Why is real flight time less than calculated?

You should never fully discharge a LiPo battery as it damages the cells and can be dangerous. Most pilots use only 80% of capacity. Additionally, current draw varies with manoeuvres, wind, and throttle changes. The usable time accounts for these factors.

How do I measure average current draw?

Use a watt meter inline between the battery and ESC during a typical flight or run. Many ESCs also log average current. Alternatively, check the motor specification for current draw at your voltage and propeller combination.

What is a safe LiPo discharge level?

Do not discharge below 3.5V per cell under load (3.7V resting). Most pilots set a timer or voltage alarm at 80% of capacity used. Over-discharging below 3.0V per cell causes permanent damage and can lead to puffing or fire.

Does throttle percentage affect flight time linearly?

Not exactly. Current draw increases more than linearly with throttle due to motor and propeller characteristics. At 50% throttle you typically draw 30-40% of full-throttle current. This calculator uses throttle as a linear approximation for average flying.

ModelCalcs

Battery Flight Time Calculator

Calculate estimated flight or run time from battery capacity, motor current draw and efficiency.

Battery Capacity

Battery capacity in milliamp-hours

Average Current Draw

Average motor current at full throttle

Battery Voltage

Nominal battery voltage (cell count)

Model Type

Type of RC model for reference

Average Throttle

Average throttle during typical use

How We Calculate This

Flight Time Formula

Raw time = Battery capacity (mAh) / (Average current (A) x 1000) x 60

Usable time = Raw time x Usable capacity % x Efficiency factor

The usable capacity (default 80%) prevents over-discharging the LiPo. The efficiency factor accounts for real-world losses from wind, manoeuvres and throttle variation.

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Always verify quantities before purchasing materials.