Rooms
Paint Settings
Sprayers use more paint due to overspray
Used to estimate total project cost
Quarts used for trim & small areas
Keep leftover paint for future touch-ups
Your Paint Estimate
—
gallons total
Finish Paint
— gal
Primer
— gal
Est. Cost
$—
Room-by-Room Breakdown
| Room | Paintable Area | Finish Paint | Primer |
|---|
Shopping List
Pro Tips
New drywall absorbs more
Unpainted drywall soaks up 20–30% more paint than a previously painted surface. Always prime new drywall first.
Dark to light needs more coats
Covering a dark color with a light one typically requires 3 coats instead of 2. Use a tinted primer to reduce coat count.
Texture eats paint
Popcorn ceilings and heavy knockdown can require up to 50% more paint than smooth surfaces. Never skip this adjustment.
Buy at least 10% extra
Store a sealed quart or gallon of your color for touch-ups. Paint batches vary slightly — future touch-ups need the same 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 orange peel texture | 300–350 sq ft | Common in newer homes |
| Heavy orange peel / knockdown | 250–300 sq ft | Add 15–20% more paint |
| Popcorn / acoustic ceiling | 150–200 sq ft | Add 50–75% more paint |
| Bare wood (first coat) | 200–300 sq ft | Wood is very absorbent |
| Masonry / brick / concrete | 100–200 sq ft | Highly porous — always prime |
| Primer (all surfaces) | 200–300 sq ft | Less coverage than finish paint |
Frequently Asked Questions
A 12×12 room with 8-foot ceilings has approximately 384 sq ft of wall space. After subtracting a standard door and window, you have roughly 320 sq ft of paintable wall area. At 350 sq ft per gallon, that's about 1 gallon per coat — so 2 gallons for two coats of walls. Add a separate quart for trim and another gallon if you're painting the ceiling.
A 10×10 room with 8-foot ceilings has about 320 sq ft of wall area. Subtract one door (21 sq ft) and one window (15 sq ft) and you're left with roughly 284 sq ft. At 350 sq ft/gallon, you'll need just under 1 gallon per coat — buy 2 gallons for two coats. Add a quart for trim.
Yes, in most cases. New drywall always needs primer — it absorbs finish paint unevenly without it, leaving blotchy results. For repaints, primer is important when switching from a dark to a light color, when covering stains or smoke damage, or when the existing paint is glossy (sand first, then prime). Tinted primer reduces the number of finish coats needed when making big color changes.
Surface texture is one of the most overlooked factors in paint estimation. Smooth walls allow a gallon to cover up to 400 sq ft. Light orange peel texture (common in newer construction) drops that to 300–350 sq ft. Heavy knockdown or skip trowel texture brings coverage down to 250–300 sq ft. Popcorn ceilings are the most extreme — they can consume 50–75% more paint than flat ceilings, dropping coverage to 150–200 sq ft per gallon.
For roller application, add 10–15% for waste. Brush application adds 5–10%. A paint sprayer adds 20–30% due to overspray and equipment coating. Always buy at least 10% extra for future touch-ups and store it in an airtight container labeled with the room, color name, and paint code. Paint batches vary slightly by dye lot — using leftover paint from the original purchase ensures the best match.
No — trim, doors, and baseboards should use a semi-gloss or gloss finish paint, which is more durable and scrubbable. Walls typically use eggshell or satin finish. Ceilings use flat/matte finish. Using the right sheen for each surface not only looks better but makes maintenance easier. Trim paint typically covers 400–450 sq ft per gallon since it goes on smooth, hard surfaces.
For vaulted ceilings, measure the actual height of each wall at its tallest point and use that in your calculation. Alternatively, calculate the wall area manually: add the area of each individual wall including the triangular sections. Our calculator uses the ceiling height you enter as the average wall height — for dramatic vaults, measure each wall separately and add the totals.
Gallons are always cheaper per ounce and are the right choice for any surface requiring more than 1 quart. Quarts (32 oz, covering roughly 80–100 sq ft) are ideal for trim in small rooms, accent walls, or touch-up reserves. If our calculator shows you need 1.1 gallons, buy 2 gallons — you'll use the second for touch-ups or you may need it before the project is done. Never try to stretch a single gallon to cover what requires 1.1.