A top consumer drone's radio link can reach 10 to 15 km from its controller in ideal conditions, but the law in the US and most other countries requires you to keep the drone in unaided visual line of sight. In practice that limits a legal flight to a few hundred metres, which is far closer than the radio can reach.

How far a drone can fly depends first on what kind of drone it is. Toy drones reach 50 to 300 feet. Beginner hobby drones reach 0.25 to 1 mile. Prosumer drones reach 2 to 7 miles. Enterprise and commercial drones reach 5 to 15 miles or more. The DJI Air 3S is rated up to 12.4 miles, or 20 km, and the DJI Mini 4 Pro is rated up to 10 km.

The signal system is what sets the radio range. Basic Wi-Fi drones lose connection at roughly 100 to 500 metres. DJI's OcuSync 2.0 reaches up to 10 km, and OcuSync 3.0 and 4.0 reach up to 15 km. Those are laboratory numbers measured with no obstacles, no radio interference and a clear line of sight. In real suburban or urban conditions, expect 50 to 70 percent of the rated range, so a 20 km rating becomes 10 to 14 km in practice.

Here is a worked example that shows the battery, not the radio, is usually the real limit. Take a drone with a 34-minute battery and keep a 20 percent reserve for the return trip and landing. That leaves 27.2 minutes of usable flying time. Half of that goes out and half comes back, so the outward leg is 816 seconds. Flying out at 12 metres per second, the furthest point you can reach and still return is 12 times 816, which is 9,792 metres, or about 9.8 km. The total flight distance is 12 times 27.2 minutes times 60 seconds, which is 19.6 km. Even though the radio is rated to 10 km, the battery caps the round trip at about 9.8 km, and the law caps it at roughly 500 metres of sight.

Several things shorten the range further. Buildings, trees and terrain block the signal, and other Wi-Fi networks and radio sources interfere with it. Wind and cold weather drain the battery faster, and the video feed usually drops before the control link does, because video uses the 5.8 GHz band while control uses the longer-reaching 2.4 GHz band. If the link does break, most modern drones fly themselves home automatically.

The legal limit is the one that matters most. Under the FAA's Part 107 rules in the US, and under equivalent rules in most countries, you must keep the drone within unaided visual line of sight at all times. You can only clearly see a small drone from about 500 to 600 metres away. Flying beyond that, called beyond visual line of sight, needs a specific waiver or authorisation. So the honest answer to how far a drone can fly has two parts: the radio can reach 10 to 15 km, but the law keeps you within sight, a few hundred metres away.

Q: How far can a DJI Mini 4 Pro fly from its controller?

A: Its OcuSync 2.0 link is rated up to 10 km in ideal conditions, but in suburban areas the real range is closer to 2 to 4 km, and the law still requires visual line of sight.

Q: Can a drone fly 10 miles from its controller?

A: Only enterprise or commercial drones with advanced links can reach 10 miles or more. Most consumer drones are limited to around 7 miles, and flying that far would break visual line of sight rules.

Q: Why does my drone lose signal closer than the rated range?

A: The rating is measured with no obstacles and no interference. Buildings, trees, other Wi-Fi networks and terrain all shorten the real range, often to 50 to 70 percent of the rating.

Q: What happens if a drone flies out of range?

A: The video feed drops first, then the control link. Most modern drones then trigger return-to-home and fly themselves back to the take-off point.