Weather & Flight
Return-to-Home Calculator
Check if your drone's battery can beat the wind home from here.
Planning aid only — not certified flight-planning software or airspace clearance. Always verify results against your own aircraft's manual and check current regulations before flying. Full disclaimer.
Flight & wind
Return-to-home assessment
SafeComfortable margin — about 43.3% battery left after landing, above your 20% reserve.
What to do
- The remaining mission time looks safe, subject to your own telemetry.
- Re-run this check if the wind picks up or you fly further from home.
What the calculator does
Enter how far the drone is from home, the battery left, your drone's rated flight time and cruise speed, the wind at your flying height, and the direction home. The calculator then:
- splits the wind into the part blowing against your flight home (headwind) or with it (tailwind), and the part blowing across it (crosswind);
- works out your ground speed home with the full wind triangle: the drone angles into any crosswind to stay on track, which costs some speed, and then loses the headwind or gains the tailwind;
- estimates the time and battery the return will take, adding extra power for a headwind;
- compares the battery left at landing with your reserve.
Why a headwind hurts twice
A headwind slows you down, so the return takes longer. It also makes the motors work harder for the whole of that longer time. The two effects multiply.
Take a drone 1.5 km from home with 45% battery left, a 30-minute rated flight time, a 10 m/s cruise speed and a 20% reserve:
| Wind on the way home | Ground speed | Time home | Battery used | Left at landing |
|---|---|---|---|---|
| Calm | 10 m/s | 2.5 min | about 8% | about 37% |
| 5 m/s tailwind | 15 m/s | 1.7 min | about 6% | about 39% |
| 5 m/s headwind | 5 m/s | 5 min | about 21% | about 24% |
| 8 m/s headwind | 2 m/s | 12.5 min | about 58% | runs out |
An 8 m/s wind is only a moderate breeze at 120 m, yet it turns a comfortable return into one the drone can't make. This is the most common way drones are lost in wind: the outbound leg, with the wind behind, feels easy.
Getting the inputs right
- Wind at your flying height, not at the ground. It is often much stronger at 100 m than at 10 m. Get it from Wind at Altitude.
- Wind direction is where the wind blows from, as in every forecast. A wind from the north (0°) is a pure headwind if home is due north of the drone.
- Direction home is the compass bearing from the drone to the home point. Most flight apps show it on the map.
- Rated flight time: use a realistic figure, not the brochure number. The Flight Time Calculator adjusts it for wind and cold.
- Cruise speed: the speed you normally fly home at, not the maximum speed of sport mode.
Plan the return before you take off
The calculator is most useful before the flight. Look at the wind direction at height and ask where "home" will be when the battery is lowest:
- Fly the first leg into the wind where you can, so the return has the wind behind you.
- Set a turn-back point by distance or battery percentage, based on a headwind return.
- Check that your drone's automatic RTH height clears obstacles, but remember that the wind is often stronger higher up.
Limits of the estimate
- It assumes steady wind. Gusts and changes in wind during the flight aren't included.
- Crosswinds lower ground speed (the drone has to angle into them), and that is included — but the extra power drawn in a crosswind is not. For a leg-by-leg breakdown use the Drone Ground Speed Calculator.
- The extra power for a headwind uses a simple approximation that is the same for every drone. Real consumption depends on your airframe, battery age and temperature.
- It assumes a straight line home. Obstacles, climbs and detours add time.
Once airborne, your drone's own telemetry and RTH system know the real battery state and should always take priority. The calculator is for planning and for sanity-checking decisions, not a replacement for them.