Feet per Second to MPH Calculator
88 feet per second = 60.0000 miles per hour
Common values
Convert feet per second to miles per hour and back, plus km/h, knots and m/s. Multiply ft/s by 0.6818 to get mph — or just type and read.
- Exact: 1 mile = 5,280 ft
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How do you convert ft per second to miles per hour?
To convert feet per second to miles per hour, multiply by 0.681818. The factor comes from 3,600 seconds in an hour divided by 5,280 feet in a mile. So 100 ft/s × 0.6818 = 68.18 mph. To go the other way, multiply mph by 1.466667 to get ft/s.
Formula
mph = ft/s × 0.681818…
ft/s = mph × 1.466667…
The factor is 3,600 ÷ 5,280 exactly. Both decimals repeat, so the calculator uses the fraction internally and only rounds on display.
Conversion factors verified
What is the feet per second to mph conversion?
Converting feet per second to miles per hour multiplies by 3,600 and divides by 5,280, because there are 3,600 seconds in an hour and 5,280 feet in a mile. That simplifies to the exact fraction 15/22, or 0.681818… as a decimal — a rational number, not an approximation, so the conversion is exact even though the decimal repeats. The reverse multiplies by 22/15, or 1.466667. This produces two unusually clean landmarks that appear in almost every physics textbook: 88 ft/s is exactly 60 mph, and 44 ft/s is exactly 30 mph. The practical consequence is worth knowing: at 60 mph a vehicle covers 88 feet every second, which is why reaction distance alone runs to roughly 132 feet at typical human response times. Sound travels about 1,116 ft/s at sea level, or 761 mph.
Travel time
How long does a distance take at a given speed?
Distance divided by speed, with the unit conversion handled for you — the question behind most ft/s searches.
How long does that take?
Enter a distance in feet and a speed in mph. The time updates as you type.
Overview
About the ft/s to mph converter
Feet per second and miles per hour describe the same thing at different scales. Physics problems, ballistics tables and machine specifications tend to use ft/s; vehicles, weather reports and everyday speech use mph. Converting between them is a single multiplication, but it is one people get backwards constantly.
The useful mental shortcut is that ft/s is roughly two-thirds of mph. A ball thrown at 60 ft/s is moving at about 41 mph; a car at 60 mph covers 88 feet every second. That second figure is worth memorising — it is why stopping distances grow so fast.
This converter also handles knots and metres per second, and there is a separate travel-time calculator below for working out how long a given distance takes at a given speed.
Method
How it's calculated
Multiply feet per second by 3,600 to get feet per hour, then divide by 5,280 to get miles per hour. Combined, that is a single factor of 3,600 ÷ 5,280 = 0.681818…, which repeats forever and so is held as a fraction internally rather than as a rounded decimal.
Going the other way, multiply mph by 5,280 ÷ 3,600 = 1.466667… That is the origin of the well-known rule that 60 mph is 88 ft/s: 60 × 1.4667 = 88 exactly.
Going the other way, miles to feet does the reverse conversion. If you want a figure already worked out, conversion chart lists the common ones, and about & methodology documents every constant used here and where it comes from.
Examples
Worked examples
The arithmetic in full, using values people search for.
A car at 60 mph, in feet per second
- 1Start with 60 mph.
- 2Multiply by 5,280 to get feet per hour: 316,800.
- 3Divide by 3,600 seconds in an hour.
60 mph = 88 ft/s exactly — the car covers 88 feet every second.
A 100 ft/s projectile, in mph
- 1Start with 100 ft/s.
- 2Multiply by 0.681818.
- 3Round to two decimal places.
100 ft/s = 68.18 mph.
How long to cover 43 ft at 77 mph
- 1Convert the speed to ft/s: 77 × 1.466667 = 112.93 ft/s.
- 2Divide the distance by the speed: 43 ÷ 112.93.
- 3Read the result in seconds.
43 ft at 77 mph takes 0.381 seconds — about a third of a blink.
Key facts
What to remember
- 1 ft/s = 0.681818… mph. The factor is 3,600 ÷ 5,280 exactly.
- 1 mph = 1.466667… ft/s. So 60 mph = exactly 88 ft/s.
- A useful approximation: ft/s ≈ mph × 1.5, and mph ≈ ft/s × 0.68.
- 1 knot = 1.6878 ft/s, because a nautical mile is 6,076.1 feet, not 5,280.
- 1 m/s = 3.2808 ft/s = 2.2369 mph.
- Human running speed tops out near 40 ft/s (27 mph); a commercial jet cruises near 800 ft/s (550 mph).
Accuracy
Assumptions and precision
Both conversion factors are repeating decimals, so any displayed value is rounded. The calculator holds the exact fraction internally and rounds only at the last step, which is why 60 mph returns exactly 88 ft/s rather than 87.9999.
The calculator never rounds internally. Rounding happens once, when a figure is drawn on screen, at the precision you choose with the slider — so converting a value and converting it back returns your original number exactly.
Applications
Who uses this conversion
The same arithmetic, for different reasons.
Physics students
Kinematics problems are posed in ft/s but intuition lives in mph. Converting is how an abstract velocity becomes a speed you can picture.
Drivers and safety analysts
Reaction distance is speed in ft/s multiplied by reaction time. At 60 mph that is 88 feet per second of hesitation.
Pilots
Vertical speed is in feet per minute, ground speed in knots. Moving between the two is constant work in the cockpit.
Coaches and sports scientists
Sprint splits are measured in ft/s from video, but reported in mph. The conversion is the last step of every analysis.
FAQ
Speed conversion, answered
Direct answers to the questions people search for on this topic.
How long does it take to travel 43 ft at 77 miles an hour?
How many ft/s is 60 mph?
Why does multiplying ft/s by 0.6818 give mph?
How do you convert miles/hr to ft/s?
Is a knot the same as a mile per hour?
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Convert your speed now
Feet per second, miles per hour, km/h, knots and m/s — converted live, with a travel-time calculator built in.