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Speed Distance Time Calculator
Solve any side of the speed, distance, and time triangle with this free speed distance time calculator. Pick what you want to find — speed, distance, or time — enter the other two values in any units, and get the answer instantly, with the working shown underneath.
The answer unit list changes to match what you are solving for.
| Speed | 60.00 km/h |
| Distance | 120.00 km |
| Time | 2.00 hours |
How it works
Speed, distance, and time are tied together by one simple relationship: how far you go depends on how fast you move and for how long. If you know any two of the three, the third is fixed, and this speed distance time calculator finds whichever one is missing. That is what makes it different from a plain speed calculator, which only works out speed from a distance and a time. Here you choose the unknown first — speed, distance, or time — and the tool rearranges the same relationship to solve for it.
Start by picking "Solve for". If you choose speed, enter the distance and the time. If you choose distance, enter the speed and the time. If you choose time, enter the distance and the speed. Every input has its own unit selector, so you can mix freely: a distance in miles with a time in minutes, or a speed in knots with a distance in kilometres. The answer unit selector then offers the units that make sense for the value you are solving for, so you always get the answer in the form you want.
Behind the scenes, the calculator converts every input into metres and seconds, does the arithmetic once, and converts the answer back into your chosen unit. That is what lets mixed units work: 60 mph is 26.82 metres per second, 120 km is 120,000 metres, and 2 hours is 7,200 seconds, so the same calculation works no matter which units you typed in. The breakdown table under the answer shows all three values together in common units, which is a quick way to sanity-check the result — if the distance and time look right but the speed looks wrong, one of the units is probably not what you meant.
The same triangle turns up everywhere: planning a road trip, checking a running pace, working out how long a delivery will take, or converting a cycling speed into the time a route will need. The key habit is keeping the units straight. A speed in miles per hour with a time in minutes gives a distance in miles only if the minutes are first turned into hours — 30 minutes is 0.5 hours, not 30. This calculator handles that conversion for you, so you can type the numbers as you think of them and trust the answer.
Worked example
A driver covers 120 km in 2 hours. How fast were they going?
Step 1: Choose "Solve for Speed" and set the answer unit to km/h.
Step 2: Enter the distance as 120 km and the time as 2 hours.
Step 3: Apply the formula: Speed = Distance ÷ Time = 120 ÷ 2 = 60 km/h.
Step 4: For the miles-per-hour figure, convert: 60 km/h × 0.621371 = 37.28 mph.
The tool shows the same result: 60 km/h, with 37.28 mph underneath. Try the triangle the other way: switch to "Solve for Distance", enter 50 mph and 3 hours, and the tool returns 150 miles — the same relationship, rearranged.
FAQ
How do I calculate speed from distance and time?
Divide the distance by the time. For example, 120 km covered in 2 hours is 120 ÷ 2 = 60 km/h. Choose Solve for speed in the calculator, enter the distance and the time with their units, and the tool does the division and converts the answer into the speed unit you picked.
How do I find the distance if I know the speed and time?
Multiply speed by time. Driving at 50 mph for 3 hours covers 50 × 3 = 150 miles. Choose Solve for distance, enter the speed and the time, and the tool returns the distance in the unit you select, such as miles or kilometres.
How do I work out how long a trip will take?
Divide the distance by the speed. A 300 km trip at 100 km/h takes 300 ÷ 100 = 3 hours. Choose Solve for time, enter the distance and the speed, and the tool gives the trip time in hours, minutes, or seconds — whichever you pick.
What is the difference between this calculator and a speed calculator?
A plain speed calculator only answers one question: how fast, given a distance and a time. This calculator solves the whole triangle, so it can find any one of the three — speed, distance, or time — from the other two. If you already know the speed and want the distance or the trip time, this is the tool to use.
Can I mix units, like miles with km/h?
Yes. Every input has its own unit selector, so you can enter a distance in miles, a speed in km/h, and ask for the time in minutes. The calculator converts everything to metres and seconds behind the scenes, works out the answer, and converts it back into the unit you chose for the result.