DIN EN 1335 explains: Why this standard saves your back

Let's be honest: When you think of " office chairs ," you probably first think of design, color, or price. Understandable. But if you or your employees are sitting on them for eight hours a day, there's one combination of letters that's more important than anything else: DIN EN 1335 .

Perhaps you've already come across the term somewhere in the fine print. Perhaps a salesperson mentioned it during a consultation. But the crucial question is:

Why is it practically impossible to avoid this standard and a GS-certified chair in Germany – especially in a professional setting?

In this article, we'll look at it without technical jargon: what's behind the standard, why it's your best insurance against back pain , how it saves you money in the long run – and what you really need to pay attention to when buying it.

Why we need to talk about standards (instead of just "convenient")

The reality in German offices is sobering: We sit for too long, and we often sit incorrectly. Back pain, tense shoulders, numb legs – this is rarely "bad luck", but mostly the result of poor equipment.

This is precisely where DIN EN 1335 comes into play. It is not an academic luxury, but a set of objective minimum requirements to ensure that a chair not only feels "cozy" in the first five minutes, but keeps you reasonably healthy for years to come.

In addition, there is the legal framework:

In Germany, workplace ergonomics is not purely a private matter. The Occupational Health and Safety Act, the Workplace Ordinance, and the regulations of the employers' liability insurance associations, simply put, require safe and ergonomic equipment. An employer who in 2025 still indiscriminately buys cheap chairs without any discernible standard is acting shortsightedly – ​​both in terms of health and finances.

Because every herniated disc , every chronic back injury, and ultimately every "bargain chair" that needs to be replaced prematurely, indirectly ends up exactly where it hurts the most: in the wallet.

What exactly is DIN EN 1335?

In short: DIN EN 1335 is the European standard for office chairs. It regulates three things:

• Dimensions: How high, how deep, how wide should a chair be to fit adults in the office?
• Safety: Does the chair wobble? Can fingers get pinched? Is the base stable enough?
• Durability: Can the chair withstand the daily use of an eight-hour workday for years?

A chair that meets this standard is not a decorative object, but a tool. And that is an important distinction.

Type A and Type B – and why I prefer A

Not all standard chairs are the same. DIN EN 1335 distinguishes between different types, of which two are particularly relevant in practice:

• Type A – the all-rounder: Largest adjustment range for seat height, seat depth, and backrest. It fits both short and tall people. In my opinion, this is the only sensible choice for offices with mixed teams.
• Type B – the solid standard: Slightly less leeway, but perfectly fine for the “average user” as long as the workforce is not too physically diverse.

I'm deliberately leaving Type C out: it rarely plays a meaningful role in typical German offices. If investments are to be made, then please ensure that as many employees as possible truly benefit.

DIN EN 1335 and the GS mark – the duo you should look out for

In Germany, you will very often see the combination of DIN EN 1335 and the GS mark ("Tested Safety") on higher-quality office chairs. The GS mark means that an independent testing body – such as TÜV or another accredited institution – has tested the chair for safety according to defined criteria.

💡 Pro tip:
If you're not a fan of standards, the combination of "tested according to DIN EN 1335" in the data sheet and a GS mark on the chair is one of the strongest quality indicators you, as a layperson, can recognize at a glance. Those who demonstrably meet these criteria are in a different league than anonymous imported goods without any documentation.

What a chair according to DIN EN 1335 must be able to do in practice

Let's forget about the standard numbers for a moment. What matters is what you feel in your back, legs, and neck. The most important points:

1. Seat height and seat depth

A good chair needs reserves. Whether you are 1.60 m or 1.85 m tall: your feet must be flat on the floor, and your knees and hips should form approximately a 90-degree angle.

Equally important is the seat depth – that is, the distance between the backrest and the front edge of the seat. Ideally, it should be:

• The thighs are well supported.
• There is a finger's width of space between the back of the knee and the edge of the seat.

If the seat is too long, it presses into the back of the knees, blood pools, and the legs go numb. Therefore, adjustable seat depth is almost essential for shared workstations, not a luxury.

2. Backrest

A rigid backrest is detrimental in the long run. Standards require a shape that supports the lumbar spine. But movement is crucial: a good synchronous mechanism ensures that the seat and backrest move together. They remain in motion instead of being stuck in one position all day. Your back needs precisely this alternation between leaning back and sitting upright.

3. Armrests

Armrests aren't just for show. When properly adjusted, they significantly relieve strain on the shoulders and neck. Your forearms can rest comfortably, and your shoulders stay down instead of unconsciously hunching up. If armrests are missing or too high/low, you'll compensate with muscle power. You rarely notice this after five minutes, but it becomes very clear after five months.

4. Safety and stability

A few points may seem unremarkable, but they are crucial: A five-star base ensures stability, and suitable casters for carpet or hard floors prevent unwanted rolling. This also translates into a directly measurable cost saving: A chair that wobbles or breaks after two years needs to be replaced. A solid, standard-compliant chair ideally lasts five to ten years.

Buying advice: How to recognize genuine quality

Terms like "ergonomic," "orthopedic," or "gaming-optimized" are hardly protected by law. Anyone can print them on the packaging. What you should look for instead:

• Does the data sheet or the manufacturer's website clearly state "tested according to DIN EN 1335"?
• Is there a GS mark or a comparable independent certification mark?
• Are the adjustment ranges (seat height, seat depth, backrest, armrests) clearly documented?

If this information is completely missing, I would be skeptical – especially in a professional setting.

💡 Pro tip:
Turn the chair around in the showroom and look at the sticker under the seat. There you will often find standards, test marks and manufacturer information that have been deliberately downplayed in the brochure.

The three most common mistakes when buying a chair

⚠️ Attention:
If you avoid these three mistakes, you'll already be a big step ahead of many companies:

• Buying a chair based solely on looks: The chair must suit your body, not just the wall color. A designer piece that can't be adjusted is simply a bad purchase for the workplace.
• Saving in the wrong place: An 80-euro chair may look good on the bill, but if it wobbles after a year, needs to be replaced, or causes downtime even before then, it ends up being more expensive than a solid, standard-compliant chair in the mid-three-figure range.
• No instruction: Even the best DIN-compliant chair is useless if no one knows how to adjust it correctly. Plan five minutes per person for setup – it pays off in the long run.

Special case: DIN EN 1335 vs. NPR 1813 – who even cares?

If you delve deeper into ergonomic chairs , you will sooner or later come across NPR 1813. This is a Dutch practice guideline with even larger adjustment ranges, especially for very tall people.

What does that mean for you?

• For an estimated 90 percent of German offices , DIN EN 1335, Type A is perfectly adequate – and the gold standard.
• If you have many employees who are significantly taller than 1.90 m, chairs that also meet the requirements of NPR 1813 may be useful.

Unless you have an exceptionally large workforce, you can safely dismiss NPR 1813 as "nice to know". What remains crucial is compliance with DIN EN 1335 plus the GS mark.

Conclusion: An investment in your health – and in your wallet

Whether you are setting up 50 workplaces as an employer or “just” looking for a chair for your home office: If you adhere to clear standards, you reduce two risks at once: back problems for users and bad investments in the budget.

The Sihoo Doro C300 , for example, proves that certified safety doesn't have to be unaffordable. With top marks in German tests ( 1.5 at CHIP, 1.3 at Testsieger.de ) and international certifications such as BIFMA and SGS, it delivers precisely the reliable quality that counts in everyday professional use.

When you add up sick days, dissatisfaction and durability, a thoroughly tested chair is almost always the cheaper solution in the end – even if the first glance often only focuses on the price.