The Unit Physics Actually Runs On
Every formula in dynamics, fluid mechanics, and ballistics expects velocity in meters per second — acceleration in m/s², energy in joules, Reynolds numbers dimensionless against m/s. The imperial world's answer is ft/s, the matching unit of the foot-pound-second system, and the two are locked together by the 1959 definition of the foot. Multiply by 0.3048 and a US wind-tunnel data sheet becomes a SI CFD input without losing a digit of meaning. This is the quiet conversion that runs inside every international engineering project: the aircraft performance table in ft/s, the runway certification in m/s, the same number twice.
m/s = ft/s × 0.3048
1 ft = 0.3048 m exactly
Definitional — from the 1959 agreement, zero uncertainty.
Real Speeds, Both Units
| ft/s | m/s | Context |
|---|---|---|
| 1.47 ft/s | 0.447 m/s | 1 mph — the US drivers'-ed conversion seed. |
| 44 ft/s | 13.41 m/s | 30 mph — a city speed limit. |
| 88 ft/s | 26.82 m/s | 60 mph — highway cruising, the famous 88. |
| 100 ft/s | 30.48 m/s | A strong gust — hurricane boundary layer. |
| 880 ft/s | 268.22 m/s | Subsonic rifle bullet — just under Mach 1. |
The 1.47 ft/s seed row explains the whole table: 1 mph is exactly 1.467 ft/s, so every US speed in mph converts to ft/s by multiplying by 1.467 — the number driver's-ed classes call "88 feet per second at 60 mph". From that anchor, the engineering chain extends both ways: a bullet at 880 ft/s is 268.22 m/s, dangerously close to the speed of sound (343 m/s), which is why subsonic ammunition is rated just under that figure. The same 0.3048 factor connects to the speed hub's mph and m/s pages.
Engineering Context
The reverse direction is m/s to ft/s. This pair completes the per-second row of the speed hub: mph to ft/s and ft/s to mph for the imperial speedometer, mph to m/s and m/s to mph for the direct bridge, and km/h to m/s / m/s to km/h for the metric road side. The acceleration that uses these velocities lives in the force hub, and the distance side is the length hub's feet to meters. All roads lead to the speed hub.
More: m/s to ft/s · mph to ft/s · mph to m/s · Speed Hub
Related Unit Converters
Frequently Asked Questions
How do I convert ft/s to m/s?
Multiply by 0.3048: m/s = ft/s × 0.3048. 88 ft/s (60 mph) is 88 × 0.3048 = 26.82 m/s. The factor is exact because the foot is defined as 0.3048 meters by the 1959 agreement.
Why do engineers use ft/s and m/s instead of mph and km/h?
Because physics formulas are built on meters and seconds — acceleration in m/s², force in newtons, flow in m³/s — and ft/s is the imperial system's matching unit. mph and km/h mix hours into the denominator, which breaks most equations. A wind-tunnel spec of 26.82 m/s and an aircraft data sheet of 88 ft/s are the same velocity; engineers pick the unit that fits their formula system.
What is 60 mph in ft/s and m/s?
60 mph is exactly 88 ft/s — a conversion every US driver's-ed student learns — and 88 ft/s is 26.82 m/s. The 88 comes from 60 miles × 5,280 ft ÷ 3,600 seconds. From there, every car, train, and aircraft speed can be stepped through the same two-factor chain.
More: m/s to ft/s · mph to ft/s · Speed Hub