##\displaystyle \Delta x \Delta p \geq \frac{\hbar}{2}##. Let ##\displaystyle \Delta x = \lambda = \frac{h}{p}##, then ##\displaystyle \Delta p \geq \frac{\hbar}{2 \Delta x} = \frac{\hbar p}{2 h} = \frac{p}{4\pi}##.
If the motion is non-relativistic, p=mv and ##\displaystyle \Delta v \geq \frac{v}{4\pi}##.
Note that this is a lower limit on the uncertainty.