FPS to MPH Converter

Common questions

How many mph is 1 fps?

0.681818181818 mph as this page prints it. Multiply feet per second by 15/22, or 0.681818181818, to get miles per hour: 10 ft/s is 6.81818181818 mph, 30 ft/s is 20.4545454545 mph, 100 ft/s is 68.1818181818 mph, 300 ft/s is 204.545454545 mph and 1,000 ft/s is 681.818181818 mph. The other direction multiplies by 22/15, which is 1.46666666667, so 60 mph comes back as exactly 88 ft/s.

What is the formula for fps to mph?

mph = ft/s × 3600 / 5280, which reduces to ft/s × 15/22. There are 3,600 seconds in an hour and exactly 5,280 feet in a mile, so feet cancel against feet and the ratio is a definition rather than a measurement: the international foot is exactly 0.3048 metres and the international mile is exactly 1,609.344 metres. This converter carries the speed through metres per second using those defined figures instead of a rounded 0.68, which is why 300 ft/s comes back as 204.545454545 mph and not 204.

How do I convert ft/s to mph in my head?

Multiply by 0.68, which is the same as taking two thirds and adding two percent. Thirty feet per second is about 20.4 mph against the exact 20.4545454545, and 300 ft/s is about 204 mph against 204.545454545. The shortcut runs 0.27 percent low, so it is half a mile per hour short at 300 ft/s and three quarters of a mile per hour short at 400 ft/s. Use it for a quick read and use the converter when the digits matter.

Why is 60 mph exactly 88 ft/s?

Because 60 miles per hour is 60 × 5,280 = 316,800 feet in an hour, and 316,800 divided by 3,600 seconds is exactly 88. Nothing is rounded there, so the whole family is exact: 15 mph is 22 ft/s, 30 mph is 44 ft/s, 75 mph is 110 ft/s and 90 mph is 132 ft/s. Type 88 in the From box on this page and the answer reads 60, with no trailing decimals to tidy up.

Does fps mean frames per second on this page?

No, it is feet per second, the speed unit written ft/s. Frames per second is a frame rate, a count of pictures per second with no length in it, so it does not convert to miles per hour on its own: you would also need the real distance covered between one frame and the next. This page sits in the converter's Speed category, where the From menu lists the unit as Foot per second (ft/s) beside metres per second, kilometres per hour, miles per hour and knots.

What are common ft/s speeds in mph?

A brisk walk near 5 ft/s is 3.40909090909 mph, a sprinter at 30 ft/s is 20.4545454545 mph, 44 ft/s is exactly 30 mph, 88 ft/s is exactly 60 mph, an arrow from a compound bow near 300 ft/s is 204.545454545 mph, and sound in room-temperature air, roughly 1,125 ft/s, is 767.045454545 mph. Type any of them in the From box and the answer updates as you type.

Is the fps to mph conversion exact?

The ratio is exact, the decimal is not. Both the foot and the mile are defined in metres, so 15/22 is a definition and nothing here is measured or estimated, but 22 is 2 × 11 and that decimal repeats: 0.681818181818 and on forever. This page shows twelve significant digits, comfortably inside what double-precision arithmetic holds, and falls back to exponential notation only for results at or above 1e15 or below 0.000001. Plenty of pairs do land exactly anyway: 88 ft/s is 60 mph, and one foot per second is exactly 0.3048 m/s and exactly 1.09728 km/h.

Can I convert mph back to ft/s here?

Yes. The swap button between the two boxes reverses the pair without a reload, so the page becomes an mph to ft/s converter: 1 mph is 1.46666666667 ft/s, 65 mph is 95.3333333333 ft/s and 100 mph is 146.666666667 ft/s. Both unit menus stay open as well, so the same figure will go to kilometres per hour, metres per second or knots without leaving the page, and Copy result copies the headline exactly as printed, without the thousands separators.

How do I get m/s or km/h at the same time?

The list under the answer already has them, because this converter works out every speed unit at once instead of making you pick one target first. A foot per second is exactly 0.3048 m/s and exactly 1.09728 km/h, and it is 0.592483801296 knots, so 100 ft/s reads as 68.1818181818 mph, 30.48 m/s, 109.728 km/h and 59.2483801296 kn together under a heading that says 100 ft/s in every speed unit. Each row has its own Copy button.

What can I type in the From box?

Digits, one decimal point and an optional minus sign, with commas allowed as thousands separators, so 1,250 and 1250 both work, and scientific notation such as 1.25e3 is accepted too. Anything that is not a number gets a short message under the boxes telling you so, rather than a silent zero. The value carries over to the other speed units as you type, with no button to press.

Why does the page open on ft/s and mph when I last converted something else?

Because a page that names a pair should show that pair. This one sets feet per second and miles per hour on arrival, ahead of whatever the converter last remembered, and it leaves the main unit converter's own pair alone: go back there and it is still on the units you left it on. The number you last typed does travel with you, since it is usually the one you are still working on.

Is anything I type sent anywhere?

No. The conversion is arithmetic against a table of factors that ships with the page, so it runs in your browser with nothing uploaded and no account, and it keeps working with no network connection once the page has loaded.