How is flight time calculated?

Time in hours equals usable capacity in amp-hours divided by average current in amps. The tool converts mAh to Ah by dividing by 1000, multiplies by the usable factor, divides by current, and converts hours to minutes.

Why use a usable-capacity factor instead of the full capacity?

Discharging a LiPo to empty damages it. Pilots typically land with 20 percent left, using only about 80 percent of rated capacity. The usable factor (default 0.8) reflects this safe reserve so the estimate matches real flights.

What current draw should I enter?

Use the average in-flight current, not the peak. Hovering multirotors and cruising planes draw far less than full throttle. A power meter or flight-controller telemetry gives the most accurate average; otherwise estimate from your setup.

Does a bigger battery always mean longer flight?

Not proportionally. A larger pack adds weight, which raises the current needed to lift it, partly offsetting the extra capacity. There is an optimal pack size for each craft where added weight starts to cancel the gain in capacity.

Does this account for voltage sag or temperature?

No. It is a capacity-versus-current estimate. Cold weather, aging cells, and heavy voltage sag reduce usable capacity, so treat the result as an upper bound and keep a safety margin.

LiPo Battery Capacity & Flight Time Calculator

How long will my pack last? This calculator answers that for any RC plane, multirotor, or FPV drone by combining battery capacity with your average current draw, while reserving a safe portion of the pack you should never discharge into.

How it works

Run time is simply usable charge divided by current, with units lined up:

usable Ah = (capacity mAh / 1000) × usable factor
time (h)  = usable Ah / average current A
time (min) = time (h) × 60

The usable factor (default 0.8) keeps a reserve so you never run a LiPo flat, which would damage the cells and risk a dead-stick landing.

Example and tips

A 1500 mAh pack flown at an average 20 A draw gives (1.5 × 0.8) / 20 = 0.06 h, or about 3.6 minutes — typical for an aggressive FPV quad. The same pack on an efficient fixed-wing cruising at 5 A lasts roughly 14 minutes. Measure your real average current with an inline watt-meter once and your estimates will be far more reliable than guessing from throttle position.