Footwear Safety Codes: A Guide to Safety Boot Ratings

Safety boot labels are covered in codes, and at first glance they can look like alphabet soup. Once you know what they mean, though, they tell you exactly what a boot protects against and whether it suits your job. This guide explains the footwear safety codes and boot ratings used in the UK, from the headline S numbers to every extra letter, so you can read any label with confidence.

What are footwear safety codes?

Safety footwear sold in the UK is tested and certified to the EN ISO 20345:2022 standard. Every boot that meets it carries a 200 joule protective toe cap as a minimum, then adds features depending on its rating. The S codes are convenient bundles of features, while the individual letter codes describe specific tests a boot has passed. Reading both together tells you the full protection story, so you can be sure a boot is right for your workplace rather than guessing from the name alone.

The main safety boot ratings explained

The S ratings are the quickest way to compare boots. Here is what each one includes, with our matching ranges.

You can jump straight to the ranges for S1P,S3,S5 rubber safety wellingtons and S7 waterproof boots, or see the entry-level safety toe cap (SB) styles.

Additional protection codes

Beyond the S rating, extra letters flag specific protections. These are the ones you will see most often.

Many of these map to a dedicated range, including midsole penetration protection, metatarsal protection, heat resistant (HRO) and slip resistant (SR and SRC) boots.

How to read a safety boot label?

Put the codes together and a label reads like a sentence. A boot marked S3 SRC, for example, is a leather boot with a toe cap, antistatic properties, an energy absorbing heel, a water resistant upper, midsole penetration protection and a cleated outsole, that has also passed extra slip tests. Add HRO and you know the sole also resists heat contact, while an M mark tells you it protects the top of the foot. Once you can read the string of letters, you can match any boot to a job in seconds.

A quick word on slip resistance

Slip resistance changed with the 2022 standard. A base level of slip resistance is now required on all safety footwear, with an additional SR mark for boots that pass extra slip tests on demanding surfaces. You may still see the older SRA, SRB and SRC marks on boots certified to the previous standard, so it is worth checking which standard a boot was tested to, especially if you work on wet or greasy floors where grip is critical.

Do you legally need safety boots at work?

In the UK, where a risk assessment identifies a foot injury hazard, employers must provide suitable safety footwear free of charge under the Personal Protective Equipment at Work Regulations. The right rating depends on the risks in your workplace, which is exactly why these codes matter: they let you and your employer choose footwear that genuinely matches the job rather than relying on guesswork.

When do you need metatarsal or ankle protection?

Some jobs need protection beyond the standard toe cap. Metatarsal protection, marked M, shields the bones across the top of the foot from heavy falling objects, and is common in heavy industry, foundries and demolition. Ankle protection, marked AN, guards the ankle bone against knocks and is useful on uneven ground or where you handle awkward loads. If either risk applies to your work, look for these markings specifically rather than assuming a high S rating covers them, because it does not. Our metatarsal and ankle protection range gathers boots built for exactly these hazards.

Which codes matter most for common trades?

• Construction and groundwork: S3 for water resistance, penetration protection and grip, or S7 when you need full waterproofing on wet sites.
• Warehouse and indoor work: S1P for a lighter, breathable boot with toe and midsole protection where waterproofing is not the priority.
• Agriculture and washdown: S5 rubber wellingtons for fully waterproof, wipe clean protection in mud and slurry.
• Electronics and static-sensitive work: antistatic or ESD footwear, often with ametal-free build or a composite toe.
• Logistics and warehousing: S1P or S3 with a slip resistant sole for hard, sometimes wet floors.
• Roadworks and highways: S3 with hi-vis and, where hot surfacing is involved, an HRO heat resistant outsole.

Beyond the codes: fit and comfort still matter

The codes tell you what a boot protects against, but they say nothing about how it feels on your foot. A boot with the perfect rating is no use if it rubs or pinches, because an uncomfortable boot is one you will be tempted to leave off. Once you have shortlisted the right rating for your job, choose the pair that fits well, suits your working day and, ideally, that you can try for size. Protection and comfort together are what keep boots on feet and workers safe.

Frequently asked questions

What does S3 mean on a safety boot?

S3 means the boot has a 200 joule toe cap, antistatic properties, an energy absorbing heel, a fuel and oil resistant sole, a water resistant upper, midsole penetration protection and a cleated outsole. It is the most popular all round outdoor rating.

What is the difference between SB and S1?

SB is the basic level with just a 200 joule toe cap. S1 adds antistatic properties, an energy absorbing heel and a fuel and oil resistant sole, so it offers more everyday protection.

Is a higher S number always better?

No. The numbers describe different feature sets, not a simple ranking. An S1P is ideal indoors, while an S5 wellington suits wet, muddy work. The best rating is the one that matches your job.

What replaced WRU and SRC in 2022?

The water resistant upper marking WRU is now written as WPA. The old SRA, SRB and SRC slip marks were replaced by a baseline slip requirement plus an additional SR mark.