Speed Calculator
Calculate speed, distance, or travel time from any two known values, with results shown in both mph and km/h.
Example
Drive 60 miles in 1.5 hours: speed = 60 / 1.5 = 40 mph, which equals about 64.37 km/h or 17.88 m/s.
How it works
Speed = distance / time. Rearranged, distance = speed x time and time = distance / speed. Distance is entered in miles or kilometers and time in hours; the result is converted between mph and km/h using 1 mile = 1.609344 km.
Good to know
This Speed Calculator solves any one part of the speed-distance-time relationship once you know the other two. Set the mode to Speed, Distance, or Time, pick whether your distance is in miles or kilometers, and type in the values you have. It is built for drivers planning trips, runners and cyclists checking their pace, students working through physics homework, and anyone who needs a quick rate-of-travel figure without doing the arithmetic by hand.
Reach for it whenever you want to convert "I covered X in Y" into a usable rate, or work backwards to find how far you'll get or how long a journey will take. Typical uses include estimating arrival times for a road trip, sanity-checking a treadmill or GPS pace, or confirming a calculated answer in class. Because the math is unit-aware, you can enter distance in kilometers and still read the speed off in mph.
How to read the output depends on the mode. In Speed mode the main figure is shown in your chosen unit, with parallel readouts in mph, km/h, and m/s so you can pick the system you think in. In Distance mode you get miles and kilometers side by side; in Time mode the result appears three ways: a decimal hour value, an hours-and-minutes breakdown (for example 1h 30m), and the total in minutes, which is handy for short trips.
One practical caveat: the calculator assumes a single constant average rate and that time is entered in hours, so 30 minutes must be typed as 0.5, not 30. Real journeys rarely hold one steady speed, so treat the answer as an average rather than a moment-to-moment value, and remember it does not account for stops, traffic, or acceleration.
Frequently asked questions
How do I find time from speed and distance?
Switch the mode to Time, then enter your distance and speed. The calculator divides distance by speed (time = distance / speed) and shows the result in hours, hours:minutes, and total minutes.
Why do mph and km/h both show up?
Speed is unit-independent, so the same physical speed is displayed in both units using the exact conversion 1 mile = 1.609344 km. This lets you read the result in whichever system you prefer without re-entering anything.
Is my data uploaded anywhere?
No — this calculator runs entirely in your browser. Your inputs never leave your device, and it works offline once loaded.
Is this calculator free?
Yes, completely free with no sign-up and no limits.
People also ask
What is the formula for speed, distance, and time?
Speed equals distance divided by time. The same relationship rearranges to distance = speed x time and time = distance / speed, which is exactly how the three modes of this calculator switch between solving for each value.
How do I convert mph to km/h?
Multiply miles per hour by 1.609344 to get kilometers per hour. For example, 40 mph x 1.609344 is about 64.37 km/h; this tool applies that exact conversion automatically and shows both units at once.
How do I enter 30 minutes in a speed calculator that uses hours?
Convert the minutes to a decimal fraction of an hour by dividing by 60. So 30 minutes is 0.5 hours, 15 minutes is 0.25, and 45 minutes is 0.75.
How fast is 1 meter per second in km/h?
One meter per second equals 3.6 kilometers per hour, because there are 3,600 seconds in an hour and 1,000 meters in a kilometer. To go the other way, divide a km/h figure by 3.6 to get meters per second.
What is a good average driving speed for estimating travel time?
It varies widely by road type and conditions, but many people use roughly 60 mph (about 97 km/h) for highway driving and 30 mph or less for city driving. Actual averages are lower than top speed once stops and traffic are included.
Does this speed calculator measure my live speed using GPS?
No. It is a manual math tool that computes a single average rate from values you type in; it does not read GPS, sensors, or motion. It runs entirely in your browser and stores nothing.
Why does the same speed show different numbers in mph and km/h?
They are two units describing the identical physical speed, like measuring the same distance in feet versus meters. The km/h figure is always larger than the mph figure for the same speed because a kilometer is shorter than a mile.
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