Formula
Average speed = distance ÷ elapsed time. mph = miles ÷ hours. km/h = kilometres ÷ hours, using 1 mile = 1.609344 kilometres. m/s = metres ÷ seconds. Pace = elapsed time ÷ distance.
Speed Calculator
Calculate speed from distance and time, with miles per hour, kilometres per hour, metres per second and pace kept visible for travel, sport, classroom and job records.
Worked example
For 10 miles in 45 minutes, elapsed hours = 45 ÷ 60 = 0.75 h. Average speed = 10 ÷ 0.75 = 13.33 mph. Distance in kilometres = 10 × 1.609344 = 16.09344 km, so speed = 16.09344 ÷ 0.75 = 21.46 km/h.
Professional note
Master’s Tip: label whether the distance came from a measured course, vehicle odometer, GPS trace or treadmill. The formula is simple, but the printed report is more useful when the measurement source and any stop-time assumptions are written beside the average speed.
Regional and unit assumptions
Standard or basis: statute miles, exact international mile-to-kilometre conversion and elapsed clock time. This is planning and classroom arithmetic, not a certified speedometer, race timing, transport compliance or enforcement measurement.
Assumptions and limitations
- Distance is entered in statute miles and converted to kilometres using 1 mile = 1.609344 km.
- Elapsed time is hours + minutes + seconds; if total time is zero, speed is not defined.
- The result is average speed across the whole distance, not instant speed at one point.
- Traffic, stops, GPS drift, elevation change, route detours, treadmill calibration and legal speed measurement rules are not included.
Methodology & Accuracy
How this calculator is checked
CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.
Formula used
Average speed = distance ÷ elapsed time. mph = miles ÷ hours. km/h = kilometres ÷ hours, using 1 mile = 1.609344 kilometres. m/s = metres ÷ seconds. Pace = elapsed time ÷ distance.
Standard or basis
Standard or basis: statute miles, exact international mile-to-kilometre conversion and elapsed clock time. This is planning and classroom arithmetic, not a certified speedometer, race timing, transport compliance or enforcement measurement.
Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.Master's Tip
Master’s Tip: label whether the distance came from a measured course, vehicle odometer, GPS trace or treadmill. The formula is simple, but the printed report is more useful when the measurement source and any stop-time assumptions are written beside the average speed.
Related calculators
Questions
How do you calculate average speed?
Divide distance by elapsed time. For miles per hour, divide miles by hours. If the time includes minutes and seconds, convert the whole elapsed time to decimal hours first.
What is the formula for mph?
mph = miles ÷ hours. For example, 10 miles in 0.75 hours is 10 ÷ 0.75 = 13.33 mph.
Does this calculate pace too?
Yes. The page also divides elapsed time by distance to show pace per mile and pace per kilometre, which is useful for running, walking and trip notes.
Is this instant speed or average speed?
It is average speed across the full distance and elapsed time. Instant speed can vary during the trip or activity.
Can I use this as proof of a legal speed?
No. It is transparent arithmetic for planning, study and personal records. Legal or certified speed measurement requires approved equipment, procedure and jurisdiction-specific rules.
Calculation note
Speed is distance compared with time. The same calculation helps travellers estimate arrival times, runners compare pace, teachers explain rates and tradespeople record equipment or site movement assumptions.
Average speed is a rate, not a moment
A trip can include faster sections, slower sections and stops. Average speed compresses the whole journey into one rate by dividing total distance by total elapsed time.
Unit choice changes the label, not the idea
Miles per hour, kilometres per hour and metres per second all express distance per unit of time. The conversion must happen before comparing results, especially when vehicle, sport and classroom records use different unit systems.
Pace is the inverse view
Runners and walkers often prefer pace instead of speed. Pace asks how much time is needed for one mile or one kilometre, so it is calculated by dividing elapsed time by distance.
Sources and further readingNIST Handbook 44 Appendix C: General Tables of Units of Measurement