油漆用量计算器
需要多少油漆？输入房间尺寸，获取任何涂漆项目所需的加仑数、升数和成本估算。
PaintCalculator.roomDimensions
PaintCalculator.doorsWindows
Standard door ≈ 18 sqft · standard window ≈ 12 sqft
PaintCalculator.paintSettings
结果
PaintCalculator.paintNeeded
1.77
PaintCalculator.gallons
PaintCalculator.cansToBuy
2
1 gal each
PaintCalculator.coverageNote
How Much Paint Do I Need?
The standard formula for estimating paint is straightforward: calculate the total wall area, subtract doors and windows, then divide by the paint's coverage rate (in square feet per gallon). Multiply by the number of coats and round up to the nearest can.
This calculator handles all the maths automatically. Just enter your room dimensions, choose your paint type, set the number of coats, and read the results.
Paint Coverage by Finish Type
| Paint Finish | sqft / gallon | m² / litre | Best for |
|---|---|---|---|
| Flat / Matte | 350 | 8.6 | Ceilings, low-traffic walls |
| Eggshell / Satin | 325 | 8.0 | Living rooms, bedrooms |
| Semi-Gloss | 300 | 7.4 | Kitchens, bathrooms, trim |
| Gloss | 280 | 6.9 | Doors, cabinets, woodwork |
| Primer / Undercoat | 250 | 6.1 | New drywall, colour changes |
Tips for Accurate Paint Estimates
Buy 10% extra
Always purchase slightly more than calculated. You'll need it for touch-ups, holidays in coverage, or a future small repair.
Two coats is standard
Most quality finishes require two coats for even colour and durability. Budget your paint accordingly from the start.
Prime bare surfaces
New drywall, wood, or a dramatic colour change needs a coat of primer first. Primer typically covers less area (250 sqft/gal) than finish paint.
Account for texture
Rough or heavily textured walls absorb more paint than smooth ones. Add up to 20% extra for heavily textured or masonry surfaces.
Frequently Asked Questions
How much paint do I need for a 12x12 room?
A 12x12 room with 8-foot ceilings has roughly 320 sqft of wall area. For two coats at 350 sqft/gal, you need about 2 gallons — so buy 2 one-gallon cans.
How many square feet does a gallon of paint cover?
Typically 250–400 sqft depending on finish. Flat/matte: ~350 sqft/gal. Eggshell/satin: ~325 sqft/gal. Semi-gloss: ~300 sqft/gal. Primer: ~250 sqft/gal.
How many coats of paint do I need?
Two coats gives a professional finish in most cases. One coat may work for same-colour touch-ups. Three coats for dramatic colour changes or porous surfaces.
Should I buy extra paint?
Yes — always buy 10% more than calculated to account for touch-ups and surface variation. This calculator rounds up to full cans, which already provides a small buffer.
Does the calculator include ceiling paint?
Yes. Check the 'Include ceiling' box to add ceiling area. Ceiling paint often has different coverage, so you may want to calculate it as a separate run.
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