You Think in Stone, the Rating Plate Thinks in Kilograms
Halfway up the aisle of a builders' merchant, holding a ladder, there is a sticker that says max user weight 150 kg. You know your weight as seventeen and a half stone. Neither figure means anything to the other until one of them moves, and the question that actually matters — you, plus boots, plus a tool belt, plus the length of trunking you were planning to carry up — is not answered by either number on its own.
Load ratings are metric everywhere, because they come out of European and international test standards written in kilograms and newtons. Chairs, hammocks, trampolines, bike frames, harnesses, paddleboards and mobility scooters all carry one, and every one of those numbers is a kilogram figure printed for a market that mostly does not weigh itself that way.
What a Load Label Is Actually Telling You
It usually means you plus everything you carry
It assumes you are not bouncing
Sometimes it covers the whole assembly
It comes from a test, not a guess
Checking Yourself Against a Rating Before You Commit
The useful output is not your weight in kilograms. It is the gap between your weight and the plate.
Put your stone figure in the left field
Type it as a decimal — 17.5 for seventeen and a half — and the kilogram value appears while you type, with no button to press. A comma works instead of a dot and spaces inside the number are ignored.
Subtract the result from the rated figure
17.5 st is 111.1 kg. Against a 150 kg plate that leaves 38.9 kg of headroom, which has to cover boots, clothing, a belt of tools and anything you are carrying up with you.
Flip it to read a spec sheet in stone
Both fields accept typing, so a rated kilogram figure can go straight into the right-hand one. The swap button (↔) reverses the pair when you are working through a page of product specs rather than one label.
Copy the clean number into your query
The copy button on each field gives the bare digits with no unit and no thousands spacing, ready for an email to a supplier or a comparison sheet. Ctrl + C over a selection inside the field does the same.
If the margin looks thin, weigh the kit rather than estimating it. A loaded tool belt, work boots and a hard hat together run well into double figures in kilograms, and that is before anything goes over a shoulder.
Max-User-Weight Ratings on Kit You Already Own
Typical published ratings, converted both ways. Figures vary between makers and models, so always read the plate on the item in front of you rather than trusting a category.
| Equipment | Rated figure (kg) | Same in stone | What the rating covers |
|---|---|---|---|
| Ladder or step, EN 131 | 150 kg | 23.6 st (23 st 9 lb) | Total load: user, clothing, tools and materials |
| Task chair, standard office spec | 110 kg | 17.3 st (17 st 5 lb) | Heavy-duty ranges are separately rated, often 150 kg |
| Garden trampoline | 100 kg | 15.7 st (15 st 10 lb) | A resting figure — bouncing multiplies the force |
| Camping hammock, single | 136 kg (300 lb) | 21.4 st (21 st 6 lb) | Straps and carabiners carry their own separate ratings |
| Carbon road bike, system weight | 120 kg | 18.9 st (18 st 13 lb) | Rider plus bike plus bags, not the rider alone |
| Fall-arrest harness, EN 361 | 140 kg | 22.0 st (22 st 1 lb) | User with tools; the anchor and lanyard are rated apart |
| Inflatable paddleboard, all-round | 130 kg | 20.5 st (20 st 7 lb) | Paddler, board contents and any dry bag aboard |
| Mid-size mobility scooter | 160 kg | 25.2 st (25 st 3 lb) | Occupant plus shopping; affects range and gradient too |
Handy When You Are Reading Spec Sheets
Answers while you type
Each keystroke updates the other box, so running through several stone figures for different members of a household takes seconds.
Works from either end
Type a stone figure on the left or a rated kilogram figure on the right; the swap button turns the whole page around when the source data changes unit.
Pounds and tonnes in the same list
The searchable dropdowns hold all 18 weight units, which covers an American spec quoted in pounds and a load figure given in tonnes.
Clean kilograms for a clinic form
Copy strips the unit and the spacing, so the figure drops cleanly into a comparison table, an order note or a message to a retailer.
Questions About Load Ratings and Safe Limits
Does "max user weight" include my clothes, boots and tools?
On access equipment, yes. The EN 131 ladder figure is a total load — the person and everything on or with them — so a bare body weight comparison flatters you by whatever your boots, belt and cargo come to. Seating and leisure gear vary more: some makers state a user weight and expect ordinary clothing, others declare a total. Where the wording is vague, treat it as a total, and where an item is meant to carry cargo separately, look for a second figure covering it. Adding fifteen to twenty kilograms of allowance before you compare costs nothing and is usually about right for a working set-up.
Why does a hammock or trampoline fail well under its rated weight?
Because a person standing still and a person landing are different loads. A rated figure is normally a static one, and any deceleration adds force on top: dropping into a hammock, a bounce on a trampoline bed or a jolt on a stepladder can momentarily present several times the standing figure to the fixings. Ropes, straps and stitched webbing are also the parts that age fastest, losing strength to sunlight, damp and abrasion long before the metalwork does. A dynamic use pattern deserves a rating with a wide margin, not one you are already close to.
There is a safety factor built in, so can I go slightly over?
The margin is real, but it is already spoken for. It exists to absorb manufacturing variation, wear, damage you have not spotted, imperfect footing, off-centre loading and the shock forces above — not to give the user a private allowance on top. Test protocols typically apply a multiple of the declared figure, and a product only has to survive that; nothing promises the specimen in your hands is at the strong end of the batch. Treating the declared number as the ceiling is the whole point of it being declared.
What is a bike's system weight and how do I compare it with mine?
It is the combined figure for rider, bicycle and everything carried, quoted because the frame, wheels and fork are stressed by the total mass rather than by the person alone. To use it, take your stone figure in kilograms, add the machine — a road bike around 8 kg, a hybrid nearer 12, an e-bike often over 20 — then add bottles, bags, lock and pump. Some makers publish separate ceilings for rider, luggage and total, and rack or pannier limits sit on top of that. Wheels tend to be the first component with a lower published limit than the frame.
What actually happens if I exceed the rating?
Usually nothing dramatic on day one, which is why the practice persists. What changes is the arithmetic underneath: components sit closer to their fatigue limit, so cracks start earlier, welds and stitching age faster, and the item's margin for a bad moment shrinks. The visible consequences arrive elsewhere — a warranty claim declined, an insurer asking about the declared limit after an accident, and in a workplace an employer's duty to provide suitable equipment left unmet. Where a rated item is genuinely too light for you, heavy-duty versions of almost all of these exist and are marked with a higher figure.
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