How to Read an Office Chair Spec Sheet and Spot Missing Specs
By Desk One Team | Published: 20 September 2026
Read an office chair spec sheet in a fixed order — weight capacity, gas lift, castors, base material, seat depth, adjustment ranges, mechanism type, then certification — and treat a missing line as a question for the seller rather than proof of a bad chair: across the 53 DeskOne chair models scanned in September 2026, weight capacity is published on only 6, base material on only 6, and not one page publishes a gas-lift class or a castor diameter.
Most Australian chair listings, including ours, publish a partial spec sheet. That is not usually an attempt to hide something — it is what the supplier data sheet contained. The practical skill for a buyer is knowing which lines change how a chair feels and lasts, what each line is actually measuring, and which absent lines you should refuse to guess at. This guide walks the spec sheet line by line, then gives you the exact questions to send a seller when a line is not there.
Key takeaways
- Weight capacity is published on only 6 of the 53 DeskOne chair models scanned, and every one of those 6 states 120kg — read that as a ceiling for a static, evenly applied load, not a daily target.
- 16 models mention a gas lift and 17 mention castors, yet not one publishes a gas-lift class or a castor material and diameter. These are the two most commonly absent lines on Australian chair listings, ours included.
- Exactly 7 DeskOne models carry a BIFMA claim: Ergo Flex v2 ($109), Ergo Comfort ($129), Ergo Lite ($247), Ergo Pro ($290), Grid ($614), Ultra Flex ($636) and Ultra ($734). The other 46 models make no BIFMA claim, and no claim is not a safety finding.
- "BIFMA Certified Components" is component-level wording. It is not whole-chair certification, and the two should never be read as the same thing.
- Decision rule: if a line you actually need is missing, get it in writing before you order. A change-of-mind return carries a 30% restocking fee with freight at your cost, so one email beats one return.
The eight lines that decide the chair
Everything else on a chair listing — upholstery colour, headrest shape, marketing adjectives — moves comfort at the margins. These eight lines move fit, durability and whether the chair can be repaired instead of replaced.
| Spec line | What it actually tells you | What a missing line means |
|---|---|---|
| Weight capacity | The supplier's tested static load ceiling for the whole chair | Ask before ordering if you are near any published figure; do not assume a number |
| Gas lift | How the seat height is powered, and whether the cylinder can be replaced | Very common gap — ask for class, test standard and stroke |
| Castors | Whether the chair will roll or scuff on your floor | Ask for material and diameter, or plan to swap them |
| Base material | How the base behaves under load and knocks, and its repairability | Ask; also ask the base diameter if you sit in a tight corner |
| Seat depth | Usable thigh support from the seat front to the backrest | Ask for a measured figure, or sit in it before you commit |
| Adjustment ranges | Whether the chair fits your body, not just that it "adjusts" | Ask for minimum and maximum values, not feature names |
| Mechanism type | How the seat and back move together and what locks | Ask which mechanism and how many lock positions |
| Certification | Which standard was tested, and whether at chair or component level | Absence is not a defect — but never read it as certification either |
Weight capacity: what "120kg" is measured as
A published weight capacity is a supplier test figure for the assembled chair under load applied down through the seat. It is a ceiling for static, evenly distributed weight — it does not describe dropping into the seat, rocking back hard, leaning on one armrest, or two people perching on the same seat. The figure is also governed by the weakest part in the load path, usually the gas cylinder and the base, which is exactly why the capacity line and the gas lift and base lines should be read together rather than separately.
On DeskOne chair pages the figure appears on only six models, and all six state 120kg: Comfort Leather ($327), Essential ($279), Prime ($439), Prestige ($543) and Luxura Elite ($519, currently out of stock) are among them. The remaining models in the range do not publish a capacity at all. The right move if you are within reach of a published number, or if the chair will be shared across shifts, is to leave headroom rather than sit at the limit, and to ask us for the supplier figure on the specific model instead of borrowing a number from a different one. If you need capacity beyond the published figures, start with our heavy-duty office chair capacity guide and confirm the model-specific figure with us before ordering.
Gas lift, castors and base material: the three lines most often absent
Gas lift. Australian listings usually advertise a gas lift by a class number, most often Class 3 or Class 4. A class is a grading of the cylinder against a cycle-and-load test regime run by the cylinder manufacturer's test house, so the number is only meaningful alongside the standard it was tested to. Sixteen DeskOne models mention a gas lift; none publishes a class. When the class is absent, ask three things: which class and to which test standard, what the cylinder stroke or seat height range is, and whether it is a standard-taper replaceable cylinder — because a replaceable cylinder turns an ageing, sagging chair into a cheap repair instead of landfill.
Castors. Seventeen models mention castors; none publishes material or diameter. Hard floors and carpet want different castors, and this is the one spec you can change yourself after delivery, so it should never decide a purchase on its own. We cover the choice properly in our guide to office chair castors for hard floors and carpet — read that, then simply ask us which type ships on the model you are looking at.
Base material. Base material appears on only six chair models. When the line is present it names what the base is made from — typically a reinforced nylon or a metal base — which is what governs how it copes with load and knocks, and whether a cracked base can be swapped. When it is absent, ask for the material and, if your chair lives in a tight corner or under a fixed-height desk, the base diameter as well.
Seat depth, adjustment ranges and mechanism type
Seat depth measures usable thigh support from the front edge of the seat to the backrest. Too deep and the seat front presses behind your knees; too shallow and your thighs lose support. The fitting test is simple: sit back against the lumbar support and check there is a few fingers' width of clearance behind the knee. Also check whether depth is adjustable via a seat slider or fixed. If a single dimension looks out of step with the rest of a chair's measurements, treat it as a possible typo and ask for a re-measure — we do the same with our own listings, and we would rather re-measure a figure than repeat it.
For adjustment ranges, the feature name tells you almost nothing. "Height adjustable" and "3D armrests" are not specs; a minimum and maximum are. Ask for the seat height range, the armrest height range, the backrest recline range and whether recline locks or only tensions. Tall and short buyers should treat these ranges as the deciding lines on the whole sheet — our guide to office chairs for tall people shows why the same chair fits one body and fails another.
Mechanism type is the line most listings compress into one word. A synchro-tilt moves seat and back together at a fixed ratio; a simpler back-tilt mechanism moves the backrest alone; a multifunction mechanism adds independent seat and back control. What matters is which one it is, how many positions it locks in, and whether the tilt tension can be matched to your body weight. If those terms are new, our explainer on ergonomic chair features defines them before you start comparing.
Certification: what a BIFMA line does and does not cover
Certification is where spec sheets get misread most often, so we will be exact about our own range. Of the 53 DeskOne chair models scanned, exactly seven carry a BIFMA claim: Ergo Flex v2 ($109), Ergo Comfort ($129), Ergo Lite ($247), Ergo Pro ($290), Grid ($614), Ultra Flex ($636) and Ultra ($734). The other 46 models make no BIFMA claim. The DeskOne chair range as a whole is not BIFMA certified, and anyone reading those seven models as a range-wide claim is reading it wrong.
Second distinction, and it matters: some of the pages carrying a BIFMA claim word it as "BIFMA Certified Components". That is component-level wording — it speaks to parts used in the chair, not to a certification of the finished chair as a whole. Whole-chair certification and certified components are different claims, and a seller should tell you which one they are making when you ask.
Third: a chair with no certification line is not automatically unsafe or poorly made. Certification is a test-and-paperwork exercise that costs money per model, and plenty of sound chairs never go through it. Absence of a certification line means you have no third-party test to lean on, so you lean on other things instead — the published capacity figure, the warranty, the returns terms and whether you can sit in the chair first. What you should never accept is a certification implied by adjacency: a brand logo, a "tested to international standards" phrase with no standard named, or one certified model being used to speak for a whole catalogue.
What to ask a seller when the line is not there
Copy these questions into an email. They are the ones we get asked, and the ones we can answer from supplier data on a specific model:
- What is the tested weight capacity for this exact model, and is it a static figure?
- What class is the gas lift, to which test standard, and is the cylinder a replaceable standard taper?
- What material and diameter are the castors as shipped, and do you stock the alternative type?
- What is the base made from, and what is its diameter?
- What is the measured seat depth, seat height range and backrest recline range?
- Which mechanism is fitted, how many lock positions does it have, and is tilt tension adjustable?
- If a certification is claimed, is it whole-chair or component-level, and which standard?
Two things make those answers worth chasing rather than gambling. Chairs carry a 1-year warranty, and our returns terms are specific: a faulty or quality issue is a full refund within 5 days, while a change of mind is a return within 7 days with a 30% restocking fee and freight at your cost. Getting the spec right before you order is materially cheaper than getting it wrong. And if you are in Brisbane, the fastest way to resolve a missing seat depth or an unclear mechanism is to sit in the chair at our Willawong showroom — Unit A4-142 Sherbrooke Rd, Willawong QLD 4110, or call 07 3879 0357 — where local pickup is also available. Stock is held in our Brisbane and Sydney warehouses rather than drop-shipped, which is why we can usually measure a chair and answer rather than forward your question offshore. Our store average across Judge.me reviews is 4.79 stars, and if you want the fuller picture of how we operate before you ask us for numbers, we have written it up in is Desk One a reliable furniture store. You can also browse the full ergonomic office chair range and compare the published lines model by model.
What does a 120kg weight capacity on an office chair actually mean?
It is the supplier's tested ceiling for static, evenly applied weight on the assembled chair, not an allowance for impact, rocking or two people on one seat. The figure is limited by the weakest part in the load path, usually the gas cylinder and base. Six DeskOne chair models publish a capacity and all six state 120kg, so if you are anywhere near that number, leave headroom and ask us for the figure on the specific model.
Is a chair unsafe if the listing does not mention a certification?
No. Certification is a paid test-and-paperwork process run per model, and many sound chairs never go through it. What the absence means is that you have no third-party test result to rely on, so you weigh the published capacity, the warranty, the returns terms and a sit test instead. What you should not do is treat a brand name or a vague "tested to international standards" phrase as if it were a certification.
Are all DeskOne chairs BIFMA certified?
No, and we would not want that read into our listings. Exactly seven models carry a BIFMA claim — Ergo Flex v2, Ergo Comfort, Ergo Lite, Ergo Pro, Grid, Ultra Flex and Ultra — and the other 46 scanned models make no BIFMA claim. Some of those seven pages word it as "BIFMA Certified Components", which is component-level and not the same as whole-chair certification, so ask us which claim applies to the model you are considering.
What should I ask if the gas lift class is not published?
Ask which class the cylinder is, which test standard that class was awarded against, what the stroke or seat height range is, and whether the cylinder is a replaceable standard taper. The class number on its own is weak information without the standard behind it. Sixteen DeskOne models mention a gas lift and none publishes a class, so this is a question we expect and can answer per model.
How do I know which castors a chair ships with?
You usually cannot tell from the listing — 17 DeskOne models mention castors and none publishes material or diameter, and the same gap is common across Australian listings. Just ask which type is fitted on the model you want. Castors are also the one spec you can change after delivery, so they should never be the reason you rule a chair out.
Can I sit in a chair before buying if the spec sheet is incomplete?
Yes, if you can get to Brisbane. Our Willawong showroom lets you test seat depth, mechanism feel and adjustment ranges directly, and local pickup is available there. If you are ordering online instead, ask for the missing figures first: a change of mind is a return within 7 days with a 30% restocking fee and freight at your cost, while a genuine fault is a full refund within 5 days.
