Paint Calculator — How to Estimate Paint Needed
Estimate paint liters from wall area in m² (or length × height × number of walls), coats, and coverage in m²/L (default 10). Example: 40 m², 2 coats, 10 m²/L → 8 L. Optional can count assumes 3.78 L per can. Runs in your browser; numbers stay on your device and are not uploaded to a server.
How it works
Choose area or length × height × walls, enter coats and coverage in m² per liter, then calculate. Liters = area × coats ÷ coverage. If you enable cans, the tool divides liters by 3.78 and rounds up. All math runs in your browser tab; your numbers are not uploaded to a server.
Formula and assumptions
Paint volume uses wall area, coats, and label coverage:
- Area A = direct m², or length × height × number of walls (metres).
- Liters = A × coats ÷ coverage (m²/L). Default coverage is 10.
- Optional cans = ceil(liters ÷ 3.78). The 3.78 L size is an assumption for ≈1 US gallon, not a brand pack guarantee.
Example
Example: wall area 40 m², 2 coats, coverage 10 m²/L. Liters = 40 × 2 ÷ 10 = 8 L. With 3.78 L cans, cans = ceil(8 ÷ 3.78) = 3.
When to use it
- Rough-buy interior wall paint before visiting the store.
- Compare one-coat vs two-coat plans by changing the coats field.
- Cross-check a contractor quote against simple area and coverage math.
Frequently asked questions
What does coverage (m²/L) mean?
Coverage is how many square metres one liter covers per coat according to the product. The default 10 is a planning start; always prefer the label on your can.
Why offer a 3.78 L can count?
Many shops sell ≈1 US gallon cans (~3.78 L). The optional count rounds up so you see whole cans; it is not a promise that every brand packs exactly 3.78 L.
Should I enter area or length × height × walls?
Either works. Use area if you already know the m²; use length × height × walls when you have room dimensions and a wall count.
Are my numbers uploaded?
No. Dimensions are calculated in your browser on your device and are not uploaded to a server.
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