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Velocity Calculator

Calculate speed or acceleration by entering distance and time, or velocity change.

Input Information

Result

Press Calculate to see the result.

Velocity Calculator is an essential physics tool that accurately calculates an object’s speed and acceleration. It covers average velocity and acceleration — two core concepts widely used from everyday life to specialized fields.

Velocity is the rate of change of an object’s position, representing the distance traveled per unit time. Its standard unit is meters per second (m/s), and is a physical quantity used very frequently in daily life such as car speed, running speed, and wind speed. Velocity is a vector quantity that includes direction, so the same speed with a different direction is a different velocity.

Acceleration is the rate of change of velocity, indicating how much the velocity changes per unit time. Its unit is meters per second squared (m/s²). It plays an important role in a car starting off, decelerating when braking, and free-fall motion; positive acceleration means increasing speed, while negative acceleration means deceleration.

This calculator serves as an educational tool that helps students intuitively understand kinematic concepts, and as a practical tool that provides engineers with accurate velocity and acceleration data for vehicle performance analysis, traffic system design, aerospace projects, and more.

Term Glossary

Velocity
Change in position per unit time; a vector quantity that includes direction, with unit m/s.
Acceleration
Change in velocity per unit time, with unit m/s².
Speed
A scalar quantity without direction, meaning only the magnitude of velocity.

  1. Enter the distance traveled (meters m or kilometers km).
  2. Enter the time taken (seconds s or hours h).
  3. Click calculate and the velocity is computed automatically.
  4. Read the result and check the unit (m/s, km/h).

100 m in 10 s

If a runner covers 100 m in 10 seconds, the velocity is 100 ÷ 10 = 10 m/s.

100 km in 2 h

If a car travels 100 km in 2 hours, the velocity is 100 ÷ 2 = 50 km/h.

300 m in 60 s

If 300 m is covered in 1 minute (60 s), the velocity is 300 ÷ 60 = 5 m/s.

Average Velocity Formula

Calculate velocity when you know the time taken to travel a certain distance.

v=dtv = \dfrac{d}{t}
  • v is velocity, with unit m/s.
  • d is distance, with unit meter (m).
  • t is time, with unit second (s).

Acceleration Formula

Calculate acceleration from initial velocity, final velocity, and time.

a=v−v0ta = \dfrac{v - v_0}{t}
  • a is acceleration, with unit m/s².
  • v is the final velocity, with unit m/s.
  • v₀ is the initial velocity, with unit m/s.
  • t is time, with unit second (s).

Example

For example, if a car travels 100 m in 5 seconds?

v=100 m/5 s=20 m/s  (72 km/h)v = 100\,\text{m} / 5\,\text{s} = 20\,\text{m/s}\;(72\,\text{km/h})

The car moves 20 meters per second, which equals 72 km/h.

Key Formulas

  • Average velocity: v = d/t (distance/time)
  • Acceleration: a = (v - v₀)/t (rate of velocity change)
  • Final velocity: v = v₀ + at (uniform acceleration)
  • Distance: d = v₀t + ½at² (uniform acceleration)

Unit Conversion Tips

  • 1 m/s = 3.6 km/h (to km/h: multiply by 3.6)
  • 1 km/h = 0.2778 m/s (to m/s: divide by 3.6)
  • 1 mph ≈ 0.4470 m/s (mph → m/s)

⚠️ Difference Between Velocity and Speed

In physics, velocity is a vector quantity that includes direction, while speed is a scalar quantity without direction. For example, a runner moving north at 10 m/s and one moving south at 10 m/s have the same speed but different velocities.

Real-Life Applications

  • Traffic engineering: road design, traffic flow analysis, signal system design
  • Sports: athlete performance analysis, training program design
  • Aerospace: aircraft takeoff speed, satellite orbital speed calculation
  • Automotive engineering: 0→100 km/h acceleration time, braking distance calculation

Educational Use

This calculator is useful for understanding the following concepts.

  • Constant velocity motion: uniform linear motion when acceleration is zero
  • Uniform acceleration motion: free fall using gravitational acceleration (9.8 m/s²)
  • Velocity-time graph: slope is acceleration, area is distance

QWhat is the difference between velocity and speed?

Speed is a scalar quantity with magnitude only, while velocity is a vector quantity that includes direction. For example, 10 m/s north and 10 m/s south have the same speed but different velocities.

QHow do I convert m/s to km/h?

Multiply m/s by 3.6 to get km/h. For example, 10 m/s equals 10 × 3.6 = 36 km/h. To convert km/h to m/s, divide by 3.6.

QWhat is the difference between average and instantaneous velocity?

Average velocity is total distance divided by total time, while instantaneous velocity is the velocity at a specific moment. A car speedometer shows instantaneous velocity.

QHow are displacement and distance different?

Distance is the total length of the path traveled, while displacement is the straight-line distance and direction from start to end. If you return to the starting point, displacement is zero but distance is not.

QWhat units are used for velocity?

The SI unit is meters per second (m/s), while km/h, mph, and knots are also commonly used in daily life. 1 m/s = 3.6 km/h ≈ 2.237 mph.

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