Decarb’s carbon footprint methodology covers eight lifestyle categories using US and EU data sources. Every emission factor, assumption, and limitation is documented here. Results are expressed in tons CO₂e per person per year. This is an estimate — we are transparent about that throughout.
This methodology emphasises clarity over complexity — using accessible inputs and internally validated emission factors. Wherever possible, we prioritise consistency, avoid false precision, and align with Decarb’s mission to make carbon reduction measurable and continuous. Estimates are based on average emission factors applied to user-provided inputs; they are not audited or measured emissions.
Flight emissions are calculated using ICAO-based fixed factors per flight type. Decarb uses flight duration as the input proxy — simpler for users than route-distance entry. Values apply equally to US and EU users; flight emissions do not depend on departure country. For detailed single-flight calculations, the ICAO Carbon Emissions Calculator is recommended.
| Flight type | Reference route | Duration | Estimated emissions (tons CO₂e per roundtrip) |
|---|---|---|---|
| Short-haul | NYC → Chicago | 2h 33m | 0.296 |
| Medium-haul | NYC → Los Angeles | 5h 18m | 0.608 |
| Long-haul | NYC → Rome | 8h 08m | 0.775 |
Source: ICAO Carbon Emissions Calculator (ICEC). Values are per roundtrip flight. All values in tons CO₂e.
Only CO₂ is included in v3.1. Aviation’s non-CO₂ climate effects — contrails, NOx, induced cloudiness — can roughly double the climate impact of a flight (Radiative Forcing Index of approximately 1.9–2.7×). These effects are excluded in this version to maintain comparability with EPA and ICAO baselines. Inclusion of non-CO₂ effects is under consideration for v3.2 as an optional toggle.
Home energy emissions are calculated from housing type combined with heating system type and electricity usage. Scope covers operational emissions only (Scope 1 and 2). The calculation routes all heating types through a housing-type kWh baseline table — this eliminates the double-counting error present in versions prior to v2.3.
The US national average grid emission factor is 0.350 kg CO₂e/kWh, sourced from eGRID 2023 (full CO₂e, AR5 GWP basis). Users can enter their ZIP code to apply a subregional eGRID factor. Source: EPA Emissions Factors Hub 2025 / eGRID 2023.
EU users are assigned a country-level grid emission factor based on their country selection. Factors are drawn from the EEA annual GHG intensity of electricity generation dataset (EEA 2024). Country-specific values range from approximately 0.02 kg CO₂e/kWh (Norway) to 0.70 kg CO₂e/kWh (Poland).
Each heating type is modelled via a 2D kWh baseline table indexed by housing type and heating system. The heating type determines kWh consumption; no separate fixed emission value is added on top.
| Heating type | US method | EU method | Source |
|---|---|---|---|
| Natural gas | 5.3 kg CO₂/therm × therms/yr | 0.244 kg CO₂/kWh × kWh/yr | EPA GHG Hub 2025 |
| Fuel oil | 10.21 kg CO₂e/gallon × EIA RECS consumption by housing type | N/A (LP/propane used) | EPA GHG Hub 2025 / EIA RECS 2020 |
| Electric resistance | Via kWh baseline × 0.350 kg CO₂e/kWh | Via kWh baseline × country grid factor | EIA RECS 2020 / eGRID 2023 / EEA 2024 |
| Heat pump | Via kWh baseline, COP 2.8 (AHRI) | Via kWh baseline, COP 3.0 (EU ErP regs) | EIA RECS 2020 / AHRI / EU ErP |
| District heating (EU only) | Not modelled | Country-level factors (IEA World Energy Balances 2023 / national GHG inventories) | IEA WEB 2023 |
Scope: operational emissions only. Building embodied carbon and upstream fuel extraction are excluded. US baselines from EIA RECS 2020. EU baselines from ODYSSEE-MURE 2023 and JRC TABULA.
Solar panel systems reduce grid draw proportionally to system size (kW installed). Battery storage increases solar self-consumption, reducing grid draw further. Both are modelled as reductions to electricity purchased from the grid, not as separate emission sources.
Food emissions are estimated from dietary pattern using lifecycle emission factors. Scope covers farm to retail. The same four diet archetypes and factor values apply to both US and EU users — the primary driver is dietary composition, not geographic food system. According to Poore and Nemecek (2018), food production is responsible for approximately 26% of global greenhouse gas emissions, making dietary choices one of the highest-leverage individual actions.
| Diet type | Estimated emissions (tons CO₂e/yr) | Reference range | Primary source |
|---|---|---|---|
| Vegan | 0.4 | 0.3 – 0.5 | Poore & Nemecek (2018) |
| Vegetarian | 1.2 | 1.0 – 1.4 | Heller & Keoleian (2015) |
| Flexitarian (limited meat and dairy) | 1.7 | 1.5 – 2.0 | USDA / Poore & Nemecek |
| Omnivore (daily meat and dairy) | 2.3 | 2.0 – 2.5 | USDA / CoolClimate (UC Berkeley) |
No regional dietary variance applied. Results are indicative averages. Cooking energy emissions are captured in the home energy category.
Net waste footprint equals emissions from landfilled waste minus avoided emissions from recycling and composting. US values are based on the EPA WARM model (v15) with average waste generation of approximately 0.8 tons per person per year. EU values are lower, reflecting higher recycling rates and wider adoption of waste-to-energy infrastructure. EU factors are derived from Eurostat municipal solid waste data (env_wasmun 2023).
| Waste behaviour | US (tons CO₂e/yr) | EU (tons CO₂e/yr) | Source |
|---|---|---|---|
| No recycling | 0.42 | 0.14 | EPA WARM v15 / Eurostat env_wasmun 2023 |
| Recycling | 0.27 | 0.07 | EPA WARM v15 / Eurostat env_wasmun 2023 |
| Minimalist (reduce, reuse, recycle) | 0.15 | 0.03 | EPA WARM v15 / Eurostat env_wasmun 2023 |
EU default tier pre-selected based on country-level recycling rates from Eurostat 2023. Countries above 25% recycling rate default to the recycling tier.
Emissions are estimated from monthly spending bracket multiplied by an emission-weighted basket of categories using Exiobase 3.8.2 environmentally extended input-output factors. US values are calibrated to the US Consumer Expenditure Survey and inflation-corrected for US CPI 2019–2025 (approximately +25%). EU values use the Exiobase 3.8.2 EU average household consumption basket at purchaser prices, with EU HICP inflation 2019–2025 (+22%, Eurostat) applied. EU values are 54–79% of equivalent US values, reflecting lower EU manufacturing carbon intensity and stronger eco-design regulation.
| Monthly spending bracket | US (tons CO₂e/yr) | EU (tons CO₂e/yr) | Source |
|---|---|---|---|
| Less than $150 / €150 | 0.50 | 0.27 | Exiobase 3.8.2 / USEEIO v2 |
| $150 – $300 / €150 – €300 | 1.10 | 0.81 | Exiobase 3.8.2 |
| $300 – $500 / €300 – €500 | 1.95 | 1.44 | Exiobase 3.8.2 |
| More than $500 / €500 | 2.75 | 2.16 | Exiobase 3.8.2 |
Electronics counted once at point of purchase to avoid overestimation. Services (health, education, etc.) are included in the basket at lower emission intensity.
Finance emissions reflect how personal savings and investments are deployed by banks and funds — known as financed emissions or Scope 3 Category 15 under the GHG Protocol. These are indirect emissions attributed to the capital provider. Emission factors are from PCAF (Alexander et al. 2023) and GreenFi/Project Drawdown. Default balances are set to median values by locale: $8,000 bank and $87,000 investments for US users (Federal Reserve Survey of Consumer Finances 2022), and €5,000 bank and €20,000 investments for EU users (ECB Household Finance and Consumption Survey 2021). Users can adjust both balances via sliders.
| Financial behaviour | Estimated emissions (tons CO₂e/yr) | Basis |
|---|---|---|
| Standard banking and investment | 4.8 | $8k × 0.24 kg/$·yr + $87k × 0.033 kg/$·yr |
| Green bank + green investment fund | 1.9 | $8k × 0.057 kg/$·yr + $87k × 0.017 kg/$·yr |
| No bank account / no investments | 0.0 | No financed emissions modelled |
| Financial behaviour | Estimated emissions (tons CO₂e/yr) | Basis |
|---|---|---|
| Standard banking and investment | 1.9 | €5k × 0.24 kg/€·yr + €20k × 0.033 kg/€·yr |
| Green bank + green investment fund | 0.6 | €5k × 0.045 kg/€·yr + €20k × 0.017 kg/€·yr |
| No bank account / no investments | 0.0 | No financed emissions modelled |
Sources: PCAF Standard, GHG Protocol Scope 3 Category 15, Alexander et al. (2023), GreenFi / GABV, Project Drawdown, Federal Reserve SCF 2022, ECB HFCS 2021.
The banking emission factor for EU users (0.24 kg CO₂e/€-yr) is derived from US bank lending data. EU banks operate under EU Taxonomy, CSRD, and EBA ESG requirements that structurally constrain fossil fuel lending. This factor likely overstates EU banking emissions. No better publicly available factor exists at the time of publication. A revised EU-specific banking factor will be reviewed in v3.2 as CSRD disclosure data becomes available (2026–2027).
Finance emissions are not due to personal spending behaviour but to how banks and funds allocate capital. This category frequently produces the largest single contribution to an individual footprint at default balance levels. Switching to green banking and investment alternatives can produce large modelled reductions — this reflects the underlying emission factor data, not an exaggerated claim. Actual portfolio emissions depend on holdings, allocation, and the data methodology used by each institution.
Emissions are assigned only for explicitly carbon-intensive leisure activities not already captured in other categories. Social and leisure activities covered under food or goods are not double-counted here.
| Lifestyle description | Estimated emissions (tons CO₂e/yr) | Notes |
|---|---|---|
| Outdoor physical activities only (hiking, running, yoga) | 0 | No direct emissions |
| Occasional bars, restaurants, cinema | 0 | Captured under food and goods — not double-counted |
| Frequent bars, restaurants, cinema | 0 | Same as above |
| Carbon-intensive hobbies (motorboating, motorsports) | 0.6 | Estimated from approximately 50 hours/year of high-emission leisure activity |
Sources: US EPA Emissions Factors Hub; Decarb internal estimate. Only direct fuel-burning leisure activities are assigned emissions.
Ground transport emissions are calculated from vehicle type multiplied by an emission factor, scaled linearly to actual annual mileage against a baseline. All ICE vehicle factors use full CO₂e (CO₂ + CH₄ + N₂O) from EPA GHG Hub 2025 — a correction from earlier versions that used CO₂-only factors. US baseline is 12,000 miles/year (FHWA); EU baseline is 12,500 km/year (Eurostat). Scope covers operational vehicle emissions only (Scope 1 for ICE, Scope 2 for EV). Vehicle manufacturing and embodied carbon are excluded for consistency.
| Transport mode | Estimated emissions (tons CO₂e/yr) | Basis |
|---|---|---|
| No personal vehicle / public transit | 0.45 | Bus, train, and occasional rideshare (EPA GHG Hub 2025) |
| Hybrid or efficient car | 2.4 | 12,000 mi/yr at 45 MPG, full CO₂e |
| Standard petrol car | 4.3 | 12,000 mi/yr at 25 MPG, full CO₂e |
| Large SUV or truck | 6.3 | 12,000 mi/yr at 17 MPG, full CO₂e |
| Electric vehicle | 1.5 | 12,000 mi × 0.34 kWh/mi × 0.350 kg CO₂e/kWh (eGRID 2023) |
EU transport factors are calculated per kilometre using EEA new car CO₂ fleet averages (EEA 2022). EU electric vehicle emissions use the user’s country-level grid factor. Annual distance default is 12,500 km (Eurostat). Mileage scaling applies in the same way as US: vehicle type × emission factor × (actual km ÷ 12,500 km baseline).
Sources: US EPA Emissions Factors Hub 2025 (full CO₂e), FHWA, eGRID 2023, EEA new car CO₂ 2022. Tailpipe emissions only for ICE; EV uses grid emission factor at point of charging.
Decarb’s paid subscription includes the physical removal of 2 tons of carbon dioxide equivalent (CO₂e) per subscriber per year. This figure represents Decarb’s considered position on a meaningful individual-scale CDR contribution — grounded in the consumption gap between current average footprints and 1.5°C-aligned budgets, and in the IPCC’s finding that CDR is required across all pathways to limit warming to 1.5°C. The removal component is a complement to the personalised reduction plan, not a substitute for reducing estimated emissions.
Carbon offsets represent avoided emissions: a coal plant not built, a forest not cut, an activity prevented. Carbon dioxide removal (CDR) is categorically different — it refers to CO₂ already present in the atmosphere being physically extracted and stored. According to the IPCC AR6 Working Group III (2022), CDR is required at scale in addition to deep emissions cuts across all 1.5°C-aligned pathways; it is not an alternative to reducing emissions. Decarb sources only carbon dioxide removal credits. Avoided-emission offsets, legacy Clean Development Mechanism (CDM) credits, and credits without independent measurement, reporting, and verification (MRV) are excluded from the portfolio.
The IPCC Sixth Assessment Report (2022) identifies carbon dioxide removal as a necessary component of every modelled 1.5°C pathway — required alongside rapid, deep emissions reductions. The report does not prescribe a single per-capita CDR figure; it describes aggregate global CDR requirements across a range of scenarios. Decarb does not present the 2t figure as a direct IPCC prescription.
Instead, the 2t figure is grounded in two complementary bodies of research. First, the consumption gap: C40 Cities and Oxfam research on 1.5°C-aligned individual consumption budgets estimates a sustainable consumption footprint of approximately 2.5 tons CO₂e per person per year by 2030. The average US household currently produces an estimated 14.5 tons CO₂e per year — a gap of approximately 12 tons relative to a 1.5°C-aligned budget. The reduction plan is designed to close this gap through behavioural and investment changes; the 2t annual removal addresses a meaningful portion of the residual gap while the plan is being worked through. Second, the Oxford Principles for Net Zero Aligned Carbon Offsetting (University of Oxford, 2020; updated 2024) provide a framework for individual and organisational CDR use. The Oxford Principles recommend prioritising CDR over avoided-emission offsets, sourcing high-permanence removal where possible, and treating removal as a complement to — not a substitute for — emission reductions. Decarb’s portfolio and framing are designed to be consistent with all four Oxford Principles.
Estimated average US household footprint: 14.5 tons CO₂e/yr. 1.5°C-aligned individual consumption budget: ~2.5 tons CO₂e/yr (C40 Cities / Oxfam consumption research; EPA national GHG estimates). The reduction plan closes the gap through action; the 2t removal addresses a portion of the residual while the plan is implemented.
Each subscription delivers 2 tons CO₂e removed per year. The current live tier (T1 — Nature) sources nature-based credits via the Gold Standard Marketplace. Higher-permanence tiers are in development and will be added as supplier relationships and volumes are confirmed.
| Tier | Project types | Registry | Permanence | Status |
|---|---|---|---|---|
| T1 — Nature $9/month · $49/year | Mangrove restoration, improved forest management (IFM), soil carbon — satellite MRV required | Gold Standard Marketplace | Medium (100–500 yrs) | Live |
| T2 — Blended | Nature-based (70%) + agricultural biochar (30%) | Gold Standard + Puro.earth (EBC) | Medium–high (100 yrs to 1,000+ yrs) | Coming soon |
| T3 — Permanent | Premium biochar (60%) + enhanced rock weathering (40%) | Puro.earth (EBC) + Isometric | Very high (1,000+ yrs; geological) | Coming soon |
The Gold Standard for the Global Goals is an independent certification body founded in 2003, backed by over 80 NGOs including WWF. Gold Standard-certified projects must demonstrate additionality (the removal would not have occurred without the credit revenue), permanence, and independently verified community co-benefits. Credits are sourced directly through the Gold Standard Marketplace (marketplace.goldstandard.org). Retirement is executed on the Gold Standard registry in the subscriber’s name. Each retirement generates a unique, permanently published retirement ID that is not transferable or re-usable. Retirement confirmation and project details are sent to the subscriber by email within 30 days of purchase.
Avoided-emission offsets of any kind. Legacy CDM credits. Credits without independent third-party MRV. Soil carbon credits relying on modelled (non-sampled) baselines. Any project not registered under Gold Standard, Puro.earth, or Isometric. ACR (American Carbon Registry) forestry credits pending methodology reforms.
Decarb purchases removal credits monthly in bulk, based on the number of active paid subscribers at the time of purchase. The purchase volume is calculated as: active paid subscribers × 2 tons ÷ 12. Credits are retired in the subscriber’s name within 30 days of each monthly purchase. Retirement records — including project name, registry, retirement ID, and volume — are available on request at [email protected]. Credits are not resold, re-used, or allocated from buffer pool reserves. Each retirement corresponds to a unique credit on the Gold Standard registry and is permanently cancelled on retirement. An annual independent audit of all retirements against subscriber counts will be published on this page.
Nature-based reversal risk (T1). Nature-based removals carry inherent reversal risk from fire, drought, disease, and land-use change. Gold Standard’s buffer pool mechanism requires projects to hold a percentage of credits in reserve against future reversals. Decarb requires satellite MRV as a minimum for any IFM credits selected; projects relying solely on modelled baselines are not eligible. No nature-based credit methodology fully eliminates reversal risk; this is an accepted and documented limitation of the Tier 1 portfolio.
IFM over-crediting risk. A 2023 study published in Science (West et al.) found evidence of systematic over-crediting in a sample of REDD+ improved forest management projects. Decarb mitigates this by applying satellite-verified MRV as a sourcing requirement and by diversifying across project types — mangrove restoration and soil carbon credits carry lower over-crediting risk than IFM. The portfolio is reviewed annually against any updates to Gold Standard’s IFM methodology.
Removal does not constitute carbon neutrality. Purchasing a Decarb removal subscription does not make a subscriber carbon neutral or net zero. The removal of 2 tons CO₂e addresses a portion of the consumption gap; the remaining gap must be addressed through the reduction actions in the personalised plan. Decarb does not claim or imply carbon neutrality in any product, communication, or marketing material.
Sources: IPCC AR6 WGIII (2022); C40 Cities / Arup / University of Leeds (2019); Oxfam International (2021); University of Oxford Net Zero Principles (2020, updated 2024); West et al. (2023) Science; Gold Standard for the Global Goals v1.2 (2022); Gold Standard Marketplace.
If you identify an error in our methodology or emission factors, contact us at [email protected]. Verified errors are investigated and corrected promptly. The internal methodology specification is versioned and updated with every change to emission factor values or calculation architecture.