Speed Distance Time Calculator
Calculate speed, distance, or time from any two known values. Free online speed calculator with unit conversions, charts, and step-by-step formula breakdown.
About This Calculator
Our Speed Distance Time Calculator is a versatile tool that computes any missing value — speed, distance, or time — when you provide the other two. Whether you are planning a road trip, training for a marathon, studying physics, or simply curious about how fast you are moving, this calculator gives you instant, accurate results with full unit support.
The calculator is built on the fundamental formula speed = distance / time. From this single equation, we can derive all three forms:
- Speed = Distance ÷ Time — used when you know how far and how long
- Distance = Speed × Time — used to estimate travel range or trip length
- Time = Distance ÷ Speed — used to plan journey duration or ETA
You can mix and match units across the metric and imperial systems. For example, enter distance in miles, time in minutes, and get speed in km/h — the calculator handles all conversions automatically behind the scenes. The unit comparison chart shows your speed converted to m/s, km/h, mph, ft/s, and knots for easy reference.
Regional Notes
India: Road speeds are typically measured in km/h. The default units are set to kilometers for distance, hours for time, and km/h for speed. The Indian speed limit on highways is generally 80-120 km/h depending on the road type.
United States: Road speeds are measured in miles per hour (mph). Distance defaults to miles and speed to mph. The US interstate speed limit is typically 55-75 mph. This calculator also supports feet per second, which is commonly used in US engineering and sports.
United Kingdom: Road speeds are measured in mph on public roads (the UK uses imperial for speed limits but metric for most other measurements). UK motorway speed limits are 70 mph. The calculator supports both mph and km/h for convenience.
For runners and cyclists, pace is often expressed as minutes per kilometer or minutes per mile. You can use this calculator to find your average speed, then convert to pace by dividing 60 by your speed in km/h or mph.
Frequently Asked Questions
How does the speed distance time calculator work?
Enter any two values — distance, time, or speed — and the calculator computes the third using the formula speed = distance / time. You can mix units across metric and imperial systems.
What is the formula for average speed?
Average speed is calculated as total distance traveled divided by total time taken: speed = distance / time. For example, driving 150 km in 2 hours gives an average speed of 75 km/h.
How far will I travel at 60 mph for 2 hours?
At a constant speed of 60 mph for 2 hours, you will travel 120 miles. This uses the formula distance = speed × time.
What is the difference between speed and velocity?
Speed is a scalar quantity that measures how fast an object is moving without regard to direction. Velocity is a vector that includes both speed and direction. For example, 60 mph is a speed, while 60 mph north is a velocity.
How do I convert mph to km/h?
To convert miles per hour to kilometers per hour, multiply by 1.609. For example, 60 mph × 1.609 = 96.5 km/h. To convert km/h to mph, divide by 1.609.
How long does it take to drive 100 km at 80 km/h?
At a speed of 80 km/h, driving 100 km takes 1 hour and 15 minutes (100 ÷ 80 = 1.25 hours = 1 hour 15 minutes). Use the formula time = distance / speed.
What speed units does this calculator support?
The calculator supports kilometers per hour (km/h), miles per hour (mph), meters per second (m/s), feet per second (ft/s), and knots (kn). You can also view the result converted across all units in the comparison chart.
Can I use this calculator for walking, running, or cycling?
Yes, this calculator works for any type of movement including walking, running, cycling, driving, flying, or sailing. Simply enter your distance and time to find your average speed, or enter speed and time to estimate distance covered.