Velocity Calculator
Velocity is a vector quantity describing the rate of change of position, measured in meters per second (m/s). Speed is its scalar counterpart — the magnitude of velocity. The fundamental equation v = d/t relates velocity, distance, and time: knowing any two allows you to find the third. For objects with constant acceleration, the four kinematic equations connect initial velocity (u), final velocity (v), acceleration (a), displacement (s), and time (t). These equations are foundational in classical mechanics, used everywhere from analyzing car crashes to designing rockets. This calculator handles all common velocity problems with automatic unit conversion between m/s, km/h, mph, and ft/s.
speed v = d / t
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Velocity
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calculate Kinematic Equations
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Result
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swap_horiz Speed Unit Converter
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Enter a speed to convert
lightbulb Tips
- •v = d/t — velocity = distance ÷ time (m/s)
- •Kinematic eq 1: v = u + at (constant acceleration)
- •1 m/s = 3.6 km/h = 2.237 mph
- •Speed of sound = 343 m/s at 20°C sea level
How to Use This Calculator
Choose a Calculation Mode
Select Basic (v = d/t) to find velocity, distance, or time. Choose Kinematics for constant-acceleration problems. Use Unit Converter to convert between m/s, km/h, mph, and ft/s.
Select What to Solve For
Pick the unknown variable you want to calculate — velocity, distance, time, acceleration, or displacement — from the 'Solve For' dropdown.
Enter the Known Values
Fill in the values you know. For Basic mode enter distance (m) and time (s). For Kinematics enter any combination of u, v, a, t, or s. Units can be changed where applicable.
Read Your Results
Results appear instantly in multiple units (m/s, km/h, mph, ft/s). The formula used is shown below the result so you can verify the calculation.
The Formula
The basic velocity formula v = d/t states that velocity equals distance divided by time. For 1 m/s, an object travels 1 meter every second — equivalent to 3.6 km/h or 2.237 mph. The kinematic equations extend this to accelerating objects: v = u + at gives final velocity after time t; v² = u² + 2as finds final velocity after displacement s without needing time; s = ut + ½at² gives displacement during acceleration. These four equations are the complete toolkit for constant-acceleration problems in physics and engineering.
v = d/t | v = u + at | v² = u² + 2as | s = ut + ½at²
lightbulb Variables Explained
- v Final velocity (m/s)
- u Initial velocity (m/s)
- d / s Distance or displacement (m)
- t Time (s)
- a Acceleration (m/s²)
tips_and_updates Pro Tips
Velocity is a vector (has direction); speed is a scalar (magnitude only). Average velocity = displacement / time; average speed = total distance / time.
Unit quick-convert: multiply m/s by 3.6 to get km/h; multiply mph by 0.447 to get m/s; multiply km/h by 0.621 to get mph.
The kinematic equations only apply when acceleration is constant. For variable acceleration you need calculus (integration).
0 to 100 km/h in 5 s means acceleration ≈ 5.56 m/s² — about 0.57g. Fighter jets sustain 9g (88 m/s²) in turns.
Speed of sound ≈ 343 m/s (1235 km/h) at sea level; speed of light = 299,792,458 m/s (exactly, by definition).
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All formulas verified against official standards.