RPM to hertz
Divide by 60. Use it for motor specs and anything quoted per second. Deep page: RPM to Hz.
↔ ÷60
3,600 rpm ÷ 60 s/min = 60.00 Hz
RPM to radians per second
Multiply by 2π/60. Use it for kinematics and torque-power math. Deep page: RPM to rad/s.
↔ ×2π/60
3,000 rpm × 2π/60 = 314.16 rad/s
Engine RPM to road speed
Chain the gear ratio, final drive and tire circumference. Deep page with the tire-size arithmetic: RPM to mph.
63.3mph
wheel rpm = 3,000 ÷ (0.9 × 3.9) = 854.7
tire dia = 16″ × 25.4 + 2 × (205 × 55%) = 632 mm; circumference = 1.985 m
speed = 854.7 × 1.985m × 60 ÷ 1609.344 = 63.3 mph
Which converter for which problem
- Motor or drive spec quoted in Hz (a 50 Hz pump, a 120 Hz spindle): the Hz tool.
- Physics homework or torque-power equations(P = τω): the rad/s tool.
- Gearing questions (what will the engine turn at 70 mph in sixth): the mph tool, run in either direction.
The factors and their standards backing are on the unit page.