Velocity Calculator – Calculate Speed with Direction

Calculate velocity from displacement and time. Unlike speed, velocity includes direction – making it a vector quantity essential for physics and engineering calculations.

Displacement

Time

Output Unit

Velocity vs Speed: What's the Difference?

Understanding vector vs scalar quantities

Speed tells you how fast. Velocity tells you how fast AND which direction. Speed is a scalar (magnitude only). Velocity is a vector (magnitude + direction). This distinction matters in physics because direction affects outcomes.

Example: Round Trip

You drive 100 km north in 1 hour, then 100 km south in 1 hour. Your average speed is 100 km/h (200 km ÷ 2 h). But your average velocity is 0 km/h – you ended up where you started, so net displacement is zero.

Negative velocity doesn't mean "slower" – it means moving in the opposite direction. If positive is east, -50 m/s means 50 m/s west. The speed is still 50 m/s in both cases.

Velocity Unit Conversions

Common velocity units compared

Unit	Equals 1 m/s	Common Use
m/s	1 m/s	SI unit, physics
km/h	3.6 km/h	Road speeds (most countries)
mph	2.24 mph	Road speeds (US, UK)
knots	1.94 knots	Aviation, maritime
ft/s	3.28 ft/s	Engineering (US)
Mach	~0.0029 Mach	Aircraft speeds

Mach 1 = speed of sound ≈ 343 m/s at sea level. Varies with temperature and altitude.

Typical Velocities in Nature and Technology

Reference values for context

Object/Phenomenon	Velocity	Context
Walking human	1.4 m/s (5 km/h)	Casual walking pace
Sprinting human	10 m/s (36 km/h)	Usain Bolt's top speed
Highway car	28 m/s (100 km/h)	Typical highway speed
Commercial jet	250 m/s (900 km/h)	Cruising speed
Speed of sound	343 m/s (1235 km/h)	At sea level, 20°C
Earth orbiting Sun	29,780 m/s	Average orbital velocity
Light (vacuum)	299,792,458 m/s	Universal speed limit

Frequently Asked Questions

Can velocity be negative?

Yes. Negative velocity means moving in the opposite direction from your defined positive axis. If you define east as positive, a car going west at 50 km/h has velocity -50 km/h. The speed (magnitude) is still 50 km/h.

What's the difference between average and instantaneous velocity?

Average velocity = total displacement ÷ total time. Instantaneous velocity = velocity at a specific moment. Your car's speedometer shows instantaneous speed. If you drive 100 km in 2 hours, your average velocity is 50 km/h, even though you varied speed throughout.

How is acceleration related to velocity?

Acceleration is the rate of change of velocity. a = Δv / Δt. Positive acceleration means velocity is increasing. Negative acceleration (deceleration) means velocity is decreasing. An object can have zero velocity but non-zero acceleration (like a ball at the top of its trajectory).

Why use displacement instead of distance?

Displacement is the straight-line change in position (a vector). Distance is the total path length traveled (a scalar). Velocity uses displacement because it describes how position changes. A race car completing a lap has traveled distance but zero displacement – and therefore zero average velocity.

What is terminal velocity?

Terminal velocity is the constant speed a falling object reaches when air resistance equals gravitational force. For a skydiver in belly-down position, it's about 55 m/s (200 km/h). In a head-first dive, it can reach 90 m/s. With a parachute, it drops to about 5-7 m/s.

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Velocity Calculator – Calculate Speed with Direction

Example: Round Trip

Frequently Asked Questions

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