Need to find speed, distance, or time? Just enter any two values and our free speed calculator gives you the third instantly. Convert between mph, km/h, m/s, knots, and more. Perfect for trip planning, physics homework, running pace, and everyday calculations.
| m/s | km/h | mph | kn | ft/s | |
|---|---|---|---|---|---|
| 1 meter/second [m/s] | 1 | 3.6 | 2.236928 | 1.943844 | 3.280840 |
| 1 kilometer/hour [km/h] | 0.277778 | 1 | 0.621369 | 0.539957 | 0.911344 |
| 1 mile/hour [mph] | 0.44704 | 1.60935 | 1 | 0.868979 | 1.466672 |
| 1 knot [kn] | 0.514444 | 1.852 | 1.150775 | 1 | 1.687810 |
| 1 foot/second [ft/s] | 0.3048 | 1.09728 | 0.681816 | 0.592484 | 1 |
Quick reference for converting between common speed units
| m/s | km/h | mph | |
|---|---|---|---|
| Average walking speed | 1.4 | 5 | 3.1 |
| Peak human running speed | 12.42 | 44.7 | 27.8 |
| Peak cheetah running speed | 33.53 | 120.7 | 75 |
| Average orbital speed of the Earth | 29,783 | 107,218 | 66,623 |
| Average orbital speed of the Sun | 251,000 | 904,000 | 561,000 |
| Speed of sound in air (sea level, 20°C) | 343 | 1,235 | 768 |
| Speed of light in vacuum | 299,792,458 | 1,079,252,848 | 670,616,629 |
Reference speeds from walking pace to the speed of light
Speed is just how fast something moves. It tells you the distance something covers in a certain amount of time.
Think about it like this: if you're driving and your speedometer says 60 mph, that means you'll travel 60 miles in one hour (if you keep that speed).
Speed = Distance ÷ Time
But here's where it gets interesting. You can rearrange this formula to find any of the three values:
Distance
= Speed × Time
Time
= Distance ÷ Speed
Speed
= Distance ÷ Time
That's it. That's the whole thing. But let's talk about why people get confused.
This is a big one. A lot of people use these words like they mean the same thing. They don't.
🏃 Speed
Just how fast. Doesn't care about direction. "60 mph" is speed.
🧭 Velocity
Speed with a direction. "60 mph north" is velocity.
For most everyday stuff — driving, running, biking — you only care about speed. Velocity matters more in physics and engineering.
Using our calculator is dead simple. Here's how:
Pick what you want to find. Are you trying to find speed, distance, or time? Choose that option first.
Enter your numbers. Put in the two values you know. For example, if you want to find speed, enter the distance and time.
Choose your units. This is where most mistakes happen. Make sure your units match. If distance is in miles and time is in hours, your speed will be in mph.
Hit calculate. That's it. The calculator does the rest.
NY to DC = 225 miles. Want to arrive in 4 hours. Speed = 225 ÷ 4 = 56.25 mph. Doable on the highway, but doesn't include traffic or bathroom breaks.
5K = 3.1 miles. Goal: 25 minutes. Convert to hours: 25 ÷ 60 = 0.417 hrs. Speed = 3.1 ÷ 0.417 = 7.44 mph. That's about an 8-minute mile pace — solid for a beginner.
You bike at 12 mph. Office is 6 miles away. Time = 6 ÷ 12 = 0.5 hours = 30 minutes. Easy — unless there's a hill, then your average speed might drop.
Mixing Up Units
This is #1. If your distance is in miles and your time is in minutes, you can't just divide. Convert minutes to hours first. Example: 30 minutes = 0.5 hours.
Forgetting to Convert Time
People put in "30" for minutes and get a weird answer. Remember: the formula works when time is in hours (for mph or km/h). If using minutes, convert first.
Confusing Average Speed with Instantaneous Speed
Your speedometer shows instantaneous speed — how fast right now. Average speed = total distance ÷ total time. They're different. Drive 60 mph for an hour, then sit in traffic for an hour at 0 mph = average speed of 30 mph.
Think about it like sharing pizza. If you have 8 slices and 4 people, each person gets 2 slices (8 ÷ 4 = 2).
Speed works the same way. If you travel 100 miles in 2 hours, each hour you covered 50 miles (100 ÷ 2 = 50 mph).
The formula is just saying: "Spread the distance evenly across each unit of time."
The word "speed" comes from an old English word "sped" which meant prosperity or success. Back then, being fast meant you were successful.
And here's something cool — the speed formula (distance = rate × time) was first written down by a Persian mathematician named Al-Khwarizmi around 820 AD. He's the same guy who gave us algebra. So every time you calculate speed, you're using math that's over 1,200 years old.
Here's a trick I learned from a physics teacher: if you're calculating average speed for a trip with multiple segments, don't just average the speeds. You need the total distance divided by total time.
Example: You drive 60 mph for 1 hour (60 miles), then 30 mph for 1 hour (30 miles). Total distance = 90 miles. Total time = 2 hours. Average speed = 45 mph. That happens to match the average of 60 and 30 because the times were equal — but if times are different, always use total distance ÷ total time.
Sometimes the calculator gives you a number that doesn't make sense. Here's what to check:
Did you use the right units? (miles vs km, hours vs minutes)
Did you enter the numbers correctly? (check for typos)
Is the answer too small or too big? (a car going 0.5 mph is basically stopped)
Did you pick the right calculation? (speed vs distance vs time)
If something seems off, double-check your inputs. 99% of the time, it's a unit problem.
Students — for physics and math homework
Runners and cyclists — to figure out pace and training times
Drivers — for trip planning and fuel efficiency
Engineers — for designing vehicles and systems
Scientists — for experiments and data analysis
Teachers — to create examples for their classes
No matter who you are, if you need to figure out speed, distance, or time, this calculator has you covered.
Average speed is total distance divided by total time. So if you drove 150 miles in 3 hours, your average speed is 150 ÷ 3 = 50 mph. It doesn't matter if you went faster or slower at different points — average speed just looks at the whole trip.
Speed is just how fast something is moving. Velocity is speed with a direction. So "50 mph" is speed. "50 mph north" is velocity. For most everyday situations, you only need speed. Velocity matters more in physics and engineering.
Multiply mph by 1.609 to get km/h. So 60 mph × 1.609 = 96.54 km/h. To go the other way, divide km/h by 1.609. Our calculator does this automatically if you pick the right units.
You probably mixed up units. If you put distance in miles and time in minutes, you'll get a weird number. Convert minutes to hours first (divide by 60). Or use our calculator which handles unit conversions for you.
Multiply speed by time. If you're going 55 mph for 2 hours, distance = 55 × 2 = 110 miles. Just make sure your units match — if speed is in mph, time should be in hours.
Divide distance by speed. If you need to travel 200 miles at 50 mph, time = 200 ÷ 50 = 4 hours. This works for any units as long as they're consistent.
The basic formula is v = d/t, where v is speed, d is distance, and t is time. You can rearrange it to find any value: d = v × t or t = d ÷ v. That's all you need for most problems.
No. Instantaneous speed is how fast you're going at one exact moment (like your speedometer reading). Average speed is total distance divided by total time. They can be very different — like when you're speeding up or slowing down.
Pace is usually minutes per mile or minutes per kilometer. Divide your time (in minutes) by distance. If you run 3 miles in 24 minutes, your pace is 24 ÷ 3 = 8 minutes per mile. Our speed calculator can help with this.
The speed of light is the fastest anything can go — about 186,282 miles per second or 299,792 kilometers per second. Nothing with mass can reach this speed. For everyday stuff, you'll never need to worry about this limit.
Include your stop time in the total time. If you drive 300 miles in 5 hours but stopped for 30 minutes, your total time is 5.5 hours. Average speed = 300 ÷ 5.5 = 54.5 mph. This gives you a more realistic estimate.
Speed is how fast you're going. Acceleration is how quickly your speed changes. If you go from 0 to 60 mph in 10 seconds, your acceleration is 6 mph per second. Speed tells you where you are. Acceleration tells you how you got there.
Here are some other calculators you might find useful: