Overview
This calculator turns wall or ceiling measurements into a practical paint order. It uses the surface area, the paint’s stated coverage, the number of coats, a waste allowance, and the can size to estimate both the liquid volume and the container count. It is useful when you are repainting a room, coating a ceiling, or dealing with surfaces that drink more paint than smooth plaster. The result shows the base amount and the adjusted amount after waste, so you can plan the purchase before you open the first can. For the best estimate, use the exact coverage printed on the product label and not a generic average. Rough finishes, patch repairs, and strong color changes usually increase consumption, so the waste field helps you reflect the real job rather than the ideal one.
Use cases
- Repainting a living roomEstimate the liters needed before covering a large living room with two finish coats.
- Sizing a ceiling orderCheck whether a ceiling fits into one 5 L can or needs a larger container.
- Choosing between two paintsCompare two products with different coverage values for the same room and coat count.
- Planning a multi-room jobAdd the paint demand for several rooms and buy the right number of cans at once.
- Accounting for rough wallsAllow extra paint for textured plaster, repaired sections, and porous surfaces.
How it works
- 1
Enter the surface to be painted in square meters.
- 2
Use the coverage value from the paint label, in m2 per liter.
- 3
Select how many coats the finish requires.
- 4
Add waste for rollers, brushes, edges, touch-ups, and absorption.
- 5
Divide the final liters by can size and round up to whole cans.
Examples
Medium bedroom with two coats
Input: Area: 32 m2, coverage: 11 m2/l, coats: 2, waste: 8%, can size: 2.5 l
Output: Paint without waste: 5.82 l, paint with waste: 6.28 l, cans: 3.
A room of this size usually needs three small cans once waste is included.
Kitchen ceiling only
Input: Area: 18 m2, coverage: 9.5 m2/l, coats: 2, waste: 12%, can size: 10 l
Output: Paint without waste: 3.79 l, paint with waste: 4.24 l, cans: 1.
A flat ceiling often fits in one large can, even with a modest waste allowance.
Textured hallway walls
Input: Area: 54 m2, coverage: 8.5 m2/l, coats: 2, waste: 15%, can size: 5 l
Output: Paint without waste: 12.71 l, paint with waste: 14.62 l, cans: 3.
A rough hallway can move the purchase from two cans to three.
FAQ
Does the calculator count each coat separately?
Yes. The surface area is multiplied by the number of coats before coverage is applied, so two coats require twice the base amount.
Why can the result be higher than the label coverage suggests?
Because waste can include roller loss, tray residue, brush work, touch-ups, and extra absorption in the surface. With waste set to zero, you get the theoretical minimum.
What should I enter for textured walls or patched areas?
Use a lower coverage value and a higher waste percentage. Those surfaces typically take more paint than smooth, sealed plaster.
Should I enter the nominal can size or the actual paint volume?
Enter the actual volume of paint in the container. If the can holds 2.5 L, use 2.5 rather than the product line name.
How should I read a result like 2.1 cans?
Round up to 3 cans. Paint cannot be bought in fractions, and the extra amount leaves room for touch-ups and color matching.