Math
Speed, distance, time calculator
Enter any two of speed, distance, and time — the calculator solves for the third. Pick units independently (km/h, mph, m/s, knots for speed; km, mi, m for distance).
Formula
The relation v = d / t is one of the most-used formulas in everyday math: trip planning, run pace, drive time, flight ETA, average speed back-calculation. This calculator handles the three solve directions and mixes units freely — input in mph, output in km/h, etc.
Units are converted via base SI (km/h for speed, km for distance) internally. Time is always in hours; the result also shows hours-minutes-seconds form for readability.
This is constant-speed math — it doesn't account for acceleration, traffic stops, headwind, or terrain. For real trip planning, multiply 'pure driving time' by 1.1–1.3 for buffer.
Examples
- 01120 km in 2 hours→ Speed = 60 km/h
- 0260 km/h for 2.5 hours→ Distance = 150 km
- 03200 km at 80 km/h→ Time = 2.5 h = 2h 30m 00s
- 04Marathon 42.195 km at 12 km/h→ Time ≈ 3.52 h ≈ 3h 30m 58s
FAQ
- No. Velocity is a vector (speed + direction); speed is a scalar (magnitude only). For straight-line travel they're equivalent in magnitude, which is what this calculator computes. For curved or 2D motion, you need vector decomposition.
References
Note: Results are accurate to floating-point precision (~15 significant digits) for the standard formula shown above. See our terms of use for general usage information.