Drone Battery Capacity Calculator
Calculate the battery capacity your drone needs for a target flight time.
Enter motor count, current draw, and safety reserve to size your battery correctly.
Drone Battery Sizing
The battery is one of the most critical components in a drone build. Too small and flight time suffers; too large and the extra weight reduces efficiency.
Formula: Required mAh = (Total Current Draw × Flight Time in minutes) / 60 × 1000 / (1 - Reserve%)
Where:
- Total Current Draw (A) = Number of motors × Current per motor at hover
- Flight time = desired flight time in minutes
- Reserve = safety buffer (typically 20–30%; never fully discharge a LiPo)
Watt-hours (energy): Wh = mAh × Voltage / 1000
Current draw by drone type:
- Micro / Tiny Whoop (2–3 inch): 2–6A per motor at hover
- 5-inch freestyle FPV: 10–20A per motor at hover
- 7-inch long-range: 8–15A per motor at hover
- Large hex/octocopter: 15–30A per motor at hover
- Cinema drone (heavy payload): 20–40A per motor at hover
Battery cell voltage:
- 1S = 3.7V nominal (3.0V min, 4.2V fully charged)
- 3S = 11.1V nominal
- 4S = 14.8V nominal
- 6S = 22.2V nominal
LiPo discharge rating (C rating): The C rating multiplied by the capacity in Ah gives the maximum continuous current. A 1500mAh 50C battery can supply: 1.5 × 50 = 75A continuous.
Practical notes: LiPo batteries should never be discharged below 3.5V per cell (storage) or 3.0V per cell (absolute minimum). Always monitor cell voltage with a buzzer or battery alarm during flight. Flying aggressively increases current draw significantly above hover current — add extra buffer.