Solve for speed, distance, or time using speed = distance ÷ time, with results in km/h, m/s, and mph.
Enter the two known values and click Calculate
This free speed calculator solves for speed, distance, or time using the classic physics formula speed = distance ÷ time. Choose which value you're missing, enter the two you know, and get your result instantly — with speed shown in km/h, m/s, and mph all at once.
Enter distance in kilometers and time in hours to solve for average speed. Rearranging the same formula, the calculator can instead solve for distance (speed × time) when you know speed and time, or for time (distance ÷ speed) when you know distance and speed. Every speed result is automatically converted into km/h, m/s, and mph so you can use whichever unit you need.
Physics students working through distance-speed-time problems, runners and cyclists estimating average pace for a route, and anyone planning a trip who wants a quick travel-time or arrival estimate. It calculates average speed over a distance and time, not instantaneous speedometer readings.
The three rearrangements of the speed formula this calculator uses
Speed is fundamentally a rate — how much distance is covered per unit of time — which is why dividing distance by time gives speed directly.
Simple algebra turns the same relationship into a distance formula (multiply) or a time formula (divide), covering all three unknowns.
This calculator produces average speed over the whole distance and time entered — real-world speed usually varies throughout a trip.
From choosing what to solve for to reading your result
Select Speed, Distance, or Time depending on which value you're missing.
Fill in distance (km) and time (hours), or speed and one of the others, depending on the mode.
See the missing value, with speed results shown in km/h, m/s, and mph.
Solving for speed, then rearranging to solve for time
Where solving for speed, distance, or time comes up
Solve speed, distance, and time word problems and verify your answer.
Estimate travel time or average speed needed to arrive by a certain time.
Find average speed for a route based on tracked distance and time.
Estimate flight or shipping speed and duration for planning purposes.
Calculate the average speed of an object measured moving over a set distance and time.
What this speed calculator does well, and where it has boundaries
Get an accurate speed, distance, or time result
Summary: This speed calculator solves for speed, distance, or time using speed = distance ÷ time, with results shown in km/h, m/s, and mph — free, instant, and useful for physics problems and trip planning alike. Pair it with NeftCal's Pace Calculator or Mass Calculator for related physics work.
Common questions about calculating speed
Standards references to complement this calculator
Other measurement and travel tools