Velocity Calculator
Find velocity from distance and time, or from acceleration using the kinematic equations.
Please note: Results use idealised models — point masses, no air resistance, ideal gases and uniform materials. Real experiments deviate. Use these for study and estimation, not for engineering sign-off.
What the Velocity Calculator does
Velocity is displacement per unit time. When acceleration is constant, the kinematic equations let you find the final velocity either from the time elapsed or from the distance covered — useful when you know how far something travelled but not how long it took.
Formula
v = d ÷ t (average velocity)v = u + at (from time)v = √(u² + 2ad) (from distance)
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Calculate velocity from | one of 3 options | Yes | — |
| Distance | number | In some modes | Shown Calculate velocity from is Distance and time, or Calculate velocity from is Acceleration over a distance. |
| Distance unit | one of 9 options | In some modes | Shown Calculate velocity from is Distance and time, or Calculate velocity from is Acceleration over a distance. |
| Time | number | In some modes | Shown Calculate velocity from is Distance and time, or Calculate velocity from is Acceleration over time. |
| Time unit | one of 6 options | In some modes | Shown Calculate velocity from is Distance and time, or Calculate velocity from is Acceleration over time. |
| Initial velocity | number | In some modes | Shown Calculate velocity from is Acceleration over time, or Calculate velocity from is Acceleration over a distance. |
| Initial velocity unit | one of 5 options | In some modes | Shown Calculate velocity from is Acceleration over time, or Calculate velocity from is Acceleration over a distance. |
| Acceleration | number | In some modes | Shown Calculate velocity from is Acceleration over time, or Calculate velocity from is Acceleration over a distance. |
| Acceleration unit | one of 4 options | In some modes | Shown Calculate velocity from is Acceleration over time, or Calculate velocity from is Acceleration over a distance. |
How to use it
- Choose Calculate velocity from.
- Fill in the remaining inputs the form shows for your choice.
- Select Calculate.
Worked example
A sprinter covers 100 m in 9.58 seconds.
- Distance
- 100 m
- Time
- 9.58 s
v = 100 ÷ 9.58 = 10.4384 m/s, which is 37.58 km/h or 23.35 mph.
Frequently asked questions
What is the difference between speed and velocity?
Speed is how fast something moves; velocity also carries direction. A car going in a circle at a steady 50 km/h has constant speed but continuously changing velocity.
Why use the distance form instead of the time form?
Because time is often the thing you do not know. If you know a car brakes at 8 m/s² over 40 m, the distance form gives the final speed directly without solving for time first.