Heisenberg's Uncertainty Principle's inequality
As andynitrox said in the comments :  


  The HUP just gives a lower bound in the uncertainty of Δx and Δpx, it is of course possible to measure both quantities with a higher uncertainty than given by the HUP, but not less.


The inequality exists to show that, the uncertainty is atleast this much and in real-life cases, its much larger than this . (source)(provided by Mithoron)