MPH to FPS: Mental Math Calculation Conversion Formula for Miles per Hour to Feet per Second

Latest update: January 10, 2023. Page URL indicates original publication date; meanwhile, times change and the updates continue.

How to Instantly Convert MPH to FPS While Driving

- The Quick and Easy Math Trick Formula Equation -

Simply divide miles-per-hour by 2, then multiply the result by 3 to find feet-per-second.

This is the easy, quick math formula or equation to use and gives a usable, fairly accurate answer. Your answer will be accurate within 5%. As an example, 100 mph converts to 150 fps. If one does the more complicated method of math calculation (detailed further down the page), the resulting answer would be 147 fps.

"How many feet per second..." 
is a math question usually relating to cars and driving.

Easy Table Conversion from MPH to FPS Examples Chart

Divide by 2, then multiply by 3.

MPH	FPS
10	15
15	22.5
20	30
25	37.5
30	45
35	52.5
40	60
45	67.5
50	75
55	82.5
60	90
65	97.5
70	105
75	112.5
80	120
90	135
100	150
120	180
140	210
160	240

The More Difficult (and More Accurate) Answer

To prove the quick math shortcut conversion calculation works:

1. First. convert MPH (miles-per-hour) to MPM (miles-per-minute) by dividing MPH by 60.
2. Then convert miles to feet. There are 5,280 feet in one mile, so multiply MPM by 5,280 to get FPM (feet-per-minute).
3. Lastly, convert FPM to FPS (feet-per-second) by dividing by 60.

Examples of the Longhand Math Converting Miles-per-Hour (MPH) to Feet-per-Second (FPS)

MPH to FPS Math Conversion Example One

You're going 25 mph. How many feet is that per second?

1. Conversion from mph to fps is as follows: If we divide by 60, we get miles-per-minute (mpm): 25/60 = .416667.
2. For accuracy's sake, now is a good time to convert miles to feet. There are 5,280 feet in a mile so we multiply mpm times 5,280 to get feet-per-minute: 416667 x 5280 = ~2199.99 feet-per-minute [note: "~" means approximate].
3. To convert from feet-per-minute to feet-per-second (fps), we divide the answer by 60: 2199.99/60 = ~36.667 feet-per second.
4. This answer is within 5% of the one you get doing the mental easy math way, which says 25 mph divided by 2 and then multiplied by 3 equals 37.5 fps.

MPH to FPS Math Conversion Example Two

65 mph. How many feet per second?

1. Conversion from mph to fps is as follows: If we divide by 60, we get miles-per-minute: 65/60 = 1.0843333333333.This makes sense. After all, 60 miles an hour is the well-known mile-a-minute.
2. For accuracy's sake, now is a good time to convert miles to feet. There are 5,280 feet in a mile, so we multiply the miles-per-minute times 5,280 to get feet-per-minute: 1.0843333333333 x 5280 = ~5725.28 feet-per-minute.
3. To convert from feet-per-minute to feet-per-second, we divide the answer by 60: 5725.28/60 = ~95.421 feet-per second, which is the answer.
4. This coincides within 5% of the table above, which says 65 mph equals 97.5 fps. 

MPH to FPS Math Conversion Example Three

120 mph is how many feet per second? Conversion from mph to fps is as follows.

1. If we divide by 60, we get miles-per-minute: 120/60 = 2.000. This again makes sense; 60 miles an hour is the usual mile-a-minute. So 120 mph would be 2-miles-a-minute.
2. To convert miles to feet. There are 5,280 feet in a mile, so we multiply the miles-per-minute times 5,280 to get feet-per-minute: 2 x 5280 = ~10560 feet-per-minute.
3. To convert from feet-per-minute to feet-per-second, we divide the answer by 60: 10560/60 = ~176 feet-per second.
4. This number is within 5% of the table above which says 120 mph equals 180 fps.

The Reverse FPS to MPH Math Conversion Examples

Quick way to find reverse, i.e., convert from feet-per-second to miles-per hour: divide fps by 3 and then multiply by 2 for mph.

Easy Table Conversion from FPS to MPH Examples Chart

FPS	MPH
10	6.67
20	13.33
25	16.67
40	26.68
50	33.33
75	50
100	66.67
150	100
200	133.33
500	333.33
1000	666.67

Doing 20 miles-per-hour? That is 30 feet-per-second.

The laws of physics seldom take a vacation.
Most of these cars would not be able to stop in time.

- End of Article -

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