# Janka Hardness Ratings for Selected Woods

Contents

The Janka hardness ratings are useful in determining how well a wood species will withstand dents, dings, and wear—as well as indirectly predicting the difficulty in nailing, screwing, sanding, or sawing.

The numbers listed in the table below is the amount of pounds-force (lbf), kilogram-force (kgf), or newtons (N) required to embed a .444 inch (11.28 mm) diameter steel ball into the wood to half the ball’s diameter. That particular diameter was chosen to produce a circle with an area of 100 square millimeters. The numbers are given for wood that has been dried to a 12% moisture content, unless otherwise noted.

The Janka hardness ratings are stated in different ways in different countries, leading to confusion as the name of the actual unit used is often not given. While in the United States the measurement is in pounds-force (lbf), in Sweden, for example, it is in kilograms-force (kgf), and in Australia it is in either newtons (N) or kilonewtons (kN). Sometimes the Janka hardness ratings are used as units themselves, e.g., “360 janka”.

The relationship between the different units are:

Unit Conversion (Approx) Example
lbf kgf   ×   2.2046 1221 lbf   =   554 kgf   ×   2.2046
lbf N   ×   0.22481 1221 lbf   =   5,430 N   ×   0.22481
kgf lbf   ×   0.45359 553 kgf   =   1220 lbf   ×   0.45359
kgf N   ×   0.10197 554 kgf   =   5430 N   ×   0.10197
N lbf   ×   4.448222 5,427 N   =   1220 lbf   ×   4.448222
N kgf   ×   9.80665 5433 N   =   554 kgf   ×   9.80665

The conversion factors are approximations that are good enough for day-to-day use—you may have noticed the rounding errors in the examples. In the table below, where the kgf value is unknown it is calculated using the lbf value or if the lbf value is unknown, it is calculated using the N value.

Name(S) lbf kgf N Notes
Hard Maple (Acer saccharum)
Sugar Maple
Rock Maple
1,450 658 6,450
White Oak (Quercus alba) 1,350 612 5,990
Red Oak (Quercus rubra) 1,220 554 5,430
Black Walnut (Juglans nigra) 1,010 458 4,490
Bigleaf Maple (Acer macrophyllum) 850 386 3,780 A soft maple.
American Elm (Ulmus americana)
Soft Elm
Water Elm
830 376 3,690
Douglas-Fir (Pseudotsuga menziesii) 620 281 2,760
Poplar (Liriodendron tulipifera)
Tulip Poplar
Yellow Poplar
540 245 2,400
Ponderosa Pine (Pinus ponderosa) 460 209 2,050
Redwood (Sequoia sempervirens)
Sequoia
Coast Redwood
California Redwood
Vavona (burl)
450 204 2,000
Basswood (Tilia americana)
American Basswood
Lime
Linden
410 186 1,824
Balsa (Ochroma pyramidale) 90 41 390

## Wood Groups

### White Oak

Name(S) lbf kgf N Notes

### Red Oak

Name(S) lbf kgf N Notes

### Soft Pine

Name(S) lbf kgf N Notes
Eastern White Pine (Pinus strobus) 380 1,690 Finest texture (i.e., smallest diameter tracheids) and the smallest resin canals.
Limber Pine (Pinus flexilis) 430 1,910 Not commonly used.
Sugar Pine (Pinus lambertiana) 380 1,690 Coarsest texture and the largest resin canals.
Western White Pine (Pinus monticola)
Idaho White Pine
420 1,870

### Hard Pine

#### Southern Yellow Pine

Southern Yellow Pine is mentioned in a lot of YouTube videos, usually from people in the eastern part of the country. It doesn’t seem to be as commonly available in the western part.

Name(S) lbf kgf N Notes
Major Species
Loblolly Pine (Pinus taeda) 690 3,070
Longleaf Pine (Pinus palustris) 870 4,120
Shortleaf Pine (Pinus echinata) 690 3,070
Slash Pine (Pinus elliotti) 760 3,380
Minor Species
Pitch Pine (Pinus rigida) 620 2,760
Pond Pine (Pinus serotina) 740 3,290
Sand Pine (Pinus clausa) 730 3,250
Spruce Pine (Pinus glabra) 700 3,110
Table Mountain Pine (Pinus pungens) 730 3,250
Virginia Pine (Pinus virginiana) 740 3,290
Miscellaneous
Caribbean Pine (Pinus caribaea) 1,110 4,920 Commonly grown on plantations. Nearly identical to the four major species of Southern Yellow Pine.

#### Western Yellow Pine

Name(S) lbf kgf N Notes
Major Species
Lodgepole Pine (Pinus contorta) 480 2,140
Ponderosa Pine (Pinus ponderosa) 460 2,050
Minor Species
Jeffrey Pine (Pinus jeffreyi) 500 2,220 Anatomically indistinguishable from, and also sold as, Ponderosa Pine.
Miscellaneous
Jack Pine (Pinus banksiana) 570 2,540