Average plug-in hybrid car emission factor 2026 (UK, kg CO2e per mile)

The 2026 UK government emission factor for the average plug-in hybrid car is 0.15823 kg CO2e per mile, reported as Scope 1 and Scope 2. That is 4.9% lower than the 2025 factor of 0.16636. Including well-to-tank and grid losses, the full figure is 0.20683 kg CO2e per mile.

Updated 8 October 2026 by the Carbon Recycling team. Figures use the official UK government conversion factors and are checked against the current gov.uk guidance.

Work out your average plug-in hybrid car emissions

Miles in a year

= 1.90 tonnes CO2e in 2026 (Scope 1 and Scope 2)2.48 tonnes including well-to-tank and grid losses

Each mile × 0.15823 kg CO2e, the 2026 UK government (DESNZ) factor.

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Average plug-in hybrid car emission factor by year

Year	Scope 1 and Scope 2 (kg CO2e per mile)	Well-to-tank	Grid losses	Full figure	Change
2026	0.15823	0.047210	0.001390	0.20683	-4.9%
2025	0.16636	0.047210	0.001970	0.21554	-3.7%
2024	0.17270	0.047210	0.001950	0.22186	+17.1%
2023	0.14753	0.039270	0.003589	0.19039	+0.3%
2022	0.14706	0.042760	0.003380	0.19320	-3.6%
2021	0.15261	0.042760	0.003390	0.19876	-0.2%
2020	0.15284	0.036810	0.003460	0.19311	-15.1%
2019	0.17996	0.040810	0.005610	0.22638	–

Total kg CO2e for the seven greenhouse gases, from the official DESNZ files for each year. 2026 factor IDs: 4_301_3075_9_1, 8_301_3075_9_1. Where a factor jumps sharply between two years, it is usually because DESNZ changed its method or data source, not because the activity itself changed.

Worked example

Take one company car driven 12,000 business miles a year. 12,000 miles × 0.15823 kg CO2e = 1.90 tonnes CO2e, reported as Scope 1 and Scope 2. Adding well-to-tank and grid losses brings the full figure to 2.48 tonnes CO2e; the extra 0.58 tonnes are Scope 3 category 3.

How to report it

Plug-in hybrids run partly on petrol and partly on electricity from the grid. The government factor splits each mile into a petrol part, which is Scope 1 for a company car, and an electricity part, which is Scope 2 when you pay for the charging.

If the car charges on your own site's meter, that electricity is already in your bills, so count only the petrol part for those miles.

Where the data comes from

You'll usually find it in mileage logs, expenses claims or telematics, in miles. Keep the source documents: anyone checking your Carbon Reduction Plan or SECR report may ask how each figure was worked out.

Read more about how the factors change each year in our guide to the 2026 conversion factors, or see how we apply them in our methodology.

Related emission factors

Average hybrid car: 0.20857 kg CO2e per mile
Average battery electric car: 0.043220 kg CO2e per mile
UK grid electricity: 0.13096 kg CO2e per kWh
All UK emission factors

Frequently asked questions

Which year's factor should I use?

The set for the year your reporting period falls in. If your financial year spans two calendar years, use the set for the calendar year most of it falls in, and keep the same rule every year. Don't restate past years with new factors unless you are correcting an error.

Is this the DEFRA factor?

Yes. The UK government conversion factors used to be published by DEFRA, then BEIS, and since 2023 by the Department for Energy Security and Net Zero (DESNZ). Many people still call them the DEFRA factors.

Do I need to include well-to-tank emissions?

They are Scope 3 category 3 (fuel- and energy-related activities). SECR doesn't require them, and PPN 006 doesn't list category 3 among its required Scope 3 categories, but including them gives a more complete footprint and some customers ask for them.

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