That all depends on what side of the border you are on. Nepal says the peak is at 8,848m but China says 8,844m.
This is because China argues that the mountain should be measured by rock height, excluding the metres of snow at the very top. However, the international community regularly includes snow when describing the heights of peaks around the world. In 2010 the countries came to an agreement and settled the official height as 8,848m.