The width spectrum
1/16" (rectified, precision tiles) reads seamless and modern; 1/8" is the practical standard that forgives real tiles; 3/16–1/4" suits handmade and irregular tile where the joint is part of the aesthetic. Wider joints also forgive slab movement — the joint is the room's expansion joint.
The math connection
Joint width drives grout quantity (the calculator's formula scales with it), grout type (1/8" is the sanded/unsanded boundary), and cleaning outcomes (wide joints hold more soil). Choosing joint width is choosing the maintenance profile as much as the look.
Color completes the decision
Matching grout makes tile read as the design; contrasting grout makes the GRID the design — a deliberate look that shows every joint forever. Mid-tone grout on mid-tone tile is the low-regret default that hides traffic soil between cleanings. Sample in the room's light; grout color cards lie politely.