Formulas & Conversions
Time
T = Distance ÷ Speed
Speed
S = Distance ÷ Time
Distance
D = Speed × Time
km/h → m/s
× (5/18) | m/s → km/h: × (18/5)
How to Use
1
Select Unknown
Pick the tab for what you want to find — Time, Speed or Distance.
2
Enter Two Values
Fill in the two known values and select their units from the dropdowns.
3
Get Answer
Click Calculate for an instant result. Use Unit Converter for km/h ↔ m/s.
Frequently Asked Questions
Multiply by 5/18. Example: 72 km/h = 72 × 5/18 = 20 m/s. To convert m/s to km/h, multiply by 18/5.
Speed = Distance ÷ Time = 200 ÷ 10 = 20 m/s = 20 × 18/5 = 72 km/h.
Average Speed = 2ab ÷ (a+b), where a and b are the two speeds. Example: going at 40 km/h and returning at 60 km/h → Average = 2×40×60 ÷ (40+60) = 4800 ÷ 100 = 48 km/h.