Mesh versus rebar grid
Rolled wire mesh comes in sheets or rolls laid flat on chairs; a rebar grid is bars tied at each intersection. Both are measured the same way — <strong>bars in one direction plus bars in the other, at your spacing</strong>. The calculator returns total linear footage so you can buy either 10-foot rebar lengths or mesh rolls by coverage.
Support it or waste it
Unsupported mesh ends up at the bottom of the slab doing almost nothing. Use mesh chairs every couple of feet, pull the sheet flat mid-pour with a hook, and overlap adjacent sheets one full mesh square. The 10% extra in the calculation covers overlaps and edge trimming.