Free · Measurement and planning

Battery Energy and Drone Duration

Estimate constant-load flight duration from usable battery capacity, nominal voltage, aircraft mass and watts per kilogram.

  • Formula & worked example
  • Private in your browser
  • No signup
Go to tool

Calculator inputs

Loading calculator…

How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

For the worked example, average_amp_draw = 10.00000000, drone_flight_time = 24.00000000.

Current = weight × watts per kg / voltage; duration hours = usable amp hours / average current.

Worked example

Enter these known values and leave the other values blank.

Battery capacity
5 Ah
Battery discharge
80 %
Battery voltage
20 V
All up weight (AUW)
2 kg
Watts to lift 1 kg
100 W
Drone flight time
24 min
Average amp draw
10 A

Assumptions and limitations

  • Constant average load and voltage model; 80% means 80% of nominal capacity is usable.
  • This estimate excludes voltage sag, reserve maneuvers, temperature and battery aging. Measure real current and retain an operational reserve.
  • Results follow the stated ideal arithmetic model. Display rounding does not change the underlying calculation.
  • Supply sufficient known values and leave the desired quantity blank. Controls retain captured inverse branches and units.
  • If a retained lock prevents a reverse calculation, unlock the quantity you want to solve before supplying the known values.
  • Domain checks operate on converted finite-precision quantities. A positive excess smaller than the arithmetic precision can round to a boundary; do not use extreme decimal precision to encode measurement uncertainty.

Common questions

What does the worked example demonstrate?

Current = weight × watts per kg / voltage; duration hours = usable amp hours / average current.

Can I change the measurement units?

Available selectors convert the entered physical quantity. Use compatible units for all related quantities.

Why can a result be blank?

A missing input, invalid denominator or underdetermined relationship cannot provide a unique finite result.

References

Use exact-sign physical domains, exact discrete counts where applicable, and documented model bounds. Source arithmetic is preserved.

Explore measurement and planning or browse all everyday life calculators.