Tyre date code UK: how to read the DOT and E-mark

Read a tyre's age from the 4-digit date code (week, year), decode the E-mark, and know the UK age rules and what part-worns you must refuse.

Week first, then year

A tyre's age is in the last four digits of the DOT code on the sidewall. The first two digits are the week of manufacture and the last two are the year, so 1923 is week 19 of 2023.

That's it. The rest of the DOT string is the factory and the maker's own codes, and you don't need either to price or grade a tyre. Read the four digits, then work out the age against today's date.

Don't read 2621 as a month and a day. Week 26 of 2021, nothing else.

Why it says DOT on a British tyre

DOT is the US Department of Transportation's marking. Many tyres are built for more than one market, so the US tyre identification number turns up on plenty of tyres sold here too. Under the US rule, 49 CFR 574.5, a new tyre's number has three parts.

Two-symbol plant codes were allowed until 13 April 2025, so both lengths are genuine. A retreaded tyre carries a shorter number with an "R" marked separately.

UN ECE Regulation 30, the European tyre standard the UK uses, asks for the same thing in its own words: a group of four digits, week first, then year. It also allows the date to be on one sidewall only. Turn the tyre over before you write it off as unmarked. On a fitted wheel, look at the inner face with a torch.

Three-digit codes: anything made before 2000

Before 1 January 2000, Regulation 30 let makers show the date with three digits: two for the week and one for the year. A code like 457 meant week 45 of a year ending in 7. 1997, or 1987. You can't tell which. It doesn't matter any more. Every tyre with a three-digit date is now well over 25 years old, and it comes off the rack and goes in the scrap pile. Classic car owners sometimes bring these in and ask for them to be refitted. Say no, and say why.

The E-mark, and what E11 means

Next to the size you'll find a circle with a capital E and a number, followed by a long approval number. That's the UN ECE type-approval mark, and it's the one that matters for UK law.

Reading an E-mark:

• The number after the E is the country whose authority approved the tyre. 11 is the United Kingdom.
• The first two digits of the approval number show the series of amendments the tyre was approved to. In the Regulation 30 text it's 02.
• The rest is the approval number itself.

Regulation 30's own example is a circled E 4 with approval number 022439, meaning approved in the Netherlands to the 02 series. The number tells you which country's authority approved the tyre. It doesn't tell you where the factory is.

You may hear people talk about UKCA marking on tyres since Brexit. We couldn't find a GOV.UK source that says car tyres need a UKCA mark, and the UK rules we checked still point to the UN ECE tyre regulations. The E-mark is what to look for. For part-worns it's a legal requirement, as below.

How old is too old?

For cars, there is no legal age limit in the UK. Goodyear's MOT tyre guide says there is currently no guidance on tyre age for passing the MOT on private passenger vehicles.

Heavy vehicles are different. From 1 February 2021, the Construction and Use Regulations stopped tyres over 10 years old being used on the front steered axles of HGVs, buses and coaches, and on all single wheels of a minibus with 9 to 16 passenger seats. DVSA's explanation on the GOV.UK Moving On blog adds three practical points:

• age is worked out from the date code, so the code must be legible on those vehicles;
• a retread counts from the date it was retreaded, not from the original casing;
• an illegible date code on a front steered axle fails the annual test.

For everything else, go by the maker. Michelin recommends a thorough inspection every year once a tyre is five years old and replacement ten years after manufacture, whatever the tread looks like, and that includes the spare. Rubber ages on a shelf as well as on a car. Look for fine cracking in the sidewall and between the tread blocks.

What to refuse on a part-worn

The Motor Vehicle Tyres (Safety) Regulations 1994 don't set an age limit for part-worns. They do set a list of things that make a tyre illegal to supply, and the date code check is the moment to run through it. Refuse the tyre if:

1. a non-retreaded car or van tyre has no E approval mark (or the small-e mark from the old EC tyre directive);
2. the load index and speed symbol aren't moulded into the sidewall;
3. it isn't marked PART-WORN in capitals at least 4 mm high next to each approval mark (you can add this yourself; the government-backed Business Companion guide mentions cold-vulcanised rubber labels, and the regulations rule out hot branding or cutting);
4. the tread is under 2 mm anywhere across the full breadth;
5. there's exposed ply or cord, a bulge, or a cut over 25 mm or 10% of the section width reaching the cords;
6. it has a repair that wasn't done properly to the British Standard;
7. the date code is three digits.

Points 1 to 6 are the law. Point 7 is common sense. Many careful part-worn sellers add their own age cut-off on top and put the date code on the invoice.

Write the code in chalk on the tread and in your stock record before the tyre goes on the rack. Ten seconds, and nobody has to hunt for it later with a torch. Then gauge the tread against our tread depth chart and check the size and load rating with the load index and speed rating chart.

DuroBay is a free app for tyre shops that keeps your stock list and reads the size, brand and date code from a photo of the sidewall.