Enhanced Tool for Carbon Calculation


In the years since the buildcarbonneutral.org (BCN) calculator went live in 2007 it has served a vital purpose: in addition to educating people about the impact that construction’s embodied carbon can have on climate change, it is an easy-to-use tool for early assessment of that impact. The calculator is a valuable resource for smaller offices and practitioners who may not have time or budget to develop full life-cycle assessments (LCAs) but do want to educate their clients about the impacts of their projects. The free online tool also fills an important gap for project performance comparison within the industry, as demonstrated by its usage within AIA design awards programs, given its universal accessibility and ease of use.

At the same time, the limited level of detail within the tool means that design teams can’t make simple comparisons in materials that inform project decisions early in the process. This Mithun R+D project improves the existing calculator by allowing greater variability in the input data, expanding landscape impacts beyond soil sequestration and better communicating the results of the calculations and how they were generated.


The research team began by creating simple building models and performing LCA analyses on them. Repeated and incremental changes were made to those models and the results compared to establish the impacts of each of those changes. These LCAs used manufacturers’ carbon data and established LCA databases. This information will be incorporated into BCN as individual user inputs based on their projects. 

The above-ground biomass, soil sequestration and hardscape components have been generated through simplified LCA analysis of individual units of each of those assemblies. The users can input their estimated quantities by material to generate an LCA for their site.

Looking Forward

After an initial period of assessment and peer review, the BCN website will be updated with the broader set of input variables, an expanded landscape component, and results in kg/m2 to be consistent with worldwide standards for embodied carbon. A more explicit and transparent explanation of the methodologies and assumptions that went into the calculator will also be available online. As a collection, these improvements aim to enhance early design decision-making and embodied carbon reductions within the built environment for years to come.

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