Velocity
Solve v = d/t for velocity, distance, or time. Free calculator with unit conversions and step-by-step working.
Key formula
v = d / t
How do you calculate velocity?
Average velocity is displacement divided by time: v = d / t. Convert distance and time to the same unit system first (school SI default is metres and seconds), then divide. State direction or a sign when the question asks for velocity rather than speed.
About this tool
Velocity tells you how quickly displacement changes with time. This tool helps users solve for speed-related motion quantities while keeping the equation structure visible, which is useful for both homework and intuition.
How to use this calculator
- Choose the variable you want to solve for and confirm which values are already known.
- Enter inputs in consistent units before calculating so the formula is applied correctly.
- Check whether the result is physically reasonable by comparing it with the size of the inputs.
- Use the step-by-step breakdown to see how the equation was rearranged and evaluated.
Worked examples
Example 1: 120 m in 1 minute
A runner covers 120 m due north in 1.0 minute. Convert time first: 1.0 min = 60 s. Then v = d / t = 120 m / 60 s = 2.0 m/s north. Skipping the conversion and using 120 / 1 gives 120 m/min — a different quantity that markers usually do not want when the answer unit is m/s.
Example 2: 36 km in 1 hour
A car travels 36 km due west in 1.0 hour on a straight road. (a) With consistent km–h units: v = 36 km / 1.0 h = 36 km/h west. (b) In SI: 36 km = 36 000 m and 1.0 h = 3600 s, so v = 36 000 / 3600 = 10 m/s west. Quick check: 36 ÷ 3.6 = 10 m/s.
Frequently asked questions
What is the formula for average velocity?
Average velocity is v = d / t, where d is displacement (change in position) and t is the time interval. Rearrangements are d = v × t and t = d / v. Use consistent units before you divide.
What is the difference between speed and velocity?
Speed is a scalar (magnitude only). Velocity is a vector (magnitude and direction). They match on a straight one-way path with no reversal. On a round trip, average speed can be high while average velocity is near zero because net displacement is small.
How do I convert km/h to m/s for velocity problems?
Divide km/h by 3.6 to get m/s (or multiply by 1000/3600). Multiply m/s by 3.6 to get km/h. Convert before dividing distance by time so you do not mix kilometres with seconds.
When should I use v = d/t instead of kinematics (SUVAT)?
Use v = d / t for average velocity when you know displacement and time, or rearrangements of that pair. Switch to the kinematics calculator when constant acceleration is involved and you need a final velocity, initial velocity, or another SUVAT unknown.
Why is my velocity answer wrong even if I divided correctly?
Most wrong answers are unit mistakes: time left in minutes while reporting m/s, km mixed with seconds, or path length used when the question wants displacement. Also check whether the mark scheme expects a direction or sign for velocity.