Estimate hover and cruise flight time from battery capacity, weight, and current draw.
Estimated Flight Time
Moderate — common for freestyle and sport flying.
Usable Battery Capacity
80% of rated capacity (LiPo safe discharge limit)
Average Current Draw
9.0A at Hover profile
Average Power Draw
133.3W average draw
Battery Energy
14.8V × 1500mAh
Estimated Hover Current
Estimated hover current at 6g/W specific thrust
Drone flight time is fundamentally an energy budget problem. Your battery stores a fixed amount of electrical energy, and your motors consume that energy at a rate determined by weight and flying style. When the energy runs out, the flight ends. The calculation follows a simple model: estimate how much current the motors draw on average, then divide the usable battery capacity by that current.
The hover current — the baseline current required to keep the drone airborne — is estimated from the all-up weight and battery voltage using a specific-thrust model. A typical multirotor achieves around 6 grams of lift per watt of electrical input, so hover power equals the weight in grams divided by 6. Dividing by voltage gives hover current in amps. A heavier drone requires more power; a higher voltage battery delivers the same power at lower current. The flight profile multiplier then scales this baseline current to match the actual flying style, from a gentle 1.2× for cruising to a demanding 3.0× for racing.
The result is an estimate, not a guarantee. Real-world flight times are typically 10–20% lower than calculated values due to battery aging, voltage sag, wind resistance, and the fact that no flight is perfectly steady-state. Use these numbers for planning and comparison rather than absolute guarantees.
All-Up Weight
Weight is the dominant factor. More weight requires more thrust, which means more current draw. Doubling the weight roughly halves your flight time (holding other variables constant). Every gram saved — lighter frame, smaller battery, removed components — directly extends flight time. The battery itself is typically 20–35% of AUW, creating a diminishing returns curve: a bigger battery adds more capacity but also more weight, reducing efficiency.
Flying Style
Aggressive throttle inputs increase current draw dramatically. A freestyle pilot repeatedly punching to full throttle may draw 80–120A in bursts, versus a slow hover at 10–15A. Over a full flight, aggressive flying can reduce flight time by 60–70% compared to gentle cruising at the same weight and battery. The flight profile presets in this calculator capture this effect.
Wind
Flying into headwinds requires the drone to tilt forward, redirecting thrust horizontally and requiring higher throttle to maintain altitude. Strong winds (15+ km/h) can reduce flight time by 15–25% compared to calm conditions. The calculator does not account for wind — add a buffer if you fly in exposed locations.
Temperature
LiPo batteries are sensitive to temperature. At 0°C, capacity can drop to 70–80% of rated values. Below −10°C some batteries refuse to discharge safely at all. High temperatures above 45°C also reduce capacity and accelerate aging. For cold-weather operations, keep batteries warm before flight and expect 15–25% shorter sessions.
Battery Age and Health
A fresh battery delivers its rated capacity. After 100 charge/discharge cycles, most LiPo cells retain 80–85% of original capacity. After 300 cycles, capacity may drop to 60–70%. Internal resistance also increases with age, causing more voltage sag under load. A calculator always assumes a healthy, new battery — older packs will deliver noticeably less flight time.
A LiPo cell has a nominal voltage of 3.7V, a full-charge voltage of 4.2V, and a safe minimum discharge voltage of 3.5V per cell. The usable capacity between 4.2V and 3.5V is approximately 80% of the rated capacity — the remaining 20% exists below 3.5V but using it damages the cells and risks thermal runaway.
The discharge curve is not linear. Voltage stays relatively flat between 4.2V and 3.7V, then drops steeply below 3.7V. In practice, the on-board voltage alarm is set around 3.5V/cell, giving a clear low-battery warning before the voltage enters the danger zone. Most FPV pilots land when their OSD reads approximately 3.6–3.7V per cell to preserve battery health.
This calculator applies the 80% rule to all estimates — the usable capacity output reflects this. If you push your battery harder (flying to lower voltages), you may get slightly more time, but at the cost of battery longevity and safety margin.
Reduce weight wherever possible
Every 100g saved can add 1–2 minutes to flight time. Use lightweight frames, remove unnecessary components, and choose the smallest battery that meets your time requirements.
Use efficient propellers
Larger, slower-spinning propellers are more aerodynamically efficient than smaller, fast-spinning ones. A 7" prop on a 5" motor frame can be 20–30% more efficient at hover than a matched 5" prop.
Fly smoothly
Smooth throttle inputs and gradual direction changes dramatically reduce average current draw. Practice altitude-hold modes before manual flying to build smooth control habits.
Maintain your batteries
Store LiPo batteries at storage voltage (3.7–3.85V/cell) when not flying for more than a few days. Avoid full charge for storage and never leave discharged batteries sitting. Good maintenance preserves rated capacity longer.
The hover current model used in this calculator is a simplified approximation. It assumes perfect propeller efficiency at 65%, ignores aerodynamic drag during forward flight, and uses nominal cell voltage rather than a real discharge curve. These simplifications make the math tractable and the result useful for planning, but they mean calculated times are consistently optimistic.
In real-world testing, most builds achieve 80–90% of the calculated hover time and significantly less during active flying. Racing builds operating at the highest current multipliers often see 60–70% of the calculated value due to voltage sag reducing effective voltage below the nominal 3.7V/cell assumed in calculations.
For the most accurate predictions, use the Custom flight profile and enter your measured average current draw from a Betaflight Blackbox log or OSD energy counter. Actual current measurements from your specific build will produce estimates accurate to within 5–10% of real-world flight time.