Drone Flight Time Calculator

Drone flight time depends on how much electrical charge a battery stores and how quickly the aircraft consumes that charge. Battery labels normally state capacity in milliamp-hours, while current draw is measured in amperes. Converting milliamp-hours to amp-hours, dividing by average amperes, and converting hours to minutes gives an ideal duration. The calculator then applies the usable-capacity percentage so the estimate does not assume a damaging full discharge. For a 5,000 mAh battery and an average draw of 20 A, the ideal duration is fifteen minutes. Using 80 percent of the rated capacity reduces the practical estimate to twelve minutes. This reserve reflects the reality that lithium-polymer batteries should land before they are exhausted. It also leaves room for voltage sag, wind, maneuvering, cell aging, temperature changes, and the difference between a printed rating and capacity actually delivered under load. Average current is the most important input and often the hardest to predict. A hovering drone may draw far less than one climbing quickly, carrying a payload, flying into wind, or making repeated high-throttle moves. Current also varies with propeller size and pitch, motor efficiency, aircraft weight, frame drag, altitude, and battery voltage. The best input comes from a flight log, current sensor, or bench measurement representative of the mission. Motor maximum-current ratings should not be used as an average unless the aircraft truly operates at that load continuously. The usable percentage defaults to 80 percent, a common planning value rather than a universal battery rule. Pilots should follow battery and aircraft manufacturer guidance, monitor cell voltage, and establish a landing threshold with a suitable margin. Older packs, cold weather, high C-rate demand, and long storage can reduce delivered capacity. Capacity can also vary between packs carrying the same label, so conservative planning is appropriate when a safe landing is critical. This result is an energy-budget estimate, not a guarantee. Validate a new setup through short controlled flights, inspect battery temperature and cell balance, and compare the predicted time with telemetry. Reduce the planned mission duration below the computed value to preserve reserves for a go-around, unexpected wind, navigation delays, and battery variation. Used with measured current and realistic capacity, the calculator offers a useful baseline for battery selection, payload decisions, and safer mission planning.