Environmental calculators
Carbon, solar payback, home energy, and household water. Every tool shows its formula, updates live, and works on any device.
Saved & recent
- Carbon Footprint CalculatorEstimate a household carbon footprint from electricity, natural gas, driving, and flying, then compare your annual tons of CO2e with the 16-ton US average.→
- Home Energy Audit CalculatorAudit any appliance in seconds: watts times hours per day gives annual kWh, annual cost, and how big a slice of an average US home’s 10,500 kWh it eats.→
- Solar Panel Savings CalculatorProject solar savings from system size, sun hours, derate, and your utility rate — year-one savings, 25-year totals, net cost after the federal credit, and payback.→
- Water Usage CalculatorTally shower, toilet, faucet, and laundry habits to see gallons per person per day, gallons per year, and how you stack up against the 80-gallon US average.→
How this manual is organized
Each entry above opens a one-page tool: inputs on the left, the live result on its color board, and beneath the card the formula with worked examples and the method's limits. Save the tools you use often — they'll wait on this shelf next visit.