Time of Flight Calculator for Projectile Motion

Calculate how long a projectile stays airborne from launch speed, angle, height, and gravitational acceleration.

Projectile flight time
Uses vertical motion to solve for the positive time at which the projectile reaches ground level.

About projectile time of flight

Time of flight is the elapsed time between a projectile leaving its launch point and reaching the selected ground level. This calculator models ideal projectile motion: gravity is constant, the ground is horizontal, and aerodynamic drag is ignored. Those assumptions isolate the vertical part of motion, because horizontal speed changes range but does not determine when the object reaches the ground. The launch speed and angle are resolved into a vertical velocity using vᵧ = v sin(θ). The vertical position at time t is y(t) = h + vᵧt − gt²/2, where h is initial height and g is gravitational acceleration. Setting y to zero produces a quadratic equation. Its physically meaningful positive root is t = (vᵧ + √(vᵧ² + 2gh)) / g. When launch and landing heights are equal, h is zero and the familiar expression simplifies to t = 2v sin(θ) / g. An elevated launch remains airborne longer because it must cover the initial height before reaching the ground. Use metres, seconds, and metres per second together for consistent SI results. Standard gravity is 9.80665 m/s², while 9.81 m/s² is adequate for most classroom work. Gravity varies slightly with latitude and altitude, and other worlds require different values: about 1.62 m/s² on the Moon and 3.71 m/s² on Mars. The angle is measured upward from horizontal. A negative angle is mathematically possible for a downward launch, although practical trajectories must still begin above ground. Real balls, arrows, and other projectiles experience drag, wind, lift, and spin. Drag generally shortens the ideal flight time for a rising projectile, but its exact effect depends on shape, area, density, and speed. Treat this result as an analytical baseline rather than a substitute for a full trajectory simulation when safety or precision matters. The calculator is especially useful for physics homework, checking experiments, estimating sports trajectories, and comparing how launch angle or platform height changes airtime. Always distinguish time of flight from time to peak. Time to peak is vᵧ/g when the projectile initially moves upward, while total airtime includes the subsequent fall. For a level-to-level trajectory the two halves are symmetric, but an elevated or lowered landing point breaks that symmetry. This calculator solves the complete ground-intersection equation, so it remains valid when the projectile starts above ground.

Projectile time examples

These idealized examples use standard gravity and neglect air resistance.

Launch conditionsFlight timeInterpretation
20 m/s, 30°, 0 m2.0394 sA level-to-level launch with 10 m/s initial vertical speed.
10 m/s, 0°, 20 m2.0196 sHorizontal speed does not affect the fall time from the platform.
30 m/s, 45°, 0 m4.3262 sThe larger vertical component keeps the projectile aloft longer.

How to calculate time of flight

  1. Enter the projectile's launch speed in metres per second.
  2. Enter the launch angle measured from the horizontal.
  3. Add the launch height above the landing surface and confirm the gravity value.
  4. Select Calculate flight time to see airtime and the initial vertical speed.

Time of flight FAQ

Does horizontal velocity affect time of flight?

Not in the ideal model when the landing surface is fixed and air resistance is ignored. Only vertical velocity, launch height, and gravity determine when the projectile reaches that level.

Why is 45 degrees often used in projectile examples?

For equal launch and landing heights without drag, 45 degrees maximizes horizontal range at a fixed speed. It does not maximize airtime; a steeper angle has a larger vertical component and stays aloft longer.

Can I calculate a drop with no launch speed?

Yes. Enter zero speed and the height above the ground, and the equation reduces to the free-fall time √(2h/g).

What gravity value should I use?

Use 9.80665 m/s² for standard Earth gravity or 9.81 for typical coursework. Use a local or planetary value when the setting requires greater fidelity.

Does this calculator include air resistance?

No. Air resistance requires numerical modelling with an object's drag coefficient, cross-sectional area, mass, and atmospheric conditions.