Material Waste Factor Calculator

How to use it

1. Measure the quantity neta exact of material necessary según drawings and measurements of project
2. Determine the factor of waste según the material: 5-10% to bricks and blocks, 10-15% to baldosas and azulejos, 3-5% to materials a granel
3. Apply the fórmula: quantity a pedir = quantity neta × (1 + waste/100). Este is the order current to the supplier
4. Calculate the units of waste: quantity_pedida − quantity_neta (material that pierde in cortes, roturas, ajustes)
5. Multiply the waste per the price unitario to find the cost of the waste
6. Ajusta the factor of waste según the complejidad of the corte and the experiencia of the skilled worker

Common mistakes

• ⚠️ Apply the same factor of waste a all the materials: the baldosa large rompe más that the brick estándar
• ⚠️ Not considering waste additional in obras with many recortes, esquinas, columns or installations vistas
• ⚠️ Pedir justo the quantity neta without waste and quedarse corto a mitad of the project (retrasos and costs of envíor extra)
• ⚠️ Not negotiating with the supplier the devolución of material sobrante in buen estado (palets completos without abrir)
• ⚠️ Forget that the waste también generates costs of gestión of waste (to carry rubble to the vertedero)

Worked example

Calculate 10% waste factor for 100m2 of tiles.

Results: {quantity_pedir} units a pedir, {quantity_merma} units of waste, cost of waste of {coste_merma_eur} €, cost total of {coste_total_eur} €.

Input guide