I created this Janka Hardness Scale/Chart because in my own experiences of searching for the Janka Hardness of different woods it took some time of searching through books, documents, papers and on the WWW to find the information. Also the hardness was different from different sources, the botanical/scientific names were only partially listed, not listed at all or in some instances incorrect. I thought it would be nice to have them all listed in one spot and as correct as possible.

This is an ongoing work in progress! There are already countless hours of research that have gone into the 9 pages to get the results as accurate as possible. I still have several woods to research and add. The world's top 125 known softest and hardest woods lists may have minor changes made to them from time to time. I will be updating the page frequently. I hope the information will be of value and helpful to others.

I give permission to link to this page from other websites and forums. The URL address for this page is http://www.morlanwoodgifts.com/MM011.ASP?pageno=209 If you copy some of the information to put on a website or forum, all that I ask of you is to acknowledge me as the author.

You are more than welcome to use the converters below from pounds of force {lbf} to kilograms of force {kgf}, kilonewtons {kN} and newtons {N}.

The main compression/indentation tests used to measure the hardness of wood are Brinell {steel ball}, Chalais-Meudon {Monnin} {steel cylinder}, Janka {steel ball}, Meyer {steel ball}, Piazza-Turrini {steel ball} and Pilodyn {steel pin}.

Brinell, Chalais-Meudon {Monnin} and Janka are the three most used. With very few minute differences all three list woods in the same hardness order. By far Janka is used the most often and has the most test results available. I will briefly touch on the Brinell and Chalais-Meudon {Monnin} tests.

The Brinell Hardness Test was invented in 1900 by the Swedish mechanical engineer and metallurgist Johan August Brinell {1849 - 1925}. It was first used to only test metals but has since been altered to also test woods. With metal a tungsten or carbide ball is used.

For wood a harden steel ball with a diameter of 10 millimeters {approximately 13/32 of an inch} is pressed into the wood with the pressure {force} of 1 kilonewton, approximately 102 kilograms or 224 pounds 12 3/4 ounces}. Then it is held there for a specified time called the dwell time and is usually from 10 - 30 seconds. The diameter of the indentation is measured with a low powered microscope or a computer optical system. It is calculated as a ratio of pressure {force} to the curved surface of the indentation using the below equation.

With wood the Brinell hardness results are either given with one number like 1.6, 2.2, 4.1 etcetera or with 2 numbers {low and high} such as 4.7 - 5.1. The correct way is to list the Brinell hardness number, the type of ball used, the diameter of the ball, the amount of force applied and the amount of time. Ash would be listed as 4.1 HBS 10/100/30 which means the Brinell hardness of Ash is 4.1 when a hardened steel ball that is 10 millimeters in diameter is pressed into it with the pressure {force} of 100 kilograms for 30 seconds.

The Chalais-Meudon {Monnin} Hardness Test was invented in the early 1920's by the Frenchman Marcel Monnin {1877 - 1944}. He was the manager of a water and forest engineering school which was located in Chalais-Meudon a suburb of Paris, France. He was actually the initiator for the physical and mechanical methods of testing wood.

A steel cylinder with a diameter of 30 millimeters {approximately 1 11/64 of an inch or the diameter of an American half dollar} is pressed into the wood with the pressure {force} of 200 daN {dekanewtons} which is {2 kilonewtons, approximately 204 kilograms or 449 pounds 9 1/2 ounces} for 5 seconds.

Because it is almost impossible to get a precise measurement of the depth {t} of the indentation that the cylinder made, only the width {l} in millimeters is measured and then calculated from the below equation. The Monnin hardness is then said to be the reciprocal of the depth of the indentation. HM equals 1/t. Monnin hardness results are either given with one number like 1.3, 2.7, 4.8 etcetera or with 2 numbers {low and high} such as 3.2 - 4.6.

The Janka Hardness Test was invented in 1906 by Gabriel Janka {1864 - 1932}. He was an Austrian wood researcher. In 1906 at the age of 42 he wrote the 40 page book, Die Harte Des Holzes {translated is} The Hardness Of The Wood.

The Janka Hardness Test measures how hard wood/lumber/timber is. The higher the number the harder the wood is. It is an adaptation of the Brinell Hardness Test for metals.

It is probably the best way to determine how durable a particular wood species is. How easy or difficult it will crush or mash under loads, dent, ding, mar or scratch. This is extremely important if you are using solid wood for certain applications such as interior flooring, exterior decking, porch flooring, stair treads, stair landings, tabletops, desktops, kitchen and workbench countertops.

It is very important to percussion instrument makers {drums etcetera}, woodwind instrument makers {flutes etcetera} and stringed instrument makers Luthiers {guitars etcetera} because a certain hardness produces a particular distinctive tone. The softer the wood the more sound it absorbs thus making the sound tone quieter and mellower. The harder the wood the less sound it absorbs thus making the sound tone louder and sharper. Also with Luthiers certain parts such as necks and bridges are made from a certain hardness of wood.

It is also a very good indicator of how easy or difficult a particular wood species will be to nail, screw, sand, saw, plane, route, carve, polish and work in general.

The results of the original test were indicated in units of pressure required to drive in a steel ball with a diameter of 11.28 millimeters {approximately 31/64 inches} into the wood to half its diameter. This procedure was chosen so that the result would leave an indentation of exactly 100 square millimeters {approximately 9/64 square inches} in size. When the American Society for Testing and Materials {ASTM} standardized the test in 1927 it called for the results to be indicated in units of force.

Now in the English measurement system, the result is indicated in pounds of force per square inch {lbf/in2}. In the Metric measurement system, the result is indicated in one of three ways, kilograms of force per square centimeter {kgf/cm2}, kilonewtons {kN} or newtons {N}.

The hardness of wood/lumber/timber usually varies with the direction of the wood grain. When testing is done on the tangential and radial surface of a piece of wood with the force applied perpendicular to the grain, the test is of side hardness. All Janka Hardnesses listed on this website are of side hardness.

Testing is done on wood from the trunk of the tree and is almost always the heartwood. With heartwood there are a handful of exceptions. One that comes to mind is Balsa {Ochroma pyramidale}. Balsa is always milled from sapwood.

The standard sample as indicated in ASTM D 1043 is to be at 12% moisture content, be clear {no knots}, a solid block of wood having the dimensions of at least 2" x 2" x 6" long and the rate of loading will be machine set at 1/4" per minute.

Two indentations are made on the tangential surface and two indentations on the radial surface. The four indentations are then added together and divided by 4 to get the average value of the force, with the result being declared as the side hardness.

When testing is done on a piece of wood with the force applied to the end grain surface, the test is of end hardness. The end hardness of wood/lumber/timber will almost always be higher {harder} than its side hardness. There are exceptions. Examples would be,

Most wood/lumber/timber species will deviate in hardness but not by much more than plus or minus 10% of the chart numbers below from one piece of wood/lumber/timber to another or wood coming from two different geographical locations. With geographical locations there are exceptions. Examples would be,

Also the wood/lumber/timber around knots, having interlocked grain, at less than 12% moisture content and burl wood will be harder than the chart numbers below which are of average side hardness with the wood at 12% moisture content.

Trees can be classed or grouped in several ways. The wood/lumber/timber industry uses two broad/generic classes or groups for the wood/lumber/timber that comes from trees, they are hardwood and softwood.

Hardwood comes from {Deciduous} angiosperms which are broadleaved and are either catkin bearing or flower bearing trees. Softwood comes from trees belonging to the order Coniferales/Coniferous gymnosperms which are cone bearing or evergreen and have needle or scale like leaves. There are exceptions! Some examples would be,

Balsa {Ochroma pyramidale} Janka Hardness 88 and Basswood {Tilia americana} Janka Hardness 410 are Deciduous and are extremely soft.

Yew Pacific {Taxus brevifolia} Janka Hardness 1600 is in the order Coniferales/Coniferous and is harder than Ashes {Fraxinus spp.}, Birches {Betula spp.}, Maples {Acer spp.}, Oaks {Quercus spp.} or Walnuts {Juglans spp.}.

Not all species of wood/lumber/timber have had a Janka Hardness test performed on them and there are species that have had the Janka Hardness test performed on them but the results are not publicly published.

Because of the moisture content of wood/lumber/timber it has 2 specific gravities, the what I call density specific gravity and basic specific gravity which is also referred to as basic density. Both are figured differently. All specific gravities listed on this website are density specific gravities.

Density specific gravity is the ratio of density of a substance compared to the density of fresh water when it is at its greatest value which is 4 degrees Celsius, {39.2 degrees Fahrenheit}.

With wood/lumber/timber to figure the density specific gravity you take the kg/m3 {kilograms per cubic meter weight} at 12% moisture content {industry standard} and divide it by 1000. That is the density specific gravity and will tell you whether the wood/lumber/timber will float or sink in water. To float in water wood/lumber/timber has to weigh less than 1,000 kg/m3.

At 12% moisture content if any wood/lumber/timber had no air spaces or pockets in it, the highest possible density specific gravity it could have would be 1.52. The highest possible weight would be 1520 kilograms per cubic meter {kg/m3}, 3350 pounds per cubic meter {m3}, 94 pounds 14 ounces per cubic foot {lb/ft3} or almost 5 pounds 15 ounces per board foot {bf} {planed/dressed out} 12" x 12" x 3/4" thick.

Basic specific gravity is calculated by oven dry mass {weight} divided by wet {green} volume and is always lower than density specific gravity. Basic specific gravity is not at all accurate in telling you whether the wood/lumber/timber will float or sink in water. A few examples would be,

With wood/lumber/timber as a general rule the more it weighs, the denser it is and the higher specific gravity it has the harder it is. Weight/density/specific gravity and hardness with some wood/lumber/timber species are different.

Wood/lumber/timber species that have more oils, gums, resins and less lignum {gives hardness to wood} cells in them are softer sometimes than the weight/density/specific gravity indicates they are. This is because the oil, gum and resin mixed in with the wood fibers makes the wood heavy but yet in a compression test such as Janka makes the wood softer. An example would be,

Wood/lumber/timber species that have less oils, gums, resins and more lignum {gives hardness to wood} cells in them are harder sometimes than the weight/density/specific gravity indicates they are. An example would be,

There are no formulas or computations to figure/convert Janka Hardness to specific gravity or vice versa! A particular Janka Hardness does not have a certain specific gravity or vice versa! An example would be,

At the very least common/trade names can be bewildering. It is somewhat better and if at all possible to get the botanical/scientific name of a species. What is vastly unknown though, is a tree species can have more than one botanical/scientific name. For more information and details, see Note 7.

A species can have different common/trade names in different locations. An example would be the botanical/scientific name of {Hyeronima alchorneoides} with a Janka Hardness of 1700. It has the common/trade names of,

The same common/trade name can be given to more than one wood/lumber/timber species either having a completely different Genus {the first name in a botanical/scientific name} or having the same Genus but a different species name {the second name in a botanical/scientific name}. An example having a completely different Genus would be, botanical/scientific name {Astronium graveolens} with a Janka Hardness of 2160 & botanical/scientific name {Lovoa trichilioides} with a Janka Hardness of 940. Both are sold by the common/trade name of Tigerwood.

An example having the same Genus but a different species name would be, botanical/scientific name {Peltogyne confertiflora} with a Janka Hardness of 3820, {Peltogyne paniculata} with a Janka Hardness of 2710, botanical/scientific name {Peltogyne porphyrocardia} with a Janka Hardness of 2430 & botanical/scientific name {Peltogyne venosa} with a Janka Hardness of 2030. Although all four have different Janka Hardness's, vary in color and weight they are sold by the common/trade name of Purpleheart.

Sometimes the wood flooring industry gives their own made up common/trades names to the wood/lumber/timber species they sell as flooring. Examples would be,

Some common/trade names can indicate that a wood/lumber/timber species belongs to a certain group {Genus} when actually it is not even a member of that group {Genus}. Examples would be,

Botanical/scientific names can and do change. Ongoing study of a tree may show the tree to have been wrongly classified and with new information be reclassified in a different family, genus or species. To change a trees botanical/scientific name is not easy. The rules are set forth by the International Code of Nomenclature for Cultivated Plants, {ICNCP}.

A tree may have had other botanical/scientific names over the years, but has only one botanical/scientific up to date accepted name which is recognized worldwide! The previous old outdated names are called synonyms. Botanical/scientific name synonyms are not interchangeable like the standard usage of the word synonym. Botanical/scientific name synonyms are not to be used as a substitute for the up to date accepted name! Of course the old outdated names may stay around for years because it is very hard to keep up with all the name changes. A few examples would be,

The wood/lumber of Sheoak Forest, with the Janka Hardness of 3150 has the up to date accepted botanical/scientific name of {Allocasuarina torulosa}.

The wood/lumber of Louro Vermelho, with the Janka Hardness of 660 has the up to date accepted botanical/scientific name of {Sextonia rubra}.

The wood/lumber of, Kapok with the Janka Hardness of 240 has the up to date accepted botanical/scientific name of {Ceiba pentandra}.

The wood/lumber of the Brazilian Fire Tree, with the Janka Hardness of 450 has the up to date accepted botanical/scientific name of {Schizolobium parahybum}.

The wood/lumber of Ebony Texas, with the Janka Hardness of 2570 has the up to date accepted botanical/scientific name of {Ebenopsis ebano}.

The wood/lumber of Monkey Pod, with the Janka Hardness of 850 has the up to date accepted botanical/scientific name of {Samanea saman}.

The wood/lumber of Tamarind Wild, with the Janka Hardness of 1400 has the up to date accepted botanical/scientific name of {Cojoba arborea}.

To use converter, type in a number in the top Pounds Force {lbf} box. All numbers are in pounds of force {lbf} on this page. The converted result will automatically appear in the Kilograms Force {kgf} box, Kilonewtons {kN} box and the Newtons {N} box.