Speed Distance Time Calculator
Speed is distance divided by time, so distance is speed times time, and time is distance divided by speed. At 40 mph a 15-mile drive takes 15 ÷ 40 = 0.375 hours, which is 22 minutes 30 seconds (see it worked out).
Fill in any two, get the third
Leave blank the one you want to find. The answer updates as you type.
Check your input
The trip, mark by mark
Same speed, another trip
Keep the speed above and change the distance or the time.
How to Use This Calculator
-
Fill in two values
Type the two things you know, for example the distance and the speed. Pick the units beside each box. Time goes in as hours, minutes and seconds.
-
Read the third
The empty value is worked out and marked as the answer. Travel times are shown in hours and minutes, so there is no decimal to convert.
-
Try another trip
Below the answer, type a new distance or time to see what it means at the same speed, and follow the trip on the time marks.
How to calculate speed, distance and time
If you know any two of speed, distance and time, you can work out the third with one of these formulas:
Many students remember these with the formula triangle: D on top, S and T side by side underneath. Cover the one you want and the other two show you what to do. Cover D and you see S × T. Cover S and you see D over T, which means divide.
Before you divide or multiply, make sure the units match. If the speed is in miles per hour, the distance must be in miles and the time in hours. If the speed is in meters per second, use meters and seconds. A shopper who pushes a cart 0.5 km in 1.5 hours moves at 0.5 ÷ 1.5 = 0.33 km/h. The same walk is 500 m in 5,400 seconds, or 0.093 m/s.
How long does it take to drive?
To find a travel time, divide the distance by the speed. The answer comes out in hours, usually with a decimal. Multiply the decimal part by 60 to get minutes. At 40 mph, 15 miles take 15 ÷ 40 = 0.375 hours, and 0.375 × 60 = 22.5 minutes, which is 22 minutes 30 seconds.
The table below gives driving times at steady speeds, rounded to the nearest minute. Real trips take longer because of stops, traffic and slower stretches.
| Distance | 30 mph | 40 mph | 50 mph | 60 mph | 70 mph |
|---|---|---|---|---|---|
| 1 mi | 2 min | 2 min | 1 min | 1 min | 1 min |
| 2 mi | 4 min | 3 min | 2 min | 2 min | 2 min |
| 5 mi | 10 min | 8 min | 6 min | 5 min | 4 min |
| 10 mi | 20 min | 15 min | 12 min | 10 min | 9 min |
| 15 mi | 30 min | 23 min | 18 min | 15 min | 13 min |
| 20 mi | 40 min | 30 min | 24 min | 20 min | 17 min |
| 30 mi | 1 h | 45 min | 36 min | 30 min | 26 min |
| 50 mi | 1 h 40 min | 1 h 15 min | 1 h | 50 min | 43 min |
| 100 mi | 3 h 20 min | 2 h 30 min | 2 h | 1 h 40 min | 1 h 26 min |
| 200 mi | 6 h 40 min | 5 h | 4 h | 3 h 20 min | 2 h 51 min |
How to calculate miles per hour
Miles per hour is the number of miles divided by the number of hours. The only step that needs care is writing the time in hours. Divide minutes by 60 first: 18 minutes is 0.3 hours, so 12 miles in 18 minutes is 12 ÷ 0.3 = 40 mph. A marathon of 26.2 miles finished in 3 hours 30 minutes, which is 3.5 hours, works out to 26.2 ÷ 3.5 = 7.49 mph.
Same speed, different distance
A common type of word problem gives you one trip and asks about another at the same rate. "Grayson drove 413 miles in 7 hours. If he continued at the same rate, how long would it take to travel 531 miles?" Solve it in two steps. First find the speed from the trip you know: 413 ÷ 7 = 59 mph. Then use that speed for the new distance: 531 ÷ 59 = 9 hours.
You can also set it up as a proportion, 413/7 = 531/t, and solve for t. Either way the answer is 9 hours. In the calculator, enter the first trip, then type the new distance in the "same speed, another trip" line under the answer.
How far you travel in one second
In the second it takes to glance at a phone, a car at 60 mph covers 88 feet. To turn mph into feet per second, multiply by 5,280 and divide by 3,600, or simply multiply by about 1.47. For meters per second, multiply mph by 0.447.
| Speed | Feet per second | Meters per second |
|---|---|---|
| 20 mph | 29.3 ft | 8.9 m |
| 30 mph | 44 ft | 13.4 m |
| 40 mph | 58.7 ft | 17.9 m |
| 50 mph | 73.3 ft | 22.4 m |
| 60 mph | 88 ft | 26.8 m |
| 70 mph | 102.7 ft | 31.3 m |
| 80 mph | 117.3 ft | 35.8 m |
Values are rounded to one decimal place. At 35 mph, three seconds of not looking at the road means about 154 feet traveled, roughly the length of half a football field.
Converting speed units
The calculator converts units for you, but these factors are worth knowing:
- km/h to m/s: divide by 3.6. 90 km/h is 25 m/s.
- m/s to km/h: multiply by 3.6.
- mph to km/h: multiply by 1.609. 60 mph is about 96.6 km/h.
- knots to mph: multiply by 1.151. A knot is one nautical mile, 1,852 meters, per hour.
A train that covers 350,000 meters at 25 m/s needs 350,000 ÷ 25 = 14,000 seconds. Divided by 3,600, that is 3.89 hours, or 3 hours 53 minutes 20 seconds. For conversions without a trip, use the speed converter.
Average speed
Average speed is the total distance divided by the total time. To get it for a whole trip, enter the full distance and the full time, with or without stops depending on what you want to measure. A common mistake is to average the speeds of the parts. If you drive 30 miles at 60 mph and then 30 miles at 30 mph, the second half takes twice as long as the first. The trip is 60 miles in 1.5 hours, an average of 40 mph, not 45.
Speed and velocity
In everyday language the two words mean the same thing. In physics, speed is how fast something moves, while velocity is speed in a given direction. A car that drives once around a 1-mile track in 2 minutes has an average speed of 30 mph, but its average velocity is zero, because it ends where it started. This calculator works with speed. For runners who think in minutes per mile, the running pace calculator is the better fit.
Frequently Asked Questions
How do you calculate speed?
Divide the distance by the time. If you drive 120 miles in 2 hours, your average speed is 120 ÷ 2 = 60 mph. Use the time in hours to get miles or kilometers per hour, and in seconds to get meters per second.
How long does it take to drive 10 miles at 30 mph?
20 minutes. Divide the distance by the speed: 10 ÷ 30 = 0.333 hours, and 0.333 × 60 = 20 minutes. At 40 mph the same 10 miles take 15 minutes, and at 60 mph they take 10 minutes.
How do I turn minutes into hours for a speed calculation?
Divide the minutes by 60. 45 minutes is 45 ÷ 60 = 0.75 hours, and 1 hour 20 minutes is 1 + 20 ÷ 60 = 1.333 hours. With this calculator you can skip the step and type the hours and minutes into their own boxes.
How far do you travel in one second at 60 mph?
88 feet, or about 26.8 meters. One mile is 5,280 feet and one hour is 3,600 seconds, so 60 mph is 60 × 5,280 ÷ 3,600 = 88 feet per second. A handy rule is to multiply mph by 1.47 to get feet per second.
If I drove 413 miles in 7 hours, how long would 531 miles take at the same speed?
9 hours. First find the speed: 413 ÷ 7 = 59 mph. Then divide the new distance by that speed: 531 ÷ 59 = 9 hours. The calculator does both steps when you fill in the first trip and then type 531 into the "same speed, another trip" line.
How do you calculate average speed for a trip with different speeds?
Divide the total distance by the total time. Averaging the speeds gives the wrong answer. Driving 30 miles at 60 mph takes 30 minutes and another 30 miles at 30 mph takes 60 minutes, so the trip is 60 miles in 1.5 hours, an average of 40 mph, not 45 mph.