t\). Mix units freely:
kilometres, miles, metres, nautical miles, seconds, minutes or hours. The tool also computes equivalent speeds in m/s, km/h, mph and knots, and includes an average speed calculator for multi-leg trips. Solve for speed, distance or time What do you want to calculate? Speed (v) Distance (d) Time (t) Distance (d) km m mile nautical mile Examples: 5 km, 2000 m, 3 miles, 2.5 nautical miles. Time (t) hour minute second Examples: 2 h, 45 min, 30 s. You can use decimals (e.g. 1.5 h). Speed (v) km/h m/s mph knots Choose the units of the speed you know. Preferred speed unit for the main result km/h (kilometres per hour) m/s (metres per second) mph (miles per hour) kn (knots, nautical miles per hour) The result table will show all units; this setting controls the highlighted one. Calculate Clear Use dot or comma as decimal separator. Empty fields are treated as unknowns. Result Equivalent speeds Unit Value Average speed for multi-leg trips Average speed over a whole journey is defined as
\( \text{average speed} = \dfrac{\text{total distance}}{\text{total time}} \),
not the simple average of segment speeds. Use this section to combine several legs. Trip legs + Add leg Clear legs Leg Distance Unit Time Unit Compute average speed km/h (kilometres per hour) m/s (metres per second) mph (miles per hour) kn (knots) Tip: you can mix units across legs (e.g. some in km, some in miles). The calculator converts
everything internally and reports the global average speed. Speed–distance–time relationship The core relationship between speed, distance and time is \( v = \dfrac{d}{t}, \quad d = v \cdot t, \quad t = \dfrac{d}{v} \) where \(v\) is speed, \(d\) is distance, and \(t\) is time. As long as you know any two of the three quantities, you can compute the third. The only strict
requirement is to keep units consistent – for example, kilometres with hours or metres with seconds. Speed–distance–time triangle A popular memory aid is the speed–distance–time triangle . Draw a triangle, put
distance \(d\) at the top, and speed \(v\) and time \(t\) at the bottom corners: d v t Cover the quantity you want: if you cover \(v\), the remaining layout shows \(d
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