Skip to main content
Calculator Answers

Speed Calculator

Blake Boege
Written by Blake Boege · Founder, Calculator Answers

A speed calculator is a physics utility that computes the rate at which an object covers distance. Using the basic formula where speed equals distance divided by time, the calculator can solve for speed, distance, or duration when any two of the variables are provided. It supports a wide range of measurement systems, including metric units like kilometers per hour and meters per second, alongside imperial units like miles per hour and feet per second. It is commonly used by students, runners, and logistics planners to estimate travel rates and times.

Solve for speed, distance, or time using the basic motion formula v = d/t.

Quick Answer

Calculate speed, distance, or time using the motion formula. Enter any two values to instantly compute the third in your preferred measurement units.

What to calculate?

Time

h
m
s

Output Unit

Result

Miles per hour (mph)

66.6667

v = d/t = 100 / 1.5h

Kilometers per hour (km/h)107.29
Meters per second (m/s)29.8
Feet per second (ft/s)97.78
Knots57.93
Was this helpful?

How it works

The basic motion formula

The relationship between speed, distance, and time is one of the most fundamental formulas in physics and everyday life. If you know any two of these values, you can always find the third.

Speed = Distance / Time

Distance = Speed × Time

Time = Distance / Speed

Note: This calculates average speed, assuming a constant rate of travel.

Common Conversions

When calculating speed, making sure your units match is the most common source of error. The calculator handles these conversions automatically, but here are the standard relationships:

  • 1 mile = 1.60934 kilometers
  • 1 mph = 1.60934 km/h
  • 1 meter per second (m/s) = 3.6 km/h = 2.237 mph
  • 1 knot = 1 nautical mile per hour = 1.151 mph

Speed in Context

For reference, here are some common benchmarks of speed:

  • Walking: ~3 mph (5 km/h)
  • Running (jogging): ~6 mph (10 km/h)
  • Running (elite sprinter): ~23 mph (37 km/h)
  • Highway driving: ~65 mph (105 km/h)
  • Commercial airliner: ~550 mph (885 km/h)
  • Speed of sound (Mach 1): ~767 mph (1,235 km/h)
  • Speed of light: ~670,616,629 mph (299,792,458 m/s)

Disclaimer

This calculator provides average speeds assuming constant motion. It does not account for acceleration, traffic, rest stops, or relativity at speeds approaching light speed.

Related calculators

Related Calculators

More tools from Education

eDPI CalculatorCalculate your effective gaming mouse sensitivity (eDPI) by multiplying hardware DPI by in-game sensitivity.

Frequently asked questions

Speed is calculated by dividing the distance traveled by the time it took to travel that distance. The formula is: Speed = Distance ÷ Time (v = d/t).

If you know your speed and how long you traveled, you can calculate the distance by multiplying speed by time. The formula is: Distance = Speed × Time (d = v × t).

To find out how long a trip will take, divide the total distance by your expected speed. The formula is: Time = Distance ÷ Speed (t = d/v).

Speed is a scalar quantity, meaning it only has magnitude (e.g., 60 mph). Velocity is a vector quantity, meaning it has both magnitude and direction (e.g., 60 mph North). In everyday calculations, the terms are often used interchangeably, but in physics, the distinction is critical.

A knot is a unit of speed equal to one nautical mile per hour. It is commonly used in aviation and maritime navigation. 1 knot is approximately 1.15 mph or 1.852 km/h.

Average speed is the total distance traveled divided by the total time taken for the entire trip, including stops or slow-downs. Instantaneous speed is your speed at one exact moment (what your car's speedometer shows).

To convert miles per hour (mph) to kilometers per hour (km/h), multiply by 1.60934. To convert km/h to mph, divide by 1.60934 (or multiply by 0.62137).

The speed of sound in dry air at 20°C (68°F) is approximately 343 meters per second, which is about 767 mph or 1,235 km/h. This is known as Mach 1.