Measure the field area
Calculate each tiled wall or backsplash run separately and include returns or niches using the same tile.
Keep different colors, trims, or orientations separate.
Build the visible module
For layout checks, the repeating module includes actual tile dimension plus intended joint.
Nominal tile size may not equal actual manufactured face dimension.
Test offset and edge cuts
Stacked, half-offset, one-third-offset, vertical, and herringbone layouts produce different cuts.
Test center lines and termination points before deciding allowance.
Convert to boxes
Use exact pieces-per-box or square-foot coverage and round upward.
Retain intentional spare tile separately after installation needs.
Verify installation instructions
Rectangular tile layout, mortar, joint width, substrate, movement accommodation, and wet-area requirements are system-specific.
Use current manufacturer guidance for the selected product.