Speed Calculator

Calculate speed, distance, and time using the fundamental motion equation. Convert between different speed units and analyze motion scenarios.

Speed Calculation

Calculate

Distance

Time

Quick Examples

Results

13.889

m/s

Speed in Different Units

13.889 m/s

50 km/h

31.069 mph

45.567 ft/s

26.998 knots

0.04 Mach

Speed Comparison

Walking:~1.4 m/s

Running:~5 m/s

Cycling:~8 m/s

Car (city):~14 m/s

Physics Facts

Speed of Light: 299,792,458 m/s (exact)

Speed of Sound: ~343 m/s (at 20°C)

Earth's Orbital Speed: ~30 km/s around the Sun

Escape Velocity (Earth): 11.2 km/s

How to Use the Speed Calculator

Step-by-Step Instructions

Select what you want to calculate from the dropdown menu
Enter the known values in the input fields
Choose appropriate units for each measurement
View the calculated result and unit conversions
Use quick presets for common speed scenarios

Calculation Types

Speed: Calculate from distance and time
Distance: Calculate from speed and time
Time: Calculate from speed and distance
Unit Conversion: Convert between speed units
Average Speed: Calculate from multiple segments

Physics Formulas and Concepts

Fundamental Formulas

Speed Formula:
v = d / t
Where v = speed, d = distance, t = time

Distance Formula:
d = v × t
Distance equals speed multiplied by time

Time Formula:
t = d / v
Time equals distance divided by speed

Average Speed:
v_avg = d_total / t_total
Total distance divided by total time

Key Concepts

Speed vs Velocity: Speed is scalar (magnitude only), velocity is vector (magnitude and direction).

Average vs Instantaneous: Average speed over a journey vs speed at a specific moment.

Relative Speed: Speed depends on the reference frame of the observer.

Terminal Velocity: Maximum speed reached when drag equals gravitational force.

Example Calculations

Example 1: Car Journey

Given: Distance = 120 km, Time = 2 hours

Find: Average speed

Calculation: v = 120 km ÷ 2 h = 60 km/h

Result: The car's average speed is 60 km/h

Example 2: Running Time

Given: Distance = 5 km, Speed = 10 km/h

Find: Time needed

Calculation: t = 5 km ÷ 10 km/h = 0.5 h

Result: It takes 30 minutes to run 5 km at 10 km/h

Frequently Asked Questions

What's the difference between speed and velocity?

Speed is a scalar quantity that only has magnitude (how fast), while velocity is a vector quantity that has both magnitude and direction. This calculator focuses on speed calculations.

How do I calculate average speed for a trip with multiple stops?

Use the "Average Speed (Multiple Segments)" option. Add each segment of your journey with its distance and time, and the calculator will compute the overall average speed.

Why is average speed different from the average of speeds?

Average speed is total distance divided by total time. The average of speeds would be adding all speeds and dividing by the number of measurements, which gives a different result.

What is Mach speed?

Mach is the ratio of an object's speed to the speed of sound. Mach 1 equals the speed of sound (~343 m/s at sea level), Mach 2 is twice the speed of sound, etc.