What is the formula for speed?

Speed = Distance / Time (v = d/t). Rearranged: Distance = Speed times Time, and Time = Distance / Speed. Enter any two values to calculate the third.

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

Divide km/h by 3.6 to get m/s. Example: 90 km/h divided by 3.6 = 25 m/s. To convert m/s to km/h, multiply by 3.6.

How long does it take to travel 100 miles at 65 mph?

Time = 100 / 65 = 1.538 hours = 1 hour 32 minutes 18 seconds. The calculator displays the decimal time as hours, minutes, and seconds.

What is the difference between speed and velocity?

Speed is a scalar (magnitude only, e.g., 60 km/h). Velocity is a vector (magnitude and direction, e.g., 60 km/h north). This calculator computes scalar speed.

Speed Distance Time Calculator

How this tool fits your workflow

The speed-distance-time relationship

The fundamental relationship v = d/t connects three quantities. Given any two, the third is determined. This applies to travel planning (how long will this trip take?), physics problems (what was the average speed?), and logistics (how far can we travel in 3 hours?). Understanding this formula is foundational to physics, engineering, and everyday decision-making.

Average speed divides total distance by total time. If you drive 60 km/h for one hour then 120 km/h for one hour, average speed is 90 km/h (180 km divided by 2 hours). But if you drive each speed for 100 km, average speed is 80 km/h (200 km divided by 2.5 hours) because the slower leg takes longer.

Real-world applications of speed calculations

Travel planning relies on distance and average speed estimates. A 300-mile road trip at an average of 60 mph takes 5 hours. Accounting for traffic, stops, and varying speeds requires adjusting the average speed estimate upward to 65-70 mph in real conditions.

Physics problems use v = d/t to analyze motion. A runner covers 100 meters in 10 seconds; average speed is 10 m/s. Vehicles, projectiles, and celestial bodies all follow this relationship. In astronomy, distance = speed times time calculates light-travel distance when light travels at 299,792 km/s.

Unit conversions for speed

Common conversions: 1 km/h = 0.2778 m/s = 0.6214 mph. 1 mph = 1.6093 km/h = 0.4470 m/s. 1 knot = 1.852 km/h. Speed of light: approximately 299,792 km/s. Speed of sound in air at 20 degrees C: approximately 343 m/s = 1,235 km/h.

The calculator handles all unit conversions automatically. Enter distance in kilometers and time in hours; get speed in km/h, m/s, or mph with one click. No manual conversion math needed.

Instant physics and travel calculations

Solve speed-distance-time problems in seconds without uploading your data. Use it for homework, trip planning, fitness tracking, or any scenario where you need to calculate velocity, distance, or duration. All calculations run privately in your browser.

Frequently asked questions

What is the formula for speed?: Speed = Distance / Time (v = d/t). Rearranged: Distance = Speed times Time, and Time = Distance / Speed. Enter any two values to calculate the third.
How do I convert km/h to m/s?: Divide km/h by 3.6 to get m/s. Example: 90 km/h divided by 3.6 = 25 m/s. To convert m/s to km/h, multiply by 3.6.
How long does it take to travel 100 miles at 65 mph?: Time = 100 / 65 = 1.538 hours = 1 hour 32 minutes 18 seconds. The calculator displays the decimal time as hours, minutes, and seconds.
What is the difference between speed and velocity?: Speed is a scalar (magnitude only, e.g., 60 km/h). Velocity is a vector (magnitude and direction, e.g., 60 km/h north). This calculator computes scalar speed.