The Sustainability Score Calculator turns 15 everyday lifestyle questions into a single 0–100 score, an estimated annual CO₂e footprint, and a ranked list of the changes that would move your score the most. It's built for anyone curious about their environmental footprint who wants a quick, honest self-assessment rather than a multi-hour carbon audit. The sections below explain how the score is calculated, what each category measures, and where a 15-question quiz reaches the limits of what it can tell you.
How the score is calculated
Each of the 15 questions is answered on a 0–10 scale via the answer chips, where 0 represents the highest-impact habit (daily solo driving, meat every day, an old inefficient furnace) and 10 represents the lowest-impact option (car-free, vegetarian/vegan, a smart, well-insulated, renewably powered home). Questions are grouped into five categories, and each category's score is the average of its answered questions, scaled to a 0–100 range. The overall score is a weighted sum of the five category scores: Transportation counts for 30% of the total, Diet and Home Energy each count for 25%, Shopping counts for 15%, and Water counts for 5%. These weights roughly mirror how much each area typically contributes to a US household's carbon footprint, which is why the Transportation and Diet/Home categories dominate the result far more than any single Water-category answer.
What each category measures — and where the leverage is
Transportation (car use, transit, biking, flights) carries the most weight because personal vehicles and air travel are consistently among the largest sources of individual emissions — a single long-haul flight or year of daily solo commuting can outweigh dozens of smaller lifestyle choices. Diet (meat consumption, local/organic sourcing, food waste) and Home Energy (electricity source, insulation, thermostat habits, appliance efficiency) are tied for the next-largest share, reflecting how heavily animal agriculture and residential energy use factor into most footprints. Shopping (fast fashion, packaging, electronics replacement cycles) and Water (shower length) matter, but contribute far less to the overall score — which is intentional, since manufacturing and disposal impacts, while real, are typically smaller than transportation and energy use for most households. The improvement plan on the Results tab uses these weights directly: it ranks the three changes with the largest weighted point gain, so a Transportation fix usually outranks a similarly-sized Water fix.
Limits of a 15-question self-assessment
This calculator is a self-reported snapshot, not a scientific carbon audit. Answers are self-selected from a small set of chips, so it can't capture nuance like exact commute distance, specific vehicle fuel efficiency, regional electricity grid mix, or precise dietary breakdowns — a full lifecycle assessment would require far more detailed data. The CO₂e estimate is a linear approximation between a high-impact and low-impact reference lifestyle, useful for comparing scenarios against each other but not for reporting an exact personal footprint. The percentile comparison is calibrated to average US emissions patterns and isn't meaningful for comparing against other countries, many of which have very different baseline footprints. Treat the result as a directional guide for where to focus effort — Transportation and Diet/Home Energy first, given their weight — rather than a precise carbon accounting figure.