Why 250g Matters: Drone Weight Classes Explained
Cross the 250-gram line and UK drone law changes shape around you. Stay under it and you can fly in far more places, closer to people. Go over it and you inherit a bigger rulebook, wider distances to keep from bystanders, and — if you want to fly anywhere near people — extra qualifications to earn. That one number, 250g, is why so many drones are deliberately built to weigh 249g and why it should shape what you buy.
Here’s what actually changes on either side of the line, and why the featherweight class has taken over the consumer market.
The number that splits the whole rulebook
UK drone flying sits inside what the CAA calls the Open category, and the Open category is carved into three subcategories: A1, A2 and A3. In plain terms, A1 lets you fly close to people, A2 lets you fly reasonably near them with an extra qualification, and A3 keeps you well away from anyone uninvolved — out in open country, 150 metres from homes, parks and industrial areas.
Which subcategory you land in depends mostly on weight, and 250g is the first and most important cliff edge. A drone under 250g flies in A1 with almost no strings attached. From 250g upward the rules tighten quickly, and by the time you reach heavier gear you’re pushed toward A3 and its wide exclusion zones unless you hold further certificates. Nothing else in the weight table moves the goalposts as sharply as that first sub-250g threshold.
What flying under 250g actually unlocks
The real freedom that comes with staying under the line is about people, not paperwork — and it’s worth real hassle saved.
You can fly over uninvolved people. In A1 with a sub-250g drone, incidentally flying over someone who isn’t part of your flight is permitted — you must never fly over crowds or organised assemblies, but a passer-by in the park isn’t a legal crisis. Heavier drones can’t do this. From 250g up you’re keeping a horizontal gap from uninvolved people, and without an A2 qualification that gap gets large fast. That people-proximity freedom is the genuine sub-250g prize.
One thing the sub-250g class does not remove is the Flyer ID. Since 1 January 2026 anyone flying a drone of 100g or more must first pass the CAA’s online Flyer ID test — a free multiple-choice exam drawn from the Drone Code, valid five years. Nearly every popular “sub-250g” camera drone weighs well over 100g, so in practice you still sit the test. (You should read the Drone Code anyway; the rules bind you whether or not you’ve taken the quiz.)
Nor does it remove registration. If your lightweight drone has a camera — and nearly all of them do — you also need an Operator ID, the CAA’s £12.34-a-year registration displayed on the aircraft. “Under 250g means no ID at all” is a common and costly myth, so it’s worth being clear: sub-250g camera drones still need registering.
The rules that apply at every weight
Some limits don’t care what your drone weighs, so the weight-class picture isn’t complete without them:
- 120m height ceiling. You may not fly more than 120 metres (400ft) above the surface, whatever the drone weighs. A featherweight buys you no extra altitude.
- Visual line of sight. You must keep the drone in direct, unaided sight the whole flight — no flying off behind a treeline because it’s light.
- No endangering people or property. Reckless or negligent flying is an offence at any weight.
- Airport and restricted-airspace rules. Flight restriction zones around airfields apply to the smallest drone as much as the largest.
So sub-250g isn’t a licence to do anything you like — it’s a lighter set of proximity and registration rules bolted onto the same core safety code everyone flies under.
Where weight quietly creeps over the line
The catch with the 249g drones is that the figure is measured ready-to-fly, and it’s easy to nudge a drone over 250g without realising. This matters because the moment you cross the line — even by a gram — the heavier rules apply and your A1 people-proximity freedom is gone, replaced by the stricter A2/A3 distance rules.
The usual culprits are add-ons. A higher-capacity “Plus”-style battery is the classic one: it buys extra minutes but adds grams, and on some models that alone tips the drone over. Bolt-on propeller guards, and even the extra weight of ND filters or a bulkier case component, can nudge a drone that was 249g on paper past the threshold in practice. If you fly a borderline model, it’s worth weighing it as you actually fly it — battery, filters and all. Our guide to drone batteries and chargers flags which spare packs push a Mini over the line, because that trade — a few extra minutes for a heavier rulebook — is one you want to make on purpose, not by accident.
Above 250g: what you gain for the extra rules
None of this means heavier is worse. Cross the line deliberately and you generally get a bigger sensor, stronger motors that hold position in wind, longer range and a more capable camera. The trade is real freedom of the air against real capability. Which side suits you depends on whether you value flying near people with minimal paperwork or flying further and steadier with a better camera — a decision we lay out in full in sub-250g vs heavier drones.
FAQ
Is 250g the drone’s weight or including the battery?
It’s the take-off weight — the drone as it actually flies, battery, propellers and any fitted accessories included. Manufacturers quote 249g ready-to-fly for exactly this reason. If you add a heavier battery, guards or other kit, weigh the whole thing; the figure that matters to the CAA is what leaves the ground.
Do I still need to register a drone under 250g?
Yes. If the drone has a camera you need an Operator ID — the CAA’s £12.34-a-year registration, displayed on the aircraft. And since 1 January 2026 any drone of 100g or more also needs a Flyer ID, so most sub-250g camera drones need both. Only a genuinely camera-free toy under 100g escapes registration and the test entirely. Nearly every consumer drone has a camera and weighs over 100g, so in practice you register and sit the test.
What are the A1, A2 and A3 categories?
They’re the three subcategories of the Open category, defined mainly by how close to uninvolved people you may fly. A1 (which sub-250g drones fly in) allows flying near and incidentally over people. A2 needs an extra certificate and lets you fly reasonably close to people with an eligible heavier drone. A3 keeps you far from people and built-up areas — the default for heavier drones without further qualifications.
Does the 120m height limit change if my drone is under 250g?
No. The 120-metre (400ft) height ceiling applies to every drone regardless of weight, as does keeping the drone in direct line of sight. Staying under 250g relaxes the rules about flying near people — it does nothing for how high you can legally go, and it doesn’t exempt you from the Flyer ID, which any drone of 100g or more now needs.
Once the weight rules make sense, the buying decision gets easier: our roundup of the best sub-250g drones in the UK picks the models that stay under the line without cutting the wrong corners.