Velocity Calculator

The formula is v = Δx / Δt: velocity equals displacement divided by time interval. Example: 100 m ÷ 9.58 s = 10.4384 m/s = 37.5783 km/h.

Speed is a scalar: |Δx| / Δt, always positive. Velocity is a 1D vector: Δx / Δt, its sign indicating direction. Example: running 400 m out and back (displacement 0) in 60 s → average velocity 0 m/s, while speed is 6.6667 m/s.

Use Δx = v × t. Example: 25 m/s × 120 s = 3,000 m (3 km).

Use t = Δx / v. Example: marathon 42,195 m ÷ 5.5 m/s = 7,671.82 s = 2 hr 7 min 51.82 s.

Use v_avg = ΣΔx / ΣΔt: sum all displacements, divide by the sum of all times. Example segments (10, 2), (30, 4), (−5, 3): ΣΔx = 35 m, ΣΔt = 9 s → 3.8889 m/s. Note: opposite-direction segments (negative Δx) reduce total displacement.

Divide by 3.6: 100 ÷ 3.6 = 27.7778 m/s. Conversely 60 mph = 60 × 0.44704 × 3.6 = 96.56 km/h.

1 knot = 1 nautical mile per hour = 1,852 m / 3,600 s = 0.5144 m/s. This unit is common in marine navigation and aviation.

c = 299,792,458 m/s (exact SI definition). 10.4384 ÷ 299,792,458 = 3.4819×10⁻⁸ c — practically zero for everyday speeds. The c fraction in this tool is for reference only, not relativistic physics.

This tool is specifically for constant-velocity motion. If there is acceleration (v₀, a, t), use the SUVAT solver at /tools/suvat/, which solves the 5 accelerated-motion equations.

For special cases, use the domain-specific tools: free-fall velocity, pipe velocity / water velocity (pipe flow), angular velocity (circular motion), escape velocity / orbital velocity (gravity), muzzle velocity (ballistics), resultant velocity (2-vector resultant), or velocity addition (Einstein relativistic addition). This tool is only for generic linear motion.