Are company cars Scope 1 or Scope 3?

Cars your business owns or leases are Scope 1. Employees' own cars used for business, often called grey fleet, are Scope 3 category 6, business travel. Hire cars for business trips are also category 6.

What is the emission factor for an average car in 2026?

For an average-sized car of unknown fuel, 0.26699 kg CO2e per mile in the DESNZ 2026 factors. An average diesel car is 0.27786 and an average petrol car 0.25993 kg per mile.

Should I use litres or miles for company cars?

Litres, whenever you have them from fuel cards or receipts. They reflect how the car was actually driven. The 2026 factors are 2.58354 kg CO2e per litre of diesel and 2.075 per litre of petrol. Use miles only for cars without fuel records, and never both for the same car.

How do I count an electric company car?

It has no exhaust emissions, so nothing in Scope 1. Charging you pay for away from your own sites is Scope 2. If it charges on a meter already in your electricity bills, those emissions are already counted, so don't add the miles as well.

Company car and grey fleet emissions: how to calculate them

Company cars your business owns or leases are Scope 1: use litres from fuel cards where you can (2.58354 kg CO2e per litre of diesel in 2026), or miles with the DESNZ car factor. Employees' own cars used for work, known as grey fleet, are Scope 3 business travel: take the miles from mileage claims and multiply by the car factor, 0.26699 kg CO2e per mile for an average car of unknown fuel in 2026.

Updated 6 October 2026 by the Carbon Recycling team. Figures use the official UK government conversion factors and are checked against the current gov.uk guidance.

First, sort your cars into two groups

The same journey in the same kind of car can land in different scopes, depending on who owns the car:

Car	Scope	Best data
Owned or leased by the business (company cars, pool cars)	Scope 1	Litres from fuel cards; miles if there are no fuel records
Owned by an employee and used for work (grey fleet)	Scope 3, category 6 business travel	Miles from mileage claims
Hire cars for business trips	Scope 3, category 6 business travel	Miles or litres from hire records
Employees driving to and from work	Scope 3, category 7 commuting	A staff survey

Getting this split right matters. Scope 1 is part of what SECR and a PPN 006 plan count as your direct emissions, and putting grey fleet there inflates them. Leaving grey fleet out altogether leaves a hole in category 6, one of the five Scope 3 categories PPN 006 asks for.

Company cars: litres first, miles second

If you have fuel cards or receipts, add up the litres and multiply by the fuel factor: 2.58354 kg CO2e per litre of diesel and 2.075 kg per litre of petrol in 2026. Those are the factors for forecourt fuel, which contains a share of biofuel. Litres pick up the real effect of driving style, traffic and load, which a per-mile average can't. See the diesel and petrol factor pages for earlier years.

If you only have mileage, use the per-mile factor for the car's size and fuel. Never record both litres and miles for the same car: that counts it twice.

The 2026 per-mile car factors

These are the DESNZ 2026 factors in kg CO2e per mile. They apply to company cars (Scope 1) and to grey fleet (Scope 3) alike: what changes is where you report the result, not the factor.

Size	Diesel	Petrol	Hybrid	Fuel unknown
Small car	0.23058	0.22943	0.18314	0.22986
Medium car	0.27696	0.2802	0.18794	0.27878
Large car	0.33643	0.42817	0.25499	0.36643
Average car	0.27786	0.25993	0.20857	0.26699

Hybrid means a self-charging hybrid. Plug-in hybrids and electric cars have their own factors.

If you know nothing about a car, the average car with unknown fuel is a reasonable default. Knowing the size and fuel is better, and it is easy to collect: add two questions to your mileage claim form. The average diesel car, average petrol car and average hybrid car pages show how each has changed since 2019.

Grey fleet: your mileage claims are the data

You already have a record of every business mile driven in staff's own cars, because people claim them. Export a year of mileage claims from your expenses or payroll system, total the miles, and multiply by the car factor. Leave out claims that are really commuting, which belongs in category 7.

Electric cars

An electric company car has no tailpipe, so nothing goes in Scope 1. Electricity you pay for to charge it away from your own sites is Scope 2: the 2026 factor for an average battery electric car is 0.04322 kg CO2e per mile. If it charges on a meter that is already in your electricity bills, don't add the miles, because the emissions are already in your Scope 2. An employee's own electric car on business is Scope 3 at 0.04749 kg per mile. See the electric car factor page.

A worked example

A small firm has three company cars and staff who claim mileage for client visits in their own cars.

Source	Data	Scope	Factor (kg CO2e)	tCO2e
Two diesel company cars, fuel cards	3,200 litres	1	2.58354	8.27
One hybrid company car, no fuel records	9,000 miles	1	0.20857	1.88
Staff mileage claims in their own cars	22,000 miles	3 (cat. 6)	0.26699	5.87

The company cars add 10.14 tonnes to Scope 1. The 22,000 miles of grey fleet add 5.87 tonnes to Scope 3 business travel: 37% of the firm's car emissions, from vehicles that never appear on a fuel card. Firms that pay mileage rather than provide cars can find grey fleet is one of their biggest sources, so it is worth getting the data right.

How Carbon Recycling helps

Carbon Recycling has separate entries for fuel for company vehicles, company cars by distance and employee cars, so each lands in the right scope automatically. For employee cars you choose business travel or commuting, and the car size and fuel if you know them. For other activities, see our five PPN 006 Scope 3 categories.