Linear Speed Calculator
Convert roller diameter and RPM to surface speed, or reverse it.
Results
Linear surface speed
- This is surface speed at the effective diameter; travel speed assumes no slip.
The result is the tangential speed at the entered diameter. Conveyor or vehicle travel speed equals this value only when there is no slip. Loaded tire deformation and belt pitch diameter can change the effective diameter. Zero speed with zero RPM cannot determine a unique diameter.
Formula · How it works
Formula
v = πDn / 60n = 60v / (πD)D = 60v / (πn)Surface speed v = πDn/60, where D is diameter in m, n is rpm and v is m/s. Inverse formulas are n = 60v/(πD) and D = 60v/(πn). One revolution moves a point on the circumference through πD.
Worked example
A 1 m diameter wheel rotating at 60 rpm has a surface speed of π m/s ≈ 3.14159 m/s, 188.50 m/min or 11.31 km/h. Entering that speed and 1 m returns 60 rpm.
How it works
Surface speed increases directly with both diameter and RPM. Doubling either one doubles the speed. Unit conversions preserve the same physical speed; for example, 1 m/s equals 60 m/min and 3.6 km/h.
Common questions
Can I calculate conveyor belt speed?
Yes, using the effective diameter and RPM of the roller driving the belt. The result assumes the belt moves with the roller without slip.
Why must speed and RPM be positive in diameter mode?
At zero RPM, division is undefined and zero surface speed does not identify a unique diameter. Positive RPM with zero speed would imply a zero diameter, which is outside the physical model.
Can the result be zero?
Yes. A valid positive diameter at zero RPM has zero surface speed. Likewise, zero surface speed with a positive diameter gives zero RPM.