How to Calculate Room Renovation Costs? A Step-by-Step Guide

Estimating a budget is the single most important phase of any home renovation. Whether you are refreshing a single bedroom or finishing a brand new apartment, precise calculations help avoid unexpected costs. In this guide, we will walk you through calculating finishing materials and labor costs.

1. Take Precise Room Dimensions

Before buying any supplies, you need to know the actual dimensions of your space:

Floor Area: Multiply room width by length.
Wall Area: Measure the perimeter of the room and multiply by the ceiling height.
Deduct Openings: Calculate the total area of windows and doors, then subtract it from the wall area. This ensures you do not overbuy paint or tiles.

2. Estimate Material Requirements

Painting

Paint coverage is usually listed as square meters per liter (sqm/L) per single coat. Most projects require two coats. $$\text{Paint needed (L)} = \frac{\text{Wall area} \times 2}{\text{Coverage per Liter}}$$

Flooring and Laminate

When purchasing floor planks or tiles, always account for a waste safety margin:

Straight layout: 5-10% waste
Herringbone pattern: 15% waste

3. General Labor Rates

Contractor prices vary significantly by region. Standard estimates:

Painting (two coats): $5 - $10 per sqm
Laminate flooring: $12 - $22 per sqm
Wall/floor tiling: $30 - $60 per sqm

Use our free interactive 2D Planner on the Reno Costify homepage to draw your room layout and instantly export a complete PDF budget!