Paint Quantity Calculator Guide
This guide estimates interior paint quantity in your browser. Room dimensions give gross wall area; subtracting doors and windows yields net surface. Coat count and coverage per liter set total liters, ten percent extra covers roller losses. Single-batch orders prevent shade gaps.
Step by step
- Measure inside length, width and ceiling height.
- Multiply perimeter by height for gross area.
- Measure and subtract doors and windows.
- Enter coat count and coverage value.
- Add ten percent waste, round to can sizes.
- Order one batch; calculate primer separately.
Example scenario
A 4 by 5 meter room at 2.8 meters height: perimeter 18 meters, gross walls 50.4 square meters. After 6 for openings, net 44.4. Two coats mean 88.8; at 0.12 liters each, 10.66 liters needed. With waste about 11.7 liters, one 15 liter can is practical.
Check your result
Review perimeter, height and deductions separately. Confirm net times coats. Remember primer is separate on plaster. Keep waste near ten percent, prefer one batch.
Frequently asked questions
Subtract openings?
Yes, doors and windows come off gross area.
Primer separate?
Yes, bare plaster absorbs strongly.
Two coats always?
For color changes yes; sound walls may need one.
Why one batch?
Lots can differ slightly in tone.
Roller losses?
Ten percent extra proves sufficient.
Open the tool: Paint quantity calculator →
Keep an original copy before processing your file. Examples are illustrative; results depend on your document.