Find speed, distance, or travel time

You pick the unknown. The other two fields are read; the third is ignored. Time is a duration in hours (1.25 = 1 h 15), not a clock time. No breaks, hills or speed limits enter the model: it is average speed over the whole trip.

v = d / t

d = v × t

t = d / v

This is the definition of average speed, not a GPS. Door-to-door 120 km in 1 h 30 includes lights; the speed is lower than cruising speed. Miles per hour are fine if both distance and speed are imperial; the engine does not convert km ↔ mi. For running pace (min/km), the dedicated tool is clearer.

I want

The unknown. Fill the other two fields.

Distance

Whole trip, km or miles matching the speed unit.

Time

Duration in decimal hours. 0.75 = 45 minutes.

Speed

Average speed, not a posted limit.

Assumptions

• Constant average speed over the trip.
• Matching units for distance and speed.
• Time is a duration, not a clock.

Limits

• No breaks, tolls or hills.
• No automatic km ↔ mi conversion.
• No min/km pace (see running pace).

80 km/h average on a motorway often means 110 while cruising plus slowdowns. Use it to plan an arrival, not to argue a ticket. For running, invert: min/km = 60 / (km/h).

• Typing 1:30 in the time field.

  Enter 1.5. The field is not a clock.

• Mixing km and mph.

  One pair: km with km/h, or mi with mph.

• Dividing by a time of 0.

  Without a duration, speed is undefined.

• Speed converterEvery speed routes through the metre per second. 1 km/h is exactly 1/3.6 m/s, and a knot is one nautical mile (1,852 m) per hour, not a statute mile.
• Running pacePace is total time divided by distance. Average speed is the inverse. No calories are estimated: ACSM METs are not applied here.
• Length converterEvery value goes through the meter, then to the target unit. The inch is 25.4 mm exactly since the 1959 agreement, as in the NIST SI conversion factors.
• ExponentEvaluate aᵇ. Integers, decimals, negative exponents (reciprocals), and 1/2 (square root, base ≥ 0) are possible, within the reals and floating-point limits.
• FractionsTwo integer fractions and an operation. The engine uses a common denominator or cross-products, then reduces by the GCF so the answer is in lowest terms.
• GCF (GCD)Enter at least two integers. The result is the largest positive integer that divides all of them — the same GCF used to reduce a fraction or a ratio.

Written by Rédaction HexaCalc (editorial team). Content last updated: August 25, 2026. No third-party medical or financial review is claimed.

This calculation uses a standard mathematical identity. See also the methodology.