RC Battery Flight Time Estimator
Estimate how long a LiPo pack will realistically last in the air, based on capacity, average current draw, and a safe usable-capacity margin. Tap “How to find your average draw” if you’re not sure what number to enter.
How to find your average draw
- Best option — telemetry or a data logger. Most modern ESCs/flight controllers (or a simple watt meter inline with the pack) can log average current over a flight. That number is exactly what this calculator wants.
- No telemetry? Use the “Estimate from max current” mode below. Enter your motor/ESC’s max continuous current draw at full throttle, then estimate what percent of that you fly at on average. Mixed flying (cruise, some throttle-up, some idle/glide) is often around 40–60% of max; aggressive 3D or pattern flying can run 60–80%.
- Usable capacity. Most flyers land with 20–25% still in the pack to protect LiPo health and avoid a dead-stick landing, so the default below is set to 80% usable.
- Double-check with resting voltage. mAh estimates are useful for planning, but the safest real-world check is voltage: after landing, let the pack rest a few minutes (voltage rebounds after load is removed), then check it with a cell checker or balance charger. Don’t discharge below roughly 3.75–3.80V per cell at rest — going lower risks permanent capacity loss and shortens pack life, even if your calculated mAh said you had more left.
- First flight on a new setup? Land well before the estimated time. Your actual average draw is the least predictable on a first flight, so treat this number as an upper bound, not a target — give yourself margin until you’ve confirmed real-world performance.
Percent of the pack you plan to actually use before landing. 80% is a common safe default — but always confirm with resting voltage too, not just this estimate (see below).
First flight on a new setup? Plan to land well before this estimated time — a first flight is exactly when your average draw is least certain, so give yourself real headroom rather than flying to the calculated limit.
How it works: Flight Time = (Capacity × Usable %) ÷ Average Current Draw. This is an estimate — real-world flight time also depends on temperature, wind, flying style, and battery age/health.
Frequently Asked Questions
How much of my LiPo should I actually use per flight?
Most flyers plan around 80% usable capacity, landing with roughly 20–25% remaining. Regularly discharging a LiPo much past that shortens its cycle life and increases the risk of a dead-stick landing if your estimate is slightly off. Treat mAh as your planning number, but confirm with resting voltage after landing — don’t go below about 3.75–3.80V per cell at rest, even if the mAh math suggests you have margin left.
What’s a realistic average current draw for my setup?
It depends heavily on flying style. Gentle cruising might average 30–40% of your motor’s max current, mixed sport flying often lands around 40–60%, and aggressive 3D or pattern flying can average 60–80% or more. Telemetry or a watt meter will always be more accurate than a guess.
Why does my actual flight time not match the estimate?
This calculator assumes a constant average draw for the whole flight, but real flights vary — throttle-heavy takeoffs and climbs, temperature, wind, and battery age/internal resistance all affect real-world performance. Treat the result as a planning estimate, not a guarantee.
Does a higher C-rating give me longer flight time?
Not by itself. C-rating describes how much current a pack can safely deliver, not how much energy it stores. Flight time is driven by capacity (mAh) and your actual average draw — a higher C-rating just means the pack can handle higher bursts of current without excessive voltage sag or heat.
Should I use this for gas or glow-powered planes too?
No — this calculator is for electric setups powered by a LiPo (or similar) battery pack. Fuel-powered flight time is based on tank size and fuel burn rate, not battery capacity and current draw.