Projectile Flight Time Calculator

Find a projectile's flight time.

Result

2.04 s
1.02 s

How it is calculated

The tool uses the vertical part of the launch velocity: vy = v · sin θ, where v is the launch speed in m/s and θ the launch angle in degrees above horizontal. Then flight time = 2·vy / g and time to peak = vy / g, with g = 9.81 m/s² fixed. Results are in seconds, rounded to two decimals. The model assumes the projectile lands at the same height it was launched from and ignores air resistance. The speed must be above zero and the angle must be greater than 0 and at most 90 degrees; otherwise there is no result. Different planets, or a launch from a cliff or table, need other formulas.

Worked example

A ball is thrown at 20 m/s at an angle of 30 degrees. Vertical speed: 20 × sin 30° = 20 × 0.5 = 10 m/s. Time to peak: 10 / 9.81 = 1.02 s. Total flight time is twice that: 2 × 10 / 9.81 = 2.04 s. Note that the horizontal speed (about 17.3 m/s) did not enter the calculation; it only decides how far the ball travels during those 2.04 s.

Try this example →

Common mistakes

  • Entering the angle in radians. The field is in degrees, so 0.52 (30 degrees in radians) would be read as about half a degree.
  • Measuring the angle from the vertical instead of from the ground. A 60 degree launch from the vertical is 30 degrees here.
  • Using the result for a launch from a height, such as a ball thrown off a roof. The ball stays up longer than this tool says because the landing point is lower.
  • Entering speed in km/h. The tool needs m/s, so divide km/h by 3.6 first.
  • Expecting a longer airtime from a higher horizontal speed. Only the vertical part matters; with real air drag the actual time will also be somewhat shorter.

About this calculator

For projectile motion on level ground with no air resistance, the total flight time is t = 2v·sinθ/g, derived by setting the vertical displacement to zero at landing; the time to reach the peak of the trajectory is exactly half that, v·sinθ/g, since gravity decelerates and then re-accelerates the vertical velocity component symmetrically. Only the vertical launch speed component (v·sinθ) matters for timing — the horizontal component affects range, not airtime.

This is one of the first quantitative results taught in kinematics, and the same equation governs real trajectories in sports science (the hang time of a basketball shot or javelin throw), ballistics and artillery range tables, and engineering problems like sizing a water fountain jet or a projectile launcher. Physics students, coaches analyzing launch angles, and hobbyist rocketry or trebuchet builders all use it to predict how long an object stays airborne.

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Comments (1)

  • Editorial team

    Because the tool also reports time to peak, you can check any result by eye: the peak time must be exactly half the flight time. A ball launched at 20 m/s and 40 degrees gives about 2.62 s in the air and 1.31 s to the top. If a stopwatch on a real kick or throw gives something clearly shorter, air drag or a different landing height is the usual reason. What kind of launch are you modelling?

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