The American Wood Council’s (AWC) popular online span calculator was recently updated to allow user input of machine stress rated (MSR) lumber and machine evaluated lumber (MEL). With manufacturers taking a renewed interest in machine grading technology and attempting to derive greater value from the premium products they manufacture, having MSR and MEL in the span calculator permits them to point users to this tool for their lumber joist sizing needs. Grades and species shown represent those most commonly manufactured and available today.

Incorporation of MSR and MEL will add even more flexibility to the most popular tool on the AWC website. With an average of 50,300 monthly total page views, the span calculator generates more than one third of the traffic to the AWC website.

Tom Rogers of iLevel noted, "The addition of MSR/MEL grades in AWC’s online Span Calculator expands lumber specification options for architects and engineers when designing for joists and rafters. It creates visibility that MSR/MEL products are not just for manufacturing pre-fabricated truss components, but that the performance characteristics valued in trusses can be extended to joists and rafters as well."

The span calculator is a free tool available on the AWC website at For more information, contact Buddy Showalter at