The Janka Hardness Scale is determined by a controlled test, performed to measure the force necessary to embed a .444 inch (11.28mm) steel ball to half its diameter in wood.  The resulting data is expressed in pounds-force, or lbf.  This industry standard assessment is designed to gauge the various wood species hardness, determine its suitability as flooring, and illustrate its tolerance to normal wear, tear and dents.

The Janka hardness scale is also an excellent indicator of the effort required to drive a nail through a particular type of wood.  In essence, the higher the number on the scale, the harder the wood.

When selecting hardwood floors, consider your home or office layout and traffic patterns.  If you have children or animals, very soft wood like pine may not be desirable.  All wood species below Red Oak on the Janka scale are expected to dent or wear more easily, but offer warmth and charm as they age.  Extremely dense and exotic woods, however, are reputed for being exceptionally hard.  While these species may offer benefits in high-traffic homes and offices, they can be challenging to install or require temperature controlled environments.

Wood Flooring Species Hardness
Ipe / Brazilian Walnut / Lapacho 3684
Cumaru / Brazilian Teak 3540
Ebony 3220
Strandwoven Bamboo 3200
Brazilian Redwood / Paraju 3190
Angelim Pedra 3040
Bloodwood 2900
Red Mahogany 2697
Spotted Gum 2473
Brazilian Cherry  / Jatoba 2350
Mesquite 2345
Santos Mahogany, Bocote, Cabreuva 2200
Pradoo 2170
Tigerwood 2160
Brushbox 2135
Karri 2030
Sydney Blue Gum 2023
Bubinga 1980
Pyinkado 1950
Cameron 1940
Tallowwood 1933
Merbau 1925
Amendoim 1912
Jarrah 1910
Moabi (Pearwood, African) 1900
Purpleheart 1860
Goncalo Alves / Tigerwood 1850
Hickory / Pecan, Satinwood 1820
Afzelia / Doussie 1810
Bangkirai 1798
Rosewood 1780
Acacia (Acacia mangium) (Dried to 12% Moisture for Flooring) (Wild Walnut) 1750
African Padauk 1725
Blackwood 1720
Merbau 1712
Kempas 1710
Locust 1700
Highland Beech 1686
Wenge, Red Pine 1630
Tualang 1624
Zebrawood 1575
True Pine, Timborana 1570
Peroba 1557
Kambala 1540
Sapele / Sapelli 1510
Curupixa 1490
Sweet Birch 1470
Hard Maple / Sugar Maple 1450
Coffee Bean 1390
Natural Bamboo (represents one species) 1380
Australian Cypress 1375
White Oak 1360
Tasmanian Oak 1350
Ribbon Gum 1349
Ash (White) 1320
American Beech 1300
Red Oak (Northern) 1290
Acacia (Acacia mangium) Green Material 1280
Carribean Heart Pine 1280
Yellow Birch 1260
Movingui 1230
Heart Pine 1225
Carbonized Bamboo  (represents one species) 1180
Cocobolo 1136
Brazilian Eucalyptus / Rose Gum 1125
Makore 1100
Boreal 1023
Black Walnut 1010
Teak 1000
Sakura 995
Hevea (rubberwood brazili) 995
American Cherry 950
Black Cherry, Imbuia 950
Boire 940
Paper Birch 910
Cedar 900
Southern Yellow Pine (Longleaf) 870
Lacewood, Leopardwood 840
Parana 780
Sycamore 770
Shedua 710
Southern Yellow Pine (Loblolly and Shortleaf) 690
Douglas Fir 660
Larch 590
Chestnut 540
Hemlock 500
White Pine 420
Basswood 410
Eastern White Pine 380

Photo Credits
Janka Hardness Test – Wiki Images