Search for drone licensing rules in Korea and you'll find a table running from Class 1 to Class 4. The dividing line is maximum takeoff weight. Under 250 grams, you need no license at all. Cross 250 grams and you need online training; cross 2 kilograms and you need a written exam plus logged flight hours.
The table is clear enough. What it leaves out is the one thing anyone building an FPV drone actually needs: nobody tells you how much your own aircraft weighs.
A store-bought drone has the weight printed right on the box. A 5-inch FPV drone doesn't come in a box at all. You pick the frame, the motors, and the battery separately and build it yourself, which means the weight is decided the moment you choose those parts — and doing that math is on you.
The Weight Is Set the Moment You Pick the Parts
Finishing the build and then putting it on a scale gets the order backwards. By that point you've already spent the money on every part.
Three components do most of the work. The frame sets the aircraft's overall size, the battery is the single heaviest part, and the four motors come next. Everything else is light on its own, but with a dozen-plus other components bolted on, the total adds up to more than you'd think.
There's a trap here. The regulation isn't concerned with the bare airframe — it's concerned with maximum takeoff weight: the weight of the aircraft as it actually flies, battery inserted, camera mounted, ready to launch. Leave the battery out of your parts-weight tally and the whole calculation is wrong.
Two Thresholds: 250 Grams and 2 Kilograms
There are two thresholds, and what falls between them matters.
A 5-inch FPV drone usually lands in the middle band — over 250 grams, but nowhere close to 2 kilograms. It's tempting to conclude, "so online training is all I need," and move on. Two more things are worth checking first.
First, 250 grams is a lower bar than it sounds. Even a small 3-inch build can cross it if you fit a large enough battery. The only way to know is to add up your parts list.
Second, licensing is only one condition among several. There are places you still can't fly even with a license, and altitudes that require separate approval.
FPV Flying Comes With One More Requirement Beyond the License
This is where ordinary drones and FPV drones part ways.
Standard drone flight assumes the pilot keeps the aircraft in view the whole time. FPV flight doesn't work that way — you're wearing goggles and flying on the video feed the aircraft sends back. You are not looking at the aircraft.
That's why FPV flight rules require a separate visual observer — someone keeping eyes on the aircraft the whole time. Even with a license in hand, strapping on goggles and flying solo falls outside that requirement.
There's a reason this part doesn't turn up in a search. Licensing information comes from sources covering drones in general, and those sources default to assuming visual-line-of-sight flight. The FPV-specific requirement never makes it into that table.
How Not to Do This Backwards
Here's the order to check things in, before you buy a single part.
First, build a parts list and add up the weight — battery included.
Second, see which band that number falls into relative to 250 grams and 2 kilograms. If you're close to a threshold, swapping the frame or the battery to stay on the side you want is a real option — one that's only available before you've bought anything.
Third, once the band is set, check which license it requires. Class 4 means online training; Class 3 or above means a written exam plus logged flight hours — and the lead time for each is very different.
Fourth, separately from licensing, decide where you'll actually fly. Airspace restrictions run on a different axis entirely, and if you get blocked there, having a license won't give you anywhere to fly.
What happens if you follow this sequence only after finishing the build? If the weight comes in over 2 kilograms and you don't hold a Class 3 license, you're rebuilding the aircraft or waiting months. Do the math before you buy the parts, and that choice is still open to you.
What to Do Next
If you haven't built your aircraft yet, start with the parts list. Add up the weight, battery included, confirm which band you land in, and only then buy the parts.
If you've already built it, put it on a scale first. The number you get from adding up catalog specs almost never matches the real weight — solder joints, wiring, zip ties, and tape all add up too.
