RPM to Linear Velocity Calculator

Find the circumference with 2 x pi x radius, multiply it by the RPM, then divide by 60 to move from per-minute to per-second. The result is the surface speed in metres per second, which the tool also expresses in km/h.

Diameter is twice the radius. If you choose Diameter from the selector, the tool halves your value first and then uses 2 x pi x radius for the circumference, so both modes give the same speed for the same physical wheel.

Metres per second is the base SI unit, but a km/h figure is often easier to picture for wheels and vehicles. It is simply the m/s value multiplied by 3.6.

Yes. The surface speed of a point on the rim is its tangential speed, the distance it travels along its circular path each second. It is the speed you would measure with a tape running along the surface.

RPM is revolutions per minute and the size must be in metres. For a 100 mm radius enter 0.1, and for a 12 mm radius enter 0.012. The outputs are then metres per second, km/h and metres of circumference.

An RPM of zero is allowed and returns a speed of zero. The radius or diameter must be greater than zero, and negative sizes are rejected with a short message, since a wheel cannot have a negative radius.

The engine keeps full precision and rounds only at the ninth decimal, so you see the exact computed value rather than a truncated estimate. Round it yourself to whatever precision your job needs.

No. The math runs entirely in your browser, so nothing you type is uploaded. That also means it keeps working offline once the page has loaded.