Paint & Walls
How Much Paint Do I Need?
Enter your room dimensions and we work out paintable wall area, subtract doors and windows, apply your number of coats and turn the result into cans you can actually buy.
- 01Measure
- 02Adjust
- 03Result
- 04Shop
01 — Measure
Tell us about the job
Typical bedroom: 3–4.5 m
Typical bedroom: 3–4 m
Standard: 2.4–3 m
02 — Adjust
Material buffer
A 10% buffer covers roller absorption, touch-ups and porous patches.
Before you start — measure this
- Room length
- Room width
- Ceiling height
- Number of doors
- Number of windows
03 — Result
8.2L
Paint required
- Paintable area
- 37.1 m²
- Primer (1 coat)
- 4.1 L
04 — Shopping list
Common: 1 L, 4 L, 10 L
3 × 4 L
- Total purchased
- 12 L
- Expected leftover
- 3.8 L
Optional — planning estimate, not a live price.
Stored in this browser only. No account needed.
How we got this number
- Wall area
- 40.5 m²
- Less openings
- 3.4 m²
- Paintable area
- 37.1 m²
- × 2 coats
- 74.2 m²
- At 10 m²/L
- 7.4 L
- + 10% buffer
- 8.2 L
Planning estimate: this calculation helps you estimate material quantities. Actual requirements vary with site conditions, product coverage, installation method and waste. Confirm with the manufacturer or a qualified professional when appropriate.
What to know about this material
- Dark colours over light walls usually need an extra coat, or a tinted primer.
- Fresh plaster and bare drywall soak up paint — expect coverage nearer the low end of the range.
- Textured walls can use 10–20% more paint than a smooth surface.
Frequently asked
- How much paint do I need for a 12 × 14 ft room?
- With 8 ft ceilings, two coats and one door and window, that room needs roughly 8–9 litres (about 2.3 gallons) of wall paint at 10 m²/L coverage.
- Should I subtract doors and windows?
- Yes for anything larger than about 1 m². Smaller openings are usually left in as part of the buffer.
- How many coats do I need?
- Two coats is standard. Use three when going from a dark colour to a light one, or one coat when refreshing the same colour.
- Do I need primer?
- Prime bare plaster, drywall, patched areas and big colour changes. Primer coverage is similar to paint, so budget about one coat's worth.
- How much paint is wasted?
- Expect 5–10% between roller and tray absorption, drips and touch-ups. That is what the buffer control covers.
Related calculators
What this calculator answers
The highest-intent, lowest-competition searches this page is built to answer outright — every one of them is a quantity question you can settle above without leaving the page.
- How much paint do i needKD 42
- How many gallons of paint for a bedroomKD 25
- How much primer do i needKD 27
- How much paint for a 12x14 roomKD 0
Questions this page answers
This page is built around one job: estimate litres/gallons and cans to buy before a decorating trip.
- How much paint for a 12x14 room?
- How much paint for a bedroom with 2 coats?
- How much primer do i need for bare drywall?
- Does paint coverage change on textured walls?
Also known as: how much paint do i need, wall paint estimator, paint coverage calculator, how many cans of paint.