Grading Sawn Lumber

Wood is a natural material and by its very nature may contain different characteristics. The grading of American hardwood into categories helps determine the value and potential use for each board of sawn lumber. The rules for this grading process were established over 100 years ago by the National Hardwood Lumber Association (NHLA) and are still the standard for the U.S. hardwood industry and the basis for international trade.  


Our free guide combines detailed information on most American hardwood species, as well as a simplified explanation of the NHLA grading system in the second half of the guide.

species guide


The NHLA lumber grading rules adopted by the US hardwood industry are based on an imperial measurement system using inches and feet. In contrast most export markets are more familiar with a metric standard. Additionally, the grade rules were developed with random width and length lumber in mind. Any selection for particular specifications should be discussed prior to ordering.

The Grades

What follows outlines the standard NHLA grades: Clear Face Cuttings Grades (FAS, FAS One face, Selects, No.1 Common and No. 2A Common) and Sound Cuttings Grades (No. 2B Common). The NHLA states that these grades have “stood the test of time and of an exacting market, serving as a pattern for others”.

Characteristics and Defects

The following shows characteristics that occur in US hardwoods. Some are inherent to certain species and others are generic to all. These characteristics either occur naturally in the lumber or as a result of the drying process. As has already been discussed, the grades are based on the percentage of clear, defect free wood in the board.

Grading images

Select one of nine American hardwood species to see visual examples of each grade. This core selection of American hardwood species provides the perfect introduction to grading sawn lumber in accordance with the NHLA rules; the standard for the U.S. hardwood industry and for international trade.

Additional Guidance

Regional exceptions to the standard NHLA grades The NHLA grades cover the majority of commercial hardwood species growing in the USA. The following is a brief summary of the various species and colour sorting that can be ordered from the American supplier.