Sometimes called a tile saw, a masonry saw uses a diamond edged blade to cut through hard surfaces. The saw blade is continuously cooled by a flow of water that also carries the grit and dust created during the cutting away from the blade. Rent a masonry saw from a tool rental outlet or from the supplier where you purchased the pavers.
A masonry chisel breaks, rather than cuts, the paver. Score the paver by striking the surface of the paver along the line you intend to cut. Hold the beveled side of the chisel towards the waste side of the paver. Once the score line extends all the way across the top surface of the paver place the chisel at the center of the score and strike firmly with the hammer. This should break the paver at the point of the score line. Smooth any rough edges using an angle grinder.
Big projects with a lot of cutting go faster with a masonry saw. The cut by the saw will not require any cleanup with the angle grinder and can go directly to the paver project. There is also less potential for an inadvertent break in the paver that does sometimes occur when using a chisel.
The masonry saw and chisel both produce straight cuts. Use an angle grinder to shape the paver. Use this technique to create a round end for pavers used in a circular patio, for example. Always wear proper eye protection when cutting or grinding pavers.