How much paint do I need for a 12×12 room?

A 12×12 room with 8-ft ceilings, one door, and two windows needs about 2–2.5 gallons for two coats of wall paint (≈360 sq ft of wall after openings). Add ceiling paint separately — about 1 gallon for that floor area.

How many square feet does a gallon of paint cover?

Most interior latex covers 350–400 sq ft per gallon on smooth, previously painted walls. New drywall, heavy texture, or porous surfaces drop closer to 250–300 sq ft. This calculator defaults to 350.

Yes for new drywall, big color changes (especially dark to light), stains, or bare wood. On a similar-color refresh over sound paint, you can often skip primer and still get a clean finish with two topcoats.

Is this estimate a contractor bid?

No — it is a DIY planning range for materials only. Labor, prep, trim, and ceiling work are not included. Prices vary by brand and region; edit the $/gallon fields to match your store receipt.

Can I preview paint colors on my room before buying?

Yes. After you know how much paint to buy, upload a photo of your room to EasyRoomAI and redesign the walls in any style or color direction — free watermarked preview, no signup required.

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Paint calculator

Estimate gallons, primer, and material cost from room dimensions. Then preview paint colors on a photo of your actual walls.

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Room details

Length

Width

Ceiling height

Doors

Windows

Coats

Include ceilingInclude primer

Paint $/gallon

Primer $/gallon

Your estimate

gallons of paint to buy

Paintable area: 333 sq ft
Exact paint needed: 1.9 gal
Primer to buy: 1.5 gal
Estimated materials: $135

Assumes ~350 sq ft per gallon on smooth walls. Porous or textured surfaces need more. Planning estimate only — not a contractor bid.

Preview the color on your walls

Know the gallons — now see the finish. Upload a room photo and redesign wall color and style with AI before you buy a single can.

Frequently asked questions

How much paint do I need for a 12×12 room?: A 12×12 room with 8-ft ceilings, one door, and two windows needs about 2–2.5 gallons for two coats of wall paint (≈360 sq ft of wall after openings). Add ceiling paint separately — about 1 gallon for that floor area.
How many square feet does a gallon of paint cover?: Most interior latex covers 350–400 sq ft per gallon on smooth, previously painted walls. New drywall, heavy texture, or porous surfaces drop closer to 250–300 sq ft. This calculator defaults to 350.
Do I need primer?: Yes for new drywall, big color changes (especially dark to light), stains, or bare wood. On a similar-color refresh over sound paint, you can often skip primer and still get a clean finish with two topcoats.
Is this estimate a contractor bid?: No — it is a DIY planning range for materials only. Labor, prep, trim, and ceiling work are not included. Prices vary by brand and region; edit the $/gallon fields to match your store receipt.
Can I preview paint colors on my room before buying?: Yes. After you know how much paint to buy, upload a photo of your room to EasyRoomAI and redesign the walls in any style or color direction — free watermarked preview, no signup required.