Energy decisions, real payback math.

• #1 Most-searched

  Carbon Footprint True Cost Calculator

  Drop your flight tier, annual miles driven, diet, home size, electricity source, electronics replacement, shopping intensity, and preferred offset price. Calculator aggregates emissions across 7 buckets to compute annual CO₂e tonnage, compares to US median 16 t, costs the offset, and ranks the top 3 reduction levers by absolute t saved (with cost-to-implement framing — most are $0/t or save money). Anchored to EPA GHG Inventory, Project Drawdown research, Poore-Nemecek 2018 Science (diet emissions), and ICAO emissions database (flight cabin-class multipliers).

  780K+/month

• #2

  Flight Emissions + Offset Calculator

  Drop your route distance, route label, cabin class (economy / premium economy / business / first), round-trips per year, and offset price tier. Calculator computes annual CO₂e from your flights using ICAO basic-CO₂ methodology, surfaces a separate radiative-forcing-inclusive (Lee et al. 2021) sensitivity row, compares to the economy-class alternative (showing cabin penalty), and costs the offset at your chosen quality tier. Anchored to ICAO 2024 emissions methodology, Lee et al. 2021 atmospheric science, and Atmosfair / Verra / Gold Standard offset pricing.

  620K+/month

• #3

  Solar ROI Calculator

  Drop your monthly bill, local kWh tariff, roof area, panel tier, battery option, financing, net-metering policy, electricity-price appreciation, panel degradation, and time horizon. Calculator sizes the system to your usage (or roof, whichever is smaller), applies the IRS Section 25D 30% federal tax credit, simulates production with degradation and tariff escalation, and returns payback period, 20-yr savings, IRR, battery payback delta, and lifetime CO₂ avoided. Anchored to NREL PVWatts insolation, LBNL field-study degradation curves, and EIA grid-emissions data.

  450K+/month

Frequently Asked Questions

The most common questions we get about this calculator — each answer is kept under 60 words so you can scan.

• Why a separate Climate & Energy category instead of folding into Auto or Finance?

  Because the math is genuinely different. Energy decisions revolve around payback period, IRR, panel/equipment degradation curves, electricity-price escalation, net-metering policy, and emissions-per-dollar trade-offs that don’t map onto loan-EMI or commute-cost templates. Bundling solar into Auto would have hidden the differentiation — solar ROI depends on roof orientation and net-metering, not gas prices, and merits its own surface.
• Whose data and assumptions are baked in?

  Cost defaults: NREL Annual Technology Baseline (utility-scale + residential PV cost-per-watt), EIA residential electricity tariff data (state averages refreshed quarterly), Lazard Levelized Cost of Energy (LCOE) study for cross-tech comparisons, IRS Form 5695 for the residential clean energy credit (currently 30% federal). Performance defaults: NREL PVWatts insolation by region (1,200-1,500 kWh/yr/kW typical), industry-standard 0.5%/yr panel degradation (per LBNL field studies), 7%/yr AC heat-pump COP at moderate climate. Every default is a starting input, not a black box — every page links the source and lets you override.
• Are the calculators US-specific?

  Mostly yes for v1 — solar ITC at 30%, EIA tariff data, IRS Energy Star credits, US-style net-metering policy options. The underlying math (NPV / IRR / payback / degradation modeling) is universal; once US versions are stable we’ll layer UK / EU / India support with local subsidy programs (UK Smart Export Guarantee, EU MCS-certified installer pricing, India PM Surya Ghar). Outputs already let you override every assumption, so non-US users can run defensible numbers today by entering their local inputs.
• What does ‘net-metering policy’ mean and why does it dominate the result?

  Net metering is the rule that determines what your utility pays you for excess solar generation pushed back to the grid. Three regimes matter: (1) Full retail (1:1) — every excess kWh you export is credited at the same retail rate you’d pay to import; payback is fastest, generation valued at full tariff. (2) Partial / time-of-use export — excess credited at wholesale or avoided-cost rate (often 30-50% below retail); payback stretches by 2-4 yrs vs. full retail. (3) None / self-consumption-only — only the energy you use during generation counts (typically 30-40% of total without battery, 70-90% with); payback is longest, battery becomes economically necessary. Same hardware, same sun, three completely different paybacks — net metering policy is often the single biggest variable in the calc.

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