About this tool
The Paint Calculator estimates how much paint you need for a room or surface based on dimensions and the coverage rate of your paint. It is built for homeowners, renters, and contractors who want to avoid buying too much or running short mid-project. Enter your wall measurements and the calculator does the math for you, accounting for standard coverage rates per litre.
Reach for this tool before any interior or exterior painting job. It is especially useful when you are comparing paint brands with different coverage specs, budgeting a multi-room renovation, or trying to figure out whether one coat will stretch far enough given the colour change involved.
How to use it
- Enter the width and height of each wall or surface you plan to paint.
- Input the number of coats you intend to apply.
- Subtract window and door areas if the calculator provides that option.
- Enter the coverage rate from your paint can label, typically in square metres per litre.
- Review the estimated litres needed and round up to the nearest available can size.
Pro tips
- Always add a ten percent buffer to your total before purchasing, especially for textured walls that absorb more paint than smooth surfaces.
- If switching from a dark to light colour, input three coats minimum so the estimate reflects real-world coverage needs.
FAQ
What coverage rate should I use if I do not have the paint can yet?
A safe default is ten square metres per litre for standard interior latex paint. Premium paints often cover twelve to fourteen square metres per litre, so check the label once you choose a product.
Does this calculator account for ceilings?
You can add the ceiling as a separate surface by entering its width and length as an additional wall. Keep ceiling paint separate in your calculation since it typically has a different coverage rate.
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