Environmental Impact Calculator Formula

Understand the math behind the environmental impact calculator. Each variable explained with a worked example.

Use the Environmental Impact Calculator

Formulas Used

Environmental Impact Score

overall_score = (carbon_score * 0.4 + water_score * 0.2 + waste_score * 0.2 + land_score * 0.2)

Carbon Score

carbon_out = carbon_score

Water Score

water_out = water_score

Waste Score

waste_out = waste_score

Variables

VariableDescriptionDefault
co2_tonsAnnual CO2 Emissions(metric tons)12
water_gal_dayDaily Water Usage(gallons)100
waste_lbs_weekWeekly Waste to Landfill(lbs)25
land_sqftLand Footprint(sq ft)5000
carbon_scoreDerived value= 100 - co2_tons / 16 * 50calculated
water_scoreDerived value= 100 - water_gal_day / 100 * 30calculated
waste_scoreDerived value= 100 - waste_lbs_week / 30 * 30calculated
land_scoreDerived value= 100 - land_sqft / 10000 * 20calculated

How It Works

How to Calculate Environmental Impact Score

An environmental impact score combines multiple factors into a single metric.

Formula

Score = Carbon(40%) + Water(20%) + Waste(20%) + Land(20%)

Each component is scored 0-100 based on comparison to benchmarks:

  • Carbon: US average 16 tons/year
  • Water: 100 gal/day average
  • Waste: 30 lbs/week to landfill
  • Land: normalized to 10,000 sq ft

    • Higher scores indicate lower environmental impact.

    Worked Example

    A person with 12 tons CO2, 100 gal/day water, 25 lbs/week waste, 5,000 sq ft.

    co2_tons = 12water_gal_day = 100waste_lbs_week = 25land_sqft = 5000
    1. 01Carbon: 100 - 12/16*50 = 62.5
    2. 02Water: 100 - 100/100*30 = 70
    3. 03Waste: 100 - 25/30*30 = 75
    4. 04Land: 100 - 5000/10000*20 = 90
    5. 05Overall: 62.5*0.4 + 70*0.2 + 75*0.2 + 90*0.2 = 72.0

    Frequently Asked Questions

    What does the environmental impact score mean?

    The score rates your environmental impact on a 0-100 scale where higher is better. 80+ is excellent, 60-80 is good, 40-60 is average, and below 40 needs significant improvement.

    Why is carbon weighted more heavily?

    Climate change is the most urgent environmental challenge. Carbon emissions from energy and transport have the largest single impact on global environmental health.

    How can I improve my score?

    Focus on the lowest-scoring category first. Reducing carbon (renewable energy, less driving) typically has the biggest impact. Then address water conservation and waste reduction.

    Ready to run the numbers?

    Open Environmental Impact Calculator