Methodology
CommuteCarbon calculates emissions in line with the GHG Protocol Corporate Value Chain (Scope 3) Standard — Category 7: Employee Commuting. Working-from-home emissions are estimated using an incremental-allocation approach. All outputs are estimations and must be validated before use in external reporting.
Commuting
Annual emissions per transport mode = one-way distance × 2 × commuting days × emission factor. In company mode the result is scaled by employees × share %. Employees may use multiple modes per day, so mode-day totals can exceed office-attendance days.
Working from home
Electricity from work devices is computed as power (W) × hours/day × WFH days ÷ 1000 and multiplied by the country's grid emission factor. Heating uses incremental allocation combined with heating-day count — set heating days to 0 for tropical climates where AC (captured under devices) replaces heating.
Emission factors & reporting year
Factors are sourced (priority order) from country-specific national datasets (e.g. ADEME, EPA eGRID, UBA, ISPRA) with DEFRA/DESNZ applied as a fallback. The reporting year selector matches factors to that year; if the requested year is unavailable, the latest published DEFRA/DESNZ dataset is used and flagged in the audit trail.
Disclaimer
Results are estimates for informational purposes. For assurance-grade reporting, factors should be verified against the latest official publications for the reporting year.