The world’s first building code can be traced back to around 1800 B.C., according to the Environmental and Energy Study Institute. Clearly, the idea of ensuring occupant and building safety through building codes has been around for a long time, but maintaining a working knowledge of codes and standards, and knowing design specifications for occupancies and loads, can be a tough challenge.

American Wood Council (AWC) aims to streamline the complexity of staying up-to-date with building codes by utilizing a variety of applications and calculators. These apps help builders and designers construct to the most up-to-date codes and standards in regard to wood construction. All AWC calculators are available for free and run on Windows 10 and on iOS and Android devices.

Span Calculator

Designing and building to account for certain loads and occupancies can be a time-consuming task, but the Maximum Span Calculator for Wood Joists and Rafters simplifies the process. It can perform calculations for all commercially available softwood and hardwood species and grades, as found in the National Design Standard (NDS) 2012 Supplement. The calculator also provides the option for multiple selections of species and grades for comparison. Common uniform loading conditions are available and adjustment factors for wet service conditions even allow calculation of deck joists.

Connection Calculator

The Connection Calculator provides users with an app-based approach to calculating capacities for single bolts, nails, lag screws and wood screws per the 2015 NDS for Wood Construction. This app offers a convenient way to determine both lateral and withdrawal connection values and includes adjustment factors for temperature, wet service, varying load durations, and end grain. The connection calculator also determines both lateral (single and double shear) and withdrawal capacities for wood-to-wood, wood-to-concrete, and wood-to-steel connections. For connections loaded in shear, the calculator presents results for each of the NDS-prescribed yield modes, and calls out the controlling result.

Heights & Areas Calculator

The Heights and Areas (H&A) Calculator is a joint effort between AWC, the International Code Council (ICC), and WoodWorks. It calculates the maximum heights and areas for buildings of various occupancies and fire protection. This helps designers and builders construct to code by quickly determining the allowable heights and areas based on the geometry of the site conditions (e.g., open frontage), type of construction, and occupancy. The app incorporates the 2006 through 2015 editions of the International Building Code (IBC), though it is neither meant to be a replacement for the IBC nor does it encompass all of the IBC’s design options.

Energy UA Calculator

Energy codes have become increasingly demanding, as have pressures to build with green materials. Wood naturally provides many advantages, such as its natural thermal resistance and low embodied energy. The Energy UA Calculator determines the opaque wall or fenestration U-factor based on the Total UA alternative compliance method allowed by ICC’s International Energy Conservation Code or International Residential Code. The U-factor indicates the heat-loss rate of a wall assembly—the lower the U-factor, the greater a wall’s resistance to heat flow and better ability to control heat loss. The Energy UA Calculator also gives insulation requirements needed for various wood wall assemblies in order to achieve the specified opaque wall U-factor in each climate zone. The calculator is consistent with AWC’s “Design for Code Acceptance 7, Meeting Residential Energy Requirements with Wood-Frame Construction.”

Building with the most up-to-date consensus-based building codes and standards is essential to ensuring building safety. Modern codes provide the industry with a baseline for estimating and managing risk when it comes to investing in long-term measures to achieve goals that can impact short-term profits. With the sheer volume of content that the consensus-based codes and standards incorporate, maintaining a working knowledge of the most recent versions can be extremely challenging. AWC aims to alleviate the challenge by developing applications like the ones mentioned above. While AWC’s calculators help design to these consensus-based codes and standards, it is still important to reference the codes and standards for final consultation.

AWC offers free live webinars and eCourses on these topics and more. For more applications, standards, and education on building with wood construction, visit

Bradford Douglas, P.E., is the vice president of engineering at American Wood Council (AWC). AWC is committed to ensuring a resilient, safe, and sustainable built environment. To achieve these objectives, AWC contributes to the development of sound public policies, codes, and regulations which allow for the appropriate and responsible manufacture and use of wood products.