SECR carbon calculator — Scope 1, 2 & 3
A free, ungated calculator for your UK carbon footprint. Enter electricity and gas, other fuels, grey-fleet mileage and refrigerant top-up, and the tool returns instant tCO₂e with a full Scope 1, 2 and 3 breakdown using DEFRA's published conversion factors. Built for SECR preparers, ESOS lead assessors and in-house sustainability teams. Want a quick scope check first? Try the eligibility checker.
Electricity & gas
Scope 1 & 2Metered purchased energy. Electricity is Scope 2; natural gas combustion is Scope 1.
Factor: UK electricity — generation (location-based) — 0.17889 kg CO2e per kWh · DEFRA/DESNZ 2025. DEFRA sourceLocation-based UK grid average.
Other fuels
Scope 1Stationary and bulk fuels you burn on site or store. All Scope 1 (HVO well-to-tank is Scope 3).
Factor: LPG — 1.55713 kg CO2e per litre · DEFRA/DESNZ 2025. DEFRA source
Fleet & grey-fleet mileage
Scope 3Owned/leased fleet fuel sits under Other fuels (Scope 1). Use this section for grey-fleet — employee mileage in their own cars, where you only know distance (Scope 3).
Factor: Car — average petrol (per km) — 0.16453 kg CO2e per km · DEFRA/DESNZ 2025. DEFRA source
Refrigerants (F-gas)
Scope 1Fugitive emissions — refrigerant added during the period to top up leakage. All Scope 1.
Factor: Refrigerant R-410A — 2088 kg CO2e per kg · DEFRA/DESNZ 2025. DEFRA source
Total carbon footprint
0.00 tCO₂e
- Scope 1 — direct
- 0.00 tCO₂e
- Scope 2 — purchased energy
- 0.00 tCO₂e
- Scope 3 — indirect
- 0.00 tCO₂e
- Scope 1 + 2 (SECR core)
- 0.00 tCO₂e
SECR intensity ratio
SECR requires at least one intensity ratio, normally on Scope 1 + 2.
Enter a positive figure to see your ratio.
Calculated using the DEFRA/DESNZ 2025 UK Government GHG Conversion Factors for Company Reporting (tCO₂e = activity × factor ÷ 1000). Runs entirely in your browser — no activity data is sent to us. Verify factor values against the official DEFRA workbook before filing.
Download a tidy PDF summary
Your on-screen result is free to keep. Enter your email to unlock a one-click PDF and CSV export — and we'll have a specialist sanity-check your figures, free and no-obligation.
How the calculation works
For every line the tool applies the SECR formula: tCO₂e = activity × DEFRA factor ÷ 1000. Activity is your input — kWh of electricity or gas, litres of fuel, km of mileage, or kg of refrigerant added. Each line shows the exact factor, its value, the DEFRA/DESNZ version and a link to the source so your numbers are fully auditable. The tool sums the lines into a total and splits them across Scope 1 (direct), Scope 2 (purchased energy) and Scope 3 (indirect).
What's included
- Scope 1 — natural gas, LPG, gas oil/red diesel, fuel oil, kerosene, diesel, petrol, biomass and refrigerant (F-gas) leakage
- Scope 2 — purchased grid electricity (location-based)
- Scope 3— grey-fleet mileage in employees' own vehicles and the well-to-tank element of HVO biofuel
To keep the tool credible it does not cover process emissions (cement, lime, steel chemistry), clinical anaesthetic gases or the full breadth of Scope 3 (supply chain, business travel, commuting, waste, water). If those apply to you, a specialist can scope the full inventory.
Need the full report, not just the calculation?
Calculation is the easy part. A compliant SECR disclosure also needs a narrative section, an intensity-ratio choice, year-on-year context and methodology disclosure — all signed off by directors and filed at Companies House on deadline. We connect you with a vetted, IEMA-qualified SECR specialist who handles the whole thing. Speak to a specialist — free and no-obligation.