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Janka hardness test being performed on Ipe hardwood

Janka Hardness Scale

The industry-standard measure of wood surface hardness — compare 36 species from softwoods to the world's hardest timbers.

3,684

Ipe (lbf)

1,290

Red Oak (lbf)

350

Cedar (lbf)

2.9×

Ipe vs Red Oak

Wood Hardness Guide

Janka Hardness Scale

Compare wood durability at a glance — from softwoods to the world's hardest decking timbers

2.9×

harder

Ipe vs Red Oak

11×

harder

Ipe vs Cedar

18×

harder

Ipe vs Composite

75+

years

Ipe Lifespan

Hardness Comparison

Pounds-force (lbf) — higher = harder & more durable

1
IpeWe Sell
3,684 lbf
Decking Min
Floor Min
2
CumaruWe Sell
3,540 lbf
3
MassarandubaWe Sell
3,190 lbf
4
Red BalauWe Sell
2,700 lbf
5
TigerwoodWe Sell
2,170 lbf
6
GarapaWe Sell
1,650 lbf
7
White Oak
1,360 lbf
8
Red Oak
1,290 lbf
9
Teak
1,155 lbf
10
Southern Yellow Pine
690 lbf
11
Western Red Cedar
350 lbf
12
Trex Composite
200 lbf

Why Ipe Leads the Chart

3,684 lbf Janka Class A Fire Rot Resistant Insect Proof
Learn More
Source: USDA Forest Products Laboratory Wood Handbook, ASTM D143IpeWoods.com

What Is the Janka Hardness Test?

The Janka hardness test (ASTM D143) measures the force in pounds-force (lbf) required to embed a 0.444-inch (11.28 mm) steel ball to half its diameter into a wood sample. Developed by Austrian researcher Gabriel Janka and standardized by the USDA Forest Products Laboratory, it is the most widely used benchmark for comparing wood hardness worldwide.

Higher Rating = Harder Wood

More resistant to dents, scratches, and wear. Ideal for high-traffic decking, flooring, and outdoor applications.

Not the Only Factor

Hardness doesn't measure rot resistance, dimensional stability, fire rating, or workability. Always consider the full picture.

How the Janka Hardness Test Works

The Janka test, codified as ASTM D143 Standard Test Methods for Small Clear Specimens of Timber, uses a hydraulic press to force a 0.444-inch (11.28 mm) diameter steel ball into the surface of a conditioned wood sample until the ball is embedded to half its diameter. The force required to achieve this penetration — measured in pounds-force (lbf) — is the Janka rating.

Two measurements are typically taken: side hardness (perpendicular to the grain) and end hardness (parallel to the grain). Side hardness is the standard comparison metric because it represents the wearing surface of flooring and decking boards. End hardness is usually 20–30% higher but is less relevant for everyday use.

Wood samples are conditioned to 12% moisture content before testing, as moisture significantly affects hardness readings. Wetter wood tests softer; kiln-dried wood tests harder. This standardization ensures consistent, comparable results across species and laboratories worldwide.

Steel Ball Size

0.444"

11.28 mm diameter

Penetration Depth

50%

Half the ball's diameter

Moisture Content

12%

Standard conditioning

Recommended Janka Ratings by Application

Different projects demand different levels of hardness. Here's what professionals recommend based on decades of real-world performance data.

Decking

1,500+ lbf

Outdoor decks endure UV, rain, foot traffic, and furniture. Hardwoods above 1,500 lbf resist denting and surface wear for decades.

Top picks: Ipe, Cumaru, Tigerwood

Shop Decking

Interior Flooring

1,000+ lbf

High-traffic floors need scratch resistance. Red Oak (1,290 lbf) is the industry benchmark — anything higher is considered premium.

Top picks: Red Oak, White Oak, Hickory

Fencing

1,200+ lbf

Privacy fences take impact and weather exposure. Hardwoods above 1,200 lbf resist warping, splitting, and insect damage far better than softwoods.

Top picks: Ipe, Cumaru, Garapa

Shop Fencing

Siding & Cladding

1,500+ lbf

Exterior cladding needs impact resistance and dimensional stability. Dense tropical hardwoods maintain their profile over decades.

Top picks: Ipe, Cumaru, Massaranduba

Shop Siding & Cladding

Complete Hardness Table

#SpeciesJanka (lbf)
1
Australian Buloke
5,060lbf
2
Quebracho
4,800lbf
3
Lignum Vitae
4,500lbf
4
Curupay
3,840lbf
5
Snakewood
3,800lbf
6
Brazilian Ebony
3,700lbf
7
Ipe(Brazilian Walnut)
We Sell
3,684lbf
8
Grey Ironbark
3,664lbf
9
Bolivian Cherry
3,650lbf
10
Cumaru(Brazilian Teak)
We Sell
3,540lbf
11
Sucupira
3,417lbf
12
Ironwood
3,260lbf
13
Massaranduba(Brazilian Redwood)
We Sell
3,190lbf
14
Strand Woven Bamboo
3,000lbf
15
Cocobolo
2,960lbf
16
Red Balau(Batu)
We Sell
2,700lbf
17
Live Oak
2,680lbf
18
Spotted Gum
2,473lbf
19
Brazilian Cherry(Jatoba)
2,350lbf
20
Mesquite
2,345lbf
21
Tigerwood(Goncalo Alves)
We Sell
2,170lbf
22
Hickory
1,820lbf
23
Pecan
1,820lbf
24
Garapa(Brazilian Ash)
We Sell
1,650lbf
25
Hard Maple
1,450lbf
26
White Oak
1,360lbf
27
Ash
1,320lbf
28
Red Oak
1,290lbf
29
Teak
1,155lbf
30
Black Walnut
1,010lbf
31
Black Cherry
950lbf
32
Southern Yellow Pine
690lbf
33
Douglas Fir
660lbf
34
Eastern White Pine
380lbf
35
Western Red Cedar
350lbf
36
Trex Composite
Composite
200lbf

Source: USDA Forest Products Laboratory Wood Handbook, ASTM D143. Composite value is estimated penetration resistance for comparison only.

Frequently Asked Questions

What is the Janka hardness test?
The Janka hardness test measures the force (in pounds-force, lbf) required to embed a 0.444-inch steel ball halfway into a piece of wood. It is the industry standard for comparing the surface hardness and wear-resistance of different wood species, established by the USDA Forest Products Laboratory under ASTM D143.
What is a good Janka rating for a deck?
For outdoor decking, a Janka rating of 1,500 lbf or higher is recommended. Premium tropical hardwoods like Ipe (3,684 lbf) and Cumaru (3,540 lbf) offer exceptional scratch and dent resistance that far exceeds domestic options like Red Oak (1,290 lbf) or softwoods like Cedar (350 lbf).
How does Ipe compare to composite decking on the Janka scale?
Ipe rates 3,684 lbf on the Janka scale — roughly 18× harder than composite decking materials (~200 lbf equivalent). While composites are low-maintenance, they dent, scratch, and fade much more easily than Ipe. Ipe also naturally resists fire (Class A rated), rot, and insects without chemical treatment.
Does a higher Janka rating mean the wood is better?
Not necessarily. Janka measures surface hardness only — it doesn't account for dimensional stability, workability, moisture resistance, or appearance. A very hard wood like Ipe is excellent for decking but requires carbide tooling and pre-drilling. The best species for your project depends on the application, climate, and desired aesthetic.
What is the hardest wood in the world?
Australian Buloke (Allocasuarina luehmannii) holds the record at 5,060 lbf, but it is not commercially available as lumber. Among commercially available decking woods, Ipe (3,684 lbf) and Cumaru (3,540 lbf) are the hardest options.
What Janka rating is best for hardwood flooring?
For interior hardwood flooring, a Janka rating of at least 1,000 lbf is recommended. High-traffic areas benefit from ratings above 1,300 lbf. Red Oak (1,290 lbf) is the traditional benchmark — anything harder is considered above average for flooring use.
Is the Janka test the same for all wood orientations?
No. The standard Janka test measures hardness perpendicular to the grain (side hardness), which is the most relevant for flooring and decking wear. End-grain hardness is typically higher but is not the standard measurement used for comparisons.
Can you compare composite decking to real wood on the Janka scale?
Not directly — composites are not solid wood and are not tested using the ASTM D143 standard. However, estimated penetration resistance of composites like Trex is roughly 200 lbf equivalent, making them significantly softer than even the softest real woods used in decking.
Why do tropical hardwoods score so much higher than domestic species?
Tropical hardwoods like Ipe, Cumaru, and Massaranduba grow slowly in dense rainforest canopies, developing extremely tight grain structures and high density. This results in Janka ratings 2–5× higher than domestic species like oak or maple, plus superior natural resistance to rot, insects, and fire.
Does Janka hardness affect how a deck weathers?
Indirectly, yes. Harder woods resist surface erosion from UV exposure, foot traffic, and moisture better than softer species. Ipe decking, for example, can last 75+ years outdoors with minimal maintenance, while softer woods like cedar (350 lbf) may show wear in 10–15 years.

Tropical Hardwoods vs. Domestic Species: Why the Gap?

The most striking feature of the Janka scale is the massive gap between tropical and domestic hardwoods. Ipe (3,684 lbf) is nearly 3× harder than Red Oak (1,290 lbf), the traditional benchmark for American hardwood flooring. Why such a dramatic difference?

Tropical species like Ipe, Cumaru, and Massaranduba grow in the dense canopy layers of South American rainforests, where competition for light drives extremely slow growth over 80–120 years. This slow growth produces exceptionally tight grain patterns and high specific gravity (Ipe's density averages 69 lbs/ft³ vs. Red Oak's 44 lbs/ft³). The result is wood that resists surface wear, insect attack, and decay without any chemical treatment.

For outdoor applications like decking, siding, and fencing, this natural durability translates directly into longer lifespan and lower lifetime cost. An Ipe deck can last 75+ years with minimal maintenance, while a pressure-treated pine deck (690 lbf) typically needs replacement in 10–15 years — meaning Ipe can be the more economical choice over time despite a higher upfront cost.

Key Takeaway for Buyers

If your project is outdoors and exposed to weather, foot traffic, or UV — look for species above 1,500 lbf on the Janka scale. For the longest-lasting investment, tropical hardwoods in the 2,000–3,700 lbf range deliver unmatched performance. See current pricing →

Ready to Choose Your Hardwood?

Our team can help you pick the perfect species for your project's demands.