Use tile-plus-joint pitch consistently in a straight grid.
Are joints between tiles being counted at both outside edges?
Use the matching calculator
Use this decision sequence
- Use actual tile dimensions and the already specified joint width.
- Identify whether the outer boundary starts and ends with a tile or includes separate edge gaps.
- For the tool’s tile-ended run, use n tiles plus n minus one internal joints.
- Keep boundary gaps, trims and openings separate from the internal grid pitch.
Keep the quantities distinct
| Quantity or assumption | How to use it |
|---|---|
| Tile length | The material piece itself. |
| Grid pitch | Tile length plus one internal joint. |
| Tile-ended outside span | n tiles plus only n minus one joints. |
Worked comparison
An illustrative row of three 0.5 m tiles with 0.01 m internal joints spans 3×0.5 + 2×0.01 = 1.52 m. Multiplying three pitches of 0.51 m gives 1.53 m and includes one extra joint. The inverse whole-grid count must use the same outside-edge convention to avoid an off-by-one tile at a purchase threshold.
Check before using the estimate
Joint width is supplied by the plan/product; this calculation does not select substrate, movement joints or installation specifications.
All dimensions, product properties, prices and specifications in this example are illustrative arithmetic inputs. Use the values from your measured plan, selected product data sheet and supplier quote. This guide does not choose construction specifications or certify safety.
Calculation and scope checked 2026-10-04. Methods and scope.