How does one calculate a stocks resistance level?

When looking at the chart for any stock, the last resistance level is simply the last high the stock failed to break. If you run this back, you can see all the stocks highs. Traditionaly, there will be some point (price) which it hits and rebounds back off(drops). This is resistance. This is the point that the market (buyers) thinks is too much to pay for the stock, the point at which they deem it overvalued.