Work out average speed, distance, or travel time. Enter any two of the three values — each with its own unit — and the calculator finds the third using speed = distance ÷ time.
The speed calculator works out the average speed of a moving object from the distance it travels and the time it takes — and it runs in every direction. Enter any two of distance, time, and speed, and the calculator instantly finds the third. Each field has its own unit, so you can mix and match kilometers with hours, miles with minutes, or meters with seconds, and read the answer in km/h, mph, m/s, ft/s, or knots. Whether you are planning a road trip, checking a runner's pace, or solving a physics problem, this tool does the conversion and the arithmetic for you.
Speed is one of the most familiar quantities in everyday life. It tells you how quickly something is moving — how much ground it covers in a given amount of time. Because distance, time, and speed are locked together by a single formula, knowing any two of them is always enough to find the missing one, which is exactly what makes this calculator so handy.
Speed is the rate at which an object covers distance. In plain terms, it answers the question, "How far does this thing travel in a given amount of time?" A car moving at 100 kilometers per hour covers 100 kilometers every hour; a runner at 5 meters per second covers 5 meters every second. Speed always combines a distance unit with a time unit — miles per hour, meters per second, and so on — which is why the units matter as much as the number.
The calculator computes average speed: the total distance divided by the total time. It does not track how the speed varied along the way — whether the object sped up, slowed down, or stopped — only the overall rate for the whole journey. For a trip that covers 100 km in 2 hours, the average speed is 50 km/h, even if the actual speed ranged from 0 at a traffic light to 120 on the highway.
The relationship between speed, distance, and time is captured in one simple formula:
average speed = total distance ÷ total time
This single equation can be rearranged to solve for whichever value you are missing:
These three forms are the same relationship viewed from different angles. A popular memory aid is the "speed triangle," with distance on top and speed and time on the bottom: cover the quantity you want, and the position of the other two shows you whether to multiply or divide. The calculator applies whichever rearrangement fits the two values you enter.
Suppose you drive 100 kilometers and the trip takes 2 hours. Enter distance = 100 km and time = 2 hours, leave speed blank, and the calculator returns:
speed = 100 km ÷ 2 h = 50 km/h
Now suppose instead you know you can drive at 50 km/h and want to know how long 100 km will take. Enter speed = 50 km/h and distance = 100 km, and the calculator returns a time of 2 hours. Or enter speed and time to find the distance covered. Whichever two numbers you have, the third follows immediately.
Speed can be expressed in many units, and this calculator supports the most common ones:
Because the calculator converts everything to a common basis internally, you never have to convert by hand: enter your distance and time in whatever units you have, and pick the speed unit you want the answer in.
It helps to know a few of the key conversions. One kilometer per hour equals about 0.621 miles per hour, so a 100 km/h highway speed is roughly 62 mph. To convert meters per second to kilometers per hour, multiply by 3.6 — so 10 m/s is 36 km/h. One knot is about 1.15 mph or 1.852 km/h. And one mile per hour is roughly 1.467 feet per second. These conversions come up constantly when comparing speeds quoted in different systems, and the calculator handles all of them automatically, but keeping the rough factors in mind is useful for quick sanity checks.
It is important to understand what "average speed" does and does not tell you. Average speed is the total distance divided by the total time for a whole journey — a single number summarizing the trip. Instantaneous speed is how fast you are going at one particular moment, the number your speedometer shows. The two can be very different: a commute might have an average speed of just 30 km/h because of traffic and stops, even though you hit 100 km/h on the open road. This calculator computes average speed, which is the right measure for planning journeys and comparing overall performance, but remember it smooths over all the variation in between.
In everyday language "speed" and "velocity" are used interchangeably, but in physics they mean different things. Speed is a scalar — it has only magnitude, telling you how fast something moves. Velocity is a vector — it has both magnitude and direction, telling you how fast and which way. A car going around a circular track at a constant 60 km/h has a constant speed but a continuously changing velocity, because its direction keeps changing. Acceleration, in turn, is the rate at which velocity changes over time. This calculator deals with speed — the everyday, direction-free measure — which is what you need for the vast majority of practical distance-and-time problems.
Because it accepts any two of the three, you can use it as a speed calculator, a distance calculator, or a travel-time calculator, all in one.
Speed calculations are at the heart of competitive sport. When a sprinter runs 100 meters in 9.8 seconds, their average speed is 100 ÷ 9.8 = about 10.2 m/s, or roughly 36.7 km/h — and top sprinters reach an instantaneous peak well above that in the middle of the race. A swimmer, a cyclist, and a speed skater are all ranked by the same simple relationship between the distance of their event and the time they record. Because the events are fixed distances, dividing by the finishing time is exactly how average speed and pace are compared across athletes. The same math lets you turn your own workout — a 5 km run in 25 minutes, say — into an average speed of 12 km/h, so you can track your progress over time or compare it against a target. Enter your distance and time above to see where you land.
It helps to have a feel for how fast different speeds actually are. Here are some everyday reference points:
Seeing where a calculated speed falls among these benchmarks is a quick way to sanity-check a result. If your math says a car is doing 500 km/h, you have almost certainly mixed up a unit somewhere — and the calculator's unit dropdowns are designed to prevent exactly that kind of slip.
The most common mistake in any speed, distance, or time problem is not the arithmetic — it is the units. Dividing a distance in miles by a time in minutes gives a number, but not miles per hour; it gives miles per minute, which is sixty times larger. Mixing metric and imperial units is just as easy to do by accident. This is why the calculator attaches a unit to every field and converts everything to a common internal basis before doing the math. You are free to enter a distance in kilometers, a time in minutes, and read the speed in miles per hour, and the conversions are handled correctly behind the scenes.
The same care applies when you interpret the answer. A result of "2 hours" for a trip means two hours of actual travel at the given average speed; if you plan to stop for lunch or hit traffic, the real journey will take longer. For that reason, when you are planning arrival times it is often wise to use a slightly lower average speed than the road's limit, to build in a realistic allowance for stops, congestion, and slowing down through towns. The calculator gives you the exact mathematical answer; applying a little judgment on top turns it into a dependable estimate.
Divide the total distance by the total time: average speed = distance ÷ time. For example, 100 kilometers in 2 hours gives an average speed of 50 km/h.
Multiply the speed by the time: distance = speed × time. At 50 km/h for 2 hours, you cover 50 × 2 = 100 km. Enter the speed and time in this calculator and leave distance blank.
Divide the distance by the speed: time = distance ÷ speed. Covering 100 km at 50 km/h takes 100 ÷ 50 = 2 hours. Enter the distance and speed and leave time blank.
Multiply by 3.6. So 10 meters per second equals 36 kilometers per hour. To go the other way, from km/h to m/s, divide by 3.6.
A knot is one nautical mile per hour, used in aviation and at sea. One knot equals about 1.852 km/h or 1.15 mph. This calculator includes knots as a speed unit.
Speed is how fast something moves and has only a magnitude. Velocity also includes direction. For most everyday distance-and-time problems, speed is the quantity you want, and it is what this calculator computes.
This Speed Calculator is provided for educational and general informational purposes. It computes average speed, distance, or time using the standard formula and unit conversions. For navigation, safety-critical, or professional applications, verify results with the appropriate specialized tools.