Janka Hardness Scale Chart for Common Wood Species

The Janka hardness scale measures how strongly wood resists indentation. It is useful for comparing flooring and furniture woods, but it does not measure scratch resistance, overall strength, or durability. It can also support species identification when combined with grain, color, end grain, density, and other clues.

What is the Janka hardness scale?

The Janka hardness scale ranks wood according to the force required to press a steel ball into its surface. Higher numbers indicate greater resistance to dents and concentrated pressure. Lower numbers indicate softer wood that will usually mark more easily.

In the United States, Janka hardness is commonly reported in pounds-force, abbreviated lbf. Metric charts may report the same result in newtons or kilonewtons. One pound-force is about 4.448 newtons.

For example, eastern white pine is commonly listed around 380 lbf, while red oak is about 1,290 lbf. Red oak therefore resists indentation much more strongly under standardized test conditions. That does not mean every red oak board is equally hard, or that pine is unsuitable for furniture and floors.

The scale is most helpful for comparing:

• Resistance to dents from shoes, chair legs, tools, and dropped objects
• Relative hardness among flooring species
• How easily a wood may machine, nail, carve, or sand
• Whether a tabletop may show pressure marks during ordinary use
• Hardness as one supporting clue during wood identification

A Janka rating is a comparison tool, not a complete grade for wood quality or performance.

Hardness is different from density, stiffness, strength, stability, and decay resistance. These properties sometimes correlate, but they are not interchangeable.

How does the Janka hardness test work?

The standard test uses a hardened steel ball that is 0.444 inch, or 11.28 millimeters, in diameter. The machine records the force needed to embed the ball into the wood to half its diameter. At that depth, the circular impression has a projected area of 100 square millimeters.

A simplified version of the process is:

1. Prepare a clear wood specimen with controlled dimensions and moisture conditions.
2. Place the sample in a testing machine with the selected face exposed.
3. Press the 0.444-inch steel ball into the wood at a controlled rate.
4. Continue until the ball reaches half its diameter.
5. Record the maximum force required to reach that depth.
6. Repeat the test on additional specimens and calculate a representative result.

Published flooring values usually refer to side hardness, meaning the ball is pressed into a face oriented across the grain rather than directly into the end grain. ASTM D143 is a commonly referenced testing standard in North America, although published charts can come from different laboratories, sample groups, and standards.

Moisture content matters. Wet wood is typically softer than properly dried wood. The board’s growth conditions, grain orientation, extractive content, and position within the tree can also affect the result. A chart should therefore be read as a typical reference, not a guarantee for a particular plank.

What are the Janka ratings of common wood species?

The following Janka hardness scale chart lists approximate side-hardness values for common North American and imported woods. Values can vary by source and specimen. Newton figures are rounded conversions from pounds-force.

| Wood species | Approximate Janka hardness | Approximate metric value | Practical context | |---|---:|---:|---| | Balsa | 70 lbf | 310 N | Extremely soft and easily dented | | Eastern white pine | 380 lbf | 1,690 N | Soft, lightweight, and easy to work | | American basswood | 410 lbf | 1,820 N | Favored for carving; marks easily | | Red alder | 590 lbf | 2,620 N | Moderately soft cabinet and furniture wood | | Douglas fir | 660 lbf | 2,940 N | Common structural and softwood flooring material | | Longleaf southern yellow pine | 870 lbf | 3,870 N | Harder than many familiar softwoods | | Honduran mahogany | 900 lbf | 4,000 N | Workable furniture and instrument wood | | American black cherry | 950 lbf | 4,230 N | Medium hardness with good workability | | Black walnut | 1,010 lbf | 4,490 N | Popular furniture wood; softer than oak | | Teak | 1,070 lbf | 4,760 N | Moderately hard with oily extractives | | Yellow birch | 1,260 lbf | 5,600 N | Hard, close-grained furniture wood | | Northern red oak | 1,290 lbf | 5,740 N | Common benchmark for flooring comparisons | | White ash | 1,320 lbf | 5,870 N | Hard and elastic; used for handles and furniture | | White oak | 1,360 lbf | 6,050 N | Slightly harder than red oak on typical charts | | Sapele | 1,410 lbf | 6,270 N | Dense tropical hardwood used in millwork | | Hard maple | 1,450 lbf | 6,450 N | Fine-textured and resistant to indentation | | Shagbark hickory | 1,880 lbf | 8,360 N | Very hard North American hardwood | | Brazilian cherry, or jatoba | 2,350 lbf | 10,450 N | Dense flooring wood that can be difficult to machine | | Gaboon ebony | 3,220 lbf | 14,320 N | Extremely dense and hard; not a typical flooring choice | | Ipe | 3,680 lbf | 16,370 N | Very hard tropical wood often used for decking |

Common names can create confusion. “Brazilian cherry” is jatoba and is not closely related to American black cherry. Likewise, products sold as acacia, mahogany, or ironwood may come from several species with very different properties.

Some charts also list bamboo, but bamboo is a grass rather than wood. Its hardness depends heavily on manufacturing, strand compression, heat treatment, and adhesive. A single bamboo rating cannot represent every bamboo flooring product.

What does Janka hardness mean for flooring?

Janka hardness helps estimate how readily a floor may dent under concentrated loads. A harder species may be useful in an active household with large dogs, rolling furniture, high heels, or frequently dropped objects. It does not make a floor damage-proof.

Red oak at about 1,290 lbf is often treated as a practical reference point in the North American flooring market. Black walnut, at about 1,010 lbf, is softer and can develop dents sooner. Hard maple and hickory provide greater indentation resistance, while woods such as jatoba and ipe are much harder.

Hardness should not be the only flooring criterion. Consider these factors as well:

• Finish performance: The finish often receives scratches before the wood fibers are deeply dented.
• Dimensional stability: A hard wood can still expand, shrink, cup, or gap as humidity changes.
• Grain visibility: Open or varied grain can make small marks less noticeable than a smooth, uniform surface.
• Board construction: Engineered flooring may be more dimensionally stable, but its wear layer still has the hardness of the surface species.
• Installation difficulty: Very hard woods can require predrilling, sharp blades, and careful nailing.
• Color change: Cherry, walnut, jatoba, and many other woods can change color with light exposure.
• Repair options: A solid floor may allow multiple sandings, while a thin veneer limits refinishing.

A low rating does not automatically disqualify a species. Pine floors have been used for centuries and often develop a visible patina. If dents and wear are acceptable, softer flooring can be a deliberate aesthetic choice.

Hardness also does not equal scratch resistance. Sand, pet claws, and furniture movement can scratch a coating or abrade the surface. Entry mats, felt pads, trimmed claws, and routine cleaning may have more effect on visible scratching than choosing a species a few hundred points higher on the scale.

How should furniture makers use Janka ratings?

For furniture, the ideal hardness depends on the part and the intended use. A dining tabletop benefits from dent resistance, but a chair also needs suitable strength, grain orientation, joint design, and dimensional stability. A decorative carving may be easier and cleaner in a softer, fine-grained wood.

Hard maple is useful for work surfaces, butcher blocks, drawer sides, and other parts that receive repeated contact. White oak offers good hardness and prominent grain. Walnut is softer than either species, yet it remains a respected furniture wood because it machines well, finishes attractively, and provides adequate strength for many designs.

Extremely hard wood can introduce practical problems. It may dull cutting edges, burn during routing, resist nails and screws, or split when fasteners are installed without pilot holes. Dense tropical species can also contain oils or extractives that affect gluing and finishing. Test cuts and finish samples are sensible before building a full project.

Softer woods have their own advantages. Basswood supports detailed carving because it cuts easily and has subtle grain. Pine is easy to shape and widely used for painted furniture. Alder machines readily and can take stain, although blotching may need to be controlled.

For a furniture project, ask four questions:

1. Will the surface receive concentrated impacts or only light handling?
2. Does the design require carving, bending, turning, or crisp routed profiles?
3. Will seasonal movement be more important than dent resistance?
4. Are available tools suitable for the wood’s density and hardness?

A harder species is not automatically the better material. The most suitable wood balances appearance, workability, stability, strength, availability, and expected wear.

Can hardness help identify an unknown wood?

Hardness can narrow a list of candidates, but it rarely identifies a species by itself. If an unknown board dents very easily under light pressure, extremely hard candidates become less likely. If it rapidly dulls tools and strongly resists indentation, soft pine, basswood, and similar woods become less likely.

Informal testing is subjective. A fingernail test depends on the person, nail shape, pressure, grain direction, moisture content, and surface finish. Testing with a knife or awl damages the sample and still does not reproduce a standardized Janka result. Do not perform destructive tests on valuable furniture, antiques, flooring, or finished objects.

Use hardness alongside more diagnostic features:

• End-grain pore arrangement and size
• Growth-ring boundaries
• Rays, including the broad rays found in oak
• Grain direction and figure
• Heartwood and sapwood color
• Weight relative to board size
• Odor from a fresh cut, when safe to obtain
• Resin, gum, or oily extractives
• Geographic origin and intended use

End grain often carries more useful anatomical evidence than hardness. Ring-porous woods such as oak and ash show large earlywood pores, while maple and birch have much smaller, more evenly distributed pores. The end grain identification guide explains how to prepare and photograph this surface.

Photo analysis can then compare visible grain and color clues. The Wood Identifier provides an AI-assisted starting point for lumber, furniture, firewood, and grain analysis. Its result should still be checked against anatomy, hardness range, provenance, and other physical evidence.

For a broader process, follow the step-by-step wood identification guide. Good identification is based on several clues agreeing, not one measurement appearing to fit.

Why do Janka hardness values vary between charts?

Two credible charts may publish different figures for the same named wood. Wood is a biological material, so natural variation is unavoidable. Test standards and reporting choices can add further differences.

Important sources of variation include:

• Moisture content: Higher moisture usually reduces hardness.
• Growth rate and site: Soil, climate, and competition affect wood formation.
• Sample position: Heartwood, sapwood, juvenile wood, and mature wood may differ.
• Grain angle: Sloping grain can respond differently from straight grain.
• Test surface: Side hardness and end hardness are not directly interchangeable.
• Species naming: A trade name may cover several botanical species.
• Data method: A chart may report a mean, rounded value, or figure copied from another source.

Regional species differences matter too. “Southern yellow pine” can refer to several species. Longleaf pine is commonly listed near 870 lbf, but other pines sold under the broader label may have different values. Hard maple usually refers to sugar maple or black maple, while soft maple can include red or silver maple and generally has lower hardness.

Treat small ranking differences cautiously. A listed difference of 50 or 100 lbf may not be noticeable in a finished product, especially when individual boards overlap in their real properties. Larger differences, such as white pine compared with hickory, are more useful for practical decisions.

Frequently asked questions

Is a higher Janka rating always better?

No. A higher rating usually means better resistance to indentation, but it can also mean more difficult machining, fastening, sanding, and installation. Softer woods may be preferable for carving, hand-tool work, painted furniture, or floors intended to develop patina.

What Janka hardness is good for flooring?

There is no universal minimum. Red oak at about 1,290 lbf is a common reference because it has a long history as residential flooring. Softer species can perform well when dents are acceptable, while harder species may suit areas exposed to concentrated impacts. Finish, maintenance, stability, and board construction also matter.

Does the Janka test measure scratch resistance?

No. It measures the force required to make a standardized indentation. Scratching is affected by finish chemistry, abrasive particles, surface texture, and the object causing the scratch. A very hard wood can still have a scratched coating.

Can I perform a Janka test at home?

A standardized result requires a suitable steel ball, controlled loading equipment, prepared samples, and known test conditions. Home comparisons with a nail, awl, or ball bearing may indicate that one sample is softer than another, but they do not produce reliable published Janka values.

Is hardwood always higher on the scale than softwood?

No. Hardwood and softwood are botanical categories, not direct hardness grades. Balsa is a hardwood but is extremely soft. Some softwoods, including denser southern yellow pines, are harder than certain hardwood species. See hardwood vs softwood identification for the anatomical distinction.

Can Janka hardness confirm a wood species?

Usually not. Many unrelated species have overlapping ratings, and individual samples vary. Hardness works best as an exclusion or supporting clue. Combine it with end grain, pores, rays, color, density, odor, provenance, and a clear photograph.

Identify wood with AI

When you have an unknown board, floor, furniture part, or firewood sample, photograph a clean grain surface in soft, even light. Include end grain when possible and avoid glare, stain, or heavy finish. These wood photography tips for AI identification can improve the visible evidence.

Use the Wood Identifier iOS app to compare the photo with likely species, then check the suggested species against its Janka range and anatomical features. Download Wood Identifier on the App Store.