Calculate Acceleration, Velocity, Time

Calculator, how long it takes with which acceleration to reach a certain speed. If you enter two values, the third value will be calculated. The time can be specified in days (d), hours (h), minutes (m) and seconds (s). The units for speed are kilometers per hour (km/h), meters per second (m/s), miles per hour (mph), or the speed of light (c). Acceleration is given in meters per square second (m/s²) or as a multiple of the gravitational acceleration (g). It is not possible to reach or exceed the speed of light, even if values greater than 1 c can be calculated here.

a = v / t, 1 c = 299792458 m/s, 1 g = 9.81 m/s².

Example: a spaceship that had to accelerate to 90% of the speed of light (0.9 c) would need over 63½ days at a constant acceleration of 5 g. However, this spaceship would have to travel without a crew, as humans are not designed to withstand more than 1 g permanently. So if you want to fly along and therefore only accelerate at one g, i.e. 9.81 m/s², then it would take more than 318 days to reach this speed. Of course, this completely ignores the question of how larger objects such as spaceships could be accelerated to such a speed. Acceleration in space only works through recoil, so the need for fuel and energy would be gigantic, and the technical problems with something like this have not even been remotely solved.
So here is a somewhat more realistic example: a commercial aircraft takes off at 300 km/h. It takes 36 seconds to reach this speed. Therefore, it accelerates at 2.315 m/s² or 0.236 g. In combat aircraft, the value during takeoff is often around 1 g. With some flight maneuvers much higher values ​​are reached, but this can only be done by trained people. The acceleration during flight is often perpendicular to the already existing acceleration due to gravity of 1 g, so these two must be added together for the total acceleration, see Add forces.

Physics commonly uses SI units. Here is a calculator to convert units.