1
Your Room
2
Surfaces
3
Paint Settings
Step 1 — Your Room
Enter your room dimensions or choose a common room size.
Step 2 — What Are You Painting?
Select all surfaces you're painting, then answer a few quick questions.
Surface Details
Step 3 — Paint Settings
Tell us about your paint and we'll calculate exactly how much you need.
Your Paint Estimate
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gallons total
Paint
0 gal
Primer
0 gal
Est. Cost
$0
Room-by-Room Breakdown
| Room | Paintable Area | Paint | Primer |
|---|
Shopping List
Pro Tips
New drywall absorbs more
Unpainted drywall soaks up 20-30% more paint. Always prime new drywall first.
Dark to light needs more coats
Covering a dark color with a light one typically needs 3 coats. Use a tinted primer to reduce coat count.
Texture eats paint
Popcorn ceilings can require up to 50% more paint than smooth surfaces.
Buy at least 10% extra
Store a sealed quart for touch-ups. Paint batches vary by dye lot.
Paint Coverage Rate Reference
| Surface / Condition | Coverage per Gallon | Notes |
|---|---|---|
| Smooth drywall (repaint) | 350-400 sq ft | Best case scenario |
| Smooth drywall (new/primed) | 300-350 sq ft | After primer coat |
| Light texture (repaint) | 300-350 sq ft | Common in newer homes |
| Heavy texture / knockdown | 250-300 sq ft | Add 15-20% more paint |
| Popcorn / acoustic ceiling | 150-200 sq ft | Add 50-75% more paint |
| Trim and baseboards | 400-450 sq ft | Smooth surface, excellent coverage |
| Interior doors | 400-450 sq ft | Always smooth, great coverage per gallon |
| Vinyl / fiber cement siding | 300-350 sq ft | Exterior — clean thoroughly first |
| Wood siding | 250-300 sq ft | Porous — prime bare wood first |
| Stucco | 100-150 sq ft | Very porous — always prime |
| Brick | 75-100 sq ft | Highly absorbent — masonry paint recommended |
| Concrete / cinder block | 100-125 sq ft | Use masonry paint or elastomeric |
| Primer (all surfaces) | 200-300 sq ft | Less coverage than finish paint |
Frequently Asked Questions
One gallon of paint covers approximately 350 square feet per coat on smooth surfaces. That works out to roughly 1 sq ft needing about 0.003 gallons of paint per coat. For two coats — which is standard — you need about 0.006 gallons per square foot. So a 500 sq ft area needs roughly 3 gallons for two coats. Surface texture reduces coverage significantly — light texture drops to about 300 sq ft per gallon, and popcorn ceilings can drop to 150-200 sq ft per gallon. Use our calculator above to get a precise estimate based on your exact room dimensions and surface type.
Yes — our paint calculator includes trim and baseboards as part of the Other Surfaces option in Step 2. When selected it automatically calculates the paint needed for trim, baseboards, doors, and closets based on your room dimensions. Trim and baseboards are always smooth surfaces and typically cover 400-450 sq ft per gallon, more than walls or ceilings. A standard room usually needs 1-2 quarts for trim and baseboards.
The amount of paint you need depends on the size of the surface, the number of coats, and the paint coverage rate. One gallon covers about 350 sq ft per coat. For a standard 12x12 bedroom you need approximately 2 gallons for two coats on the walls, plus a gallon for the ceiling and a quart for trim.
Measure wall length and width, multiply by ceiling height to get total wall area, subtract 21 sq ft per door and 15 sq ft per window, then divide by your paint coverage rate (typically 350 sq ft per gallon). Multiply by number of coats and add 10% for waste.
A 12x12 room with 8-foot ceilings needs approximately 2 gallons for two coats on the walls. After subtracting one door and one window you have roughly 320 sq ft of paintable area. At 350 sq ft per gallon that is just under 1 gallon per coat.
A 10x10 room with 8-foot ceilings needs approximately 2 gallons for two coats on the walls. After subtracting one door and one window you have roughly 284 sq ft of paintable area. At 350 sq ft per gallon that is just under 1 gallon per coat.
You need primer when painting new or bare drywall, bare wood, or masonry. You also need primer when going from a very dark color to a much lighter one, when covering stains, or when painting over a previously glossy surface. If repainting a clean wall in a similar color you can usually skip primer.
Smooth walls allow a gallon to cover up to 400 sq ft. Light texture drops that to 300-350 sq ft. Heavy knockdown texture brings coverage down to 250-300 sq ft. Popcorn ceilings can consume 50-75% more paint than flat ceilings.
They can use the same paint but it is not recommended. Ceiling paint is typically flat or matte finish. Wall paint is usually eggshell or satin which is easier to clean.
For roller and brush application add 10-15% for waste. A paint sprayer adds 20-30% due to overspray. Always buy at least 10% extra for future touch-ups stored in an airtight container labeled with the room and color code.
Gallons are always cheaper per ounce. Quarts covering roughly 80-100 sq ft are ideal for trim in small rooms or touch-up reserves. If the calculator shows 1.1 gallons needed, buy 2 gallons and use the extra for touch-ups.