THE NUMORIX GUIDE
How to use the Carbon Footprint Calculator
Last reviewed September 14, 2026
What this calculator does
The engine computes four component values and adds them: car miles x 0.
Formula and method
The engine computes four component values and adds them: car miles x 0.404, flights x 0.255, electricity kWh x 0.417 plus natural-gas therms x 5.3, and meat meals x 0.007. Each component and the total are rounded to two decimals and labeled tons of CO2 per year.
Variables and inputs
Enter annual car miles, flights, household electricity in kWh per year, natural gas in therms per year, and meat meals per year. The inputs are not converted or normalized beyond the fixed multipliers, and the engine returns transportation, flight, home-energy, diet, and total values.
Worked example
For 1,000 car miles, 1 flight, 500 kWh, 10 therms, and 50 meat meals, car emissions are 1,000 x 0.404 = 404.00; flight emissions are 0.255; home emissions are 500 x 0.417 + 10 x 5.3 = 261.50; diet emissions are 50 x 0.007 = 0.35. The displayed total is 666.11 tons CO2/year after rounding.
How to interpret the result
The result is the sum of the engine's category scores, so changing one input changes only its component and the total. It does not estimate a complete personal footprint from every source of greenhouse-gas emissions.
Common mistakes to avoid
Enter annual quantities rather than monthly quantities, and do not enter electricity dollars where kWh are required. Count flights as the engine expects rather than trying to add route miles, and keep natural gas in therms rather than cubic feet.
Assumptions and limitations
The coefficients are hardcoded and the output label says tons even though the resulting scale is not a plausible household-footprint scale for ordinary inputs. The engine does not document flight distance, vehicle type, grid mix, gas composition, diet mix, lifecycle boundaries, offsets, or non-listed emissions. Treat this as an implementation-specific score and verify units before using it for reporting or claims.