Paint calculator
Estimate litres of paint for a surface by paint coverage, number of coats and surface factor — common reference rates.
Enter surface area and choose paint type, coats and surface condition.
Enter an area and press “Calculate paint” to see the result.
Source & verificationReference market rates
The coefficients/rates come from commonly used market references in Vietnam — not TCVN, not the applicable norms for your project. Use as a starting point and adjust to your case.
Theoretical coverage by paint type/brand and coat count — Vietnamese market reference. Porous surfaces absorb more; consider a primer coat.
About the paint calculator
Estimate litres of water-based paint for walls/ceilings — answering “how many m² does 1 litre cover” and “how many buckets does this room need”.
What you enter
Surface area to paint (m²), paint type by coverage (primer/economy topcoat/premium topcoat), number of coats and surface condition (smooth/normal/rough).
What the result means
Litres needed (including coats and surface factor) plus an indicative conversion into 18 L buckets and 5 L cans — a reference before checking the brand packaging.
Use cases
Estimating paint when repainting a home, cross-checking rates in a painting quote, answering “how many m² does an 18 L bucket cover”.
Coverage figures are common market references — each paint brand publishes its own rate (typically 8–14 m²/L/coat for topcoats). Rough surfaces, fresh putty or covering a dark colour with a light one may need more; always check the manufacturer's guidance before buying.
Worked example
A 60 m² wall, economy topcoat at 8 m²/L, 2 coats, normal surface ×1.1 → 60 ÷ 8 × 2 × 1.1 ≈ 16.5 L — about one 18 L bucket.
Frequently asked questions
How many m² does 1 litre cover?
Depends on the paint: primer ≈10 m²/L, economy topcoat ≈8 m²/L, premium topcoat ≈12 m²/L for one coat — the real rate is printed on the brand packaging.
How many coats are enough?
Typically 1 primer + 2 topcoats; repainting the same colour may need only 1–2 topcoats — coats are a separate input so you decide per the brand.
How does a rough surface affect paint?
Rough/absorbent surfaces consume more paint — the tool multiplies by 1.25; prime fresh putty walls first to reduce absorption.
Can I estimate primer separately?
Yes — pick “Primer” as the paint type and set coats to 1; run the topcoat as a separate calculation with its own coat count.
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How it works
Paint quantity (litres) = surface area ÷ paint coverage (m²/L/coat) × number of coats × surface factor.
Common reference coverage: primer ≈10 m²/L/coat, economy topcoat ≈8 m²/L/coat, premium topcoat ≈12 m²/L/coat — each brand prints its own rate on the packaging. Surface factor: smooth ×1.0, normal ×1.1, rough/absorbent ×1.25.
