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.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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