Speed Calculator
Speed, distance, and time are related by three simple formulas: speed = distance ÷ time, distance = speed × time, and time = distance ÷ speed. Enter any two values and this calculator instantly derives the third across multiple unit systems simultaneously, km/h, mph, m/s, knots, feet per second, and pace units (min/km, min/mile). Unit conversion is handled internally, so you can freely mix metric and imperial inputs. In Australia, road speed limits are posted in km/h (50 in suburban streets, 60–80 on arterials, 100–110 on highways and motorways), while weather wind speeds are in km/h, aircraft speeds in knots, and physics calculations in m/s. Converting between these is a regular need for engineers, meteorologists, athletes, and anyone comparing performance data across measurement systems. For running-specific pace calculations with split tables, use the running pace calculator on this site.
Frequently Asked Questions
How is speed calculated?
Speed is calculated as Distance divided by Time (Speed = Distance ÷ Time). Enter any two of the three values - distance, time, or speed - and the calculator automatically derives the third. It supports multiple units including km/h, mph, m/s, knots, feet per second, and reverse pace units like minutes per kilometre. The calculator handles all unit conversions internally, so you can freely mix units - for example, entering distance in miles and time in hours will give you a result in km/h. For pace-specific split times for running, the dedicated running pace calculator is more specialised.
What's the difference between km/h and m/s?
Kilometres per hour (km/h) and metres per second (m/s) both measure speed but use different time and distance units. The conversion is fixed: 1 m/s equals exactly 3.6 km/h, and 1 km/h equals approximately 0.278 m/s. A speed of 10 m/s (typical cycling pace) equals 36 km/h, while a highway speed of 100 km/h is about 27.8 m/s. In Australia, road speed limits are posted in km/h, while scientific, physics, and many international sporting contexts use m/s for consistency. Knowing how to convert between them lets you compare car performance data, athletic results, and weather wind speeds regardless of which unit system they are reported in.
What is a good average running speed?
Average running speed varies widely based on fitness level, age, distance, terrain, and weather. For recreational joggers, 8-10 km/h (about 5-6 min/km) is typical. Regular runners who train consistently often average 11-13 km/h (4.5-5 min/km). Well-trained runners may sustain 14-17 km/h (3.5-4 min/km) over longer distances. Elite marathon runners maintain around 20-21 km/h (roughly 3 min/km pace) over the full 42.2km. In Australia, Parkrun events (free weekly 5km runs held nationwide every Saturday morning) provide useful benchmarks: the median finish time is around 27-28 minutes for men (~10-11 km/h) and 30-32 minutes for women (~9-10 km/h). Trail running, hills, heat, humidity, and wind all significantly reduce average speed regardless of fitness level.
Why do I get different speeds on a treadmill vs outdoor running?
Treadmills account for no wind resistance, so your effort at a set treadmill pace is equivalent to a slightly faster outdoor pace. A general rule is adding 1-2 km/h to your treadmill speed to match outdoor effort. This varies with treadmill brand and calibration - some newer treadmills auto-adjust for the lack of air resistance.
How do I convert mph to km/h?
Multiply mph by 1.60934 to get km/h. For example, 60 mph = 96.56 km/h, 70 mph = 112.65 km/h. Australia's road speed limits are in km/h, ranging from 50 km/h in suburban streets to 100-110 km/h on highways, so converting from overseas driving speeds is a common use of this calculator.