to 1,200 lbf, depending on the species and the source. Oak is the same, with English oak listed at 1,120 lbf and American white oak at 1,360 lbf. Treat the chart as a guide for comparing woods, and check the exact board with your supplier.

How does the Janka test work?

The test presses an 11.28 mm (0.444 inch) steel ball into a wood sample until it's embedded to half its diameter, and records the force needed. It's a side hardness test, so it shows how well a species resists denting and wear on the face of a board.

• Results are quoted in lbf in the US, and in newtons, kilonewtons or kilograms-force elsewhere, which is why the same wood can appear as 1,360 lbf or 6,000 N.
• Samples are usually tested at around 12% moisture content, so the figures reflect a dry, settled board.
• A higher number means a harder wood. It doesn't mean a better floor, because hardness is only one part of how a floor performs.

What does the Janka scale not tell you?

It tells you about dent resistance for a species, and nothing about the finished floor in your home. A few things change how a floor behaves without changing its Janka rating.

• The finish protects against scratches and wear, but it doesn't make the wood itself harder.
• Engineered boards depend on the species of the top layer, its thickness and the core underneath. See our engineered wood floor installation service for how they're fitted.
• Grain direction, board thickness and the subfloor all affect how a board takes a knock.
• Hardwoods still scratch, and softwoods can be sanded and refinished many times. Our wood floor scratch repair and wood floor sanding and restoration services deal with marks as they appear.
• Very hard woods take longer to cut, nail and sand, which can affect how a job is planned.

The practical lesson is that nearly every popular flooring species is hard-wearing enough for everyday use. If you're weighing solid, engineered and parquet options, our guide to solid, engineered and parquet floors compared goes through the trade-offs.

Are hardwoods always harder than softwoods?

No. Hardwood and softwood are botanical terms, not measures of hardness. Hardwoods come from broadleaf flowering trees, whose seeds are enclosed, and softwoods come from conifers, whose seeds are not.

• Balsa is a hardwood and one of the softest woods there is.
• European yew is a softwood, yet at about 1,520 lbf it's harder than English oak at 1,120 lbf.
• Siberian larch, another softwood, scores about 1,100 lbf, close to English oak.
• The very top of the scale is mostly tropical hardwoods such as ipe.

The old rule that hardwoods are tougher is a useful starting point at best. Check the Janka rating of the actual species, and don't rule out a softwood on its name alone.

What is the hardest wood in the UK?

Hornbeam is the usual answer for the hardest timber among British trees, at about 1,630 lbf, well above English oak. The Woodland Trust describes it as having the hardest wood of any tree in Europe, and it's occasionally used for flooring. Oak, ash and beech are far more common for floors because they're easier to source in board sizes and still very hard-wearing.

Frequently Asked Questions about wood hardness

What is a good Janka rating for a wood floor?

For most homes, a rating of about 1,000 to 1,400 lbf works well, which covers walnut, oak, ash and beech. Go above 1,400 lbf for busy hallways and kitchens or commercial use.

Is oak harder than walnut?

Yes. Oak is listed at about 1,120 to 1,360 lbf depending on the species, and black walnut at about 1,010 lbf.

How hard is larch?

Siberian larch is about 1,100 lbf, similar to English oak, although some lists show larch lower or higher. Larch is a softwood, so the species and source matter.

How hard is yew?

European yew is about 1,520 lbf, harder than English oak, even though it's classed as a softwood. It's rarely used for flooring.

How is wood hardness measured?

With the Janka test, which records the force needed to press an 11.28 mm steel ball into the wood to half its diameter.

Is there a Mohs scale for wood?

No. The Mohs scale ranks how minerals scratch each other, and wood is rated on the Janka scale instead.

Does a harder wood scratch less?

Not necessarily. Janka shows resistance to denting, while scratches depend mostly on the finish and how the floor is used. Felt pads and regular care help on any species.

Does the Janka scale apply to engineered wood?

It applies to the species of the top layer. The thickness of that layer and the core beneath it also affect how the floor handles knocks.

Need help choosing the right wood?

If you're deciding between woods, or wondering whether a softer species will cope with kids and pets, book a free site survey and we'll talk it through at your property. You can also call us on 020 8830 9782. If you already know you want a real wood floor, see our solid wood floor fitting service.