01
Formula used
margin % = (selling price − cost) ÷ selling price × 100 · markup % = (selling price − cost) ÷ cost × 10002
Worked example
A 60 × 60 cm tile priced at €20/m² costs €7.20 per tile; a box of four tiles is €28.80.
03
Common mistakes
- Confusing margin with markup.
- Mixing prices including and excluding tax.
- Using nominal tile dimensions instead of the declared box coverage.
04