Ceiling paint calculator
Ceiling paint calculator:
gallons, primer and cost
A ceiling is not a wall lying down. Flat ceiling paint covers less per gallon, and a popcorn or knockdown finish has far more surface than its plan area suggests. This works both into the gallons, and measures the cut-in separately.
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What will it cost?
Every material the calculator worked out gets its own price. Each field starts at a typical US figure so you have something to work from — change any of them to what your own supplier charges.
These prices are approximate. They are national US retail figures, and what you actually pay varies with your region, your supplier, the season and how much you buy at once. Treat them as a starting point, not a quote — always price the job from your own supplier's current figures before you order.
Your prices
More in this series
The rest of the paint job
Each surface is bought as a different product. Work out the ones you are doing before the trip to the store.
- Paint Calculator Wall and ceiling paint, primer, rollers and tape
- Exterior Paint Calculator Gallons of exterior paint and primer by siding type, trim paint, rollers, brushes and tape
- Siding Calculator Squares of siding, panels and boxes of vinyl or planks of fiber cement, J-channel, starter strip, corner posts and nails
- Trim Paint Calculator Quarts of trim enamel and primer for baseboards, casing and crown by the linear foot, brushes, tape and caulk
- Cabinet Paint Calculator Quarts of cabinet enamel and primer for doors, drawers and frames, foam rollers, brushes and degreaser
- Fence Stain Calculator Gallons of stain or paint for both sides of a fence and its posts, by fence type and wood condition
- Primer Calculator Gallons of primer by surface and primer type, with the coats each surface needs, rollers and brushes
- Door Paint Calculator Quarts of enamel and primer for interior and front doors, one or both sides, with frames, brushes and foam rollers
- Paint Coverage per Gallon What a gallon covers on each surface, and gallons for common rooms
- Paint Sheen Chart Flat to gloss: durability, where each finish belongs, and the comparisons
- Paint Drying and Recoat Times Dry to the touch, recoat and cure times for latex, oil-based, primer, polyurethane and stain, and how weather changes them
- Spray Paint Drying Times Dry, handle, recoat and cure times for spray paint by type and surface, and how many cans a job takes
- How Many Coats of Paint and Primer Coats by color change and surface, how long to wait between coats, and coats of polyurethane and stain
- Primer Coats and Coverage How many coats of primer each surface needs, coverage per gallon by primer type, and how long each takes to dry
- Vinyl Siding Sizes and Squares What a square of siding is, vinyl panel lengths and pieces per box, Hardie and LP plank sizes, and trim per square
- Paint Can Sizes and Weights What a quart, gallon and 5 gallon bucket of paint weigh and how many square feet each one covers
Tools for the job
What makes this job easier
Tools and materials that suit this kind of job. These are affiliate links: if you buy through one, Renovimo may earn a commission at no extra cost to you. It never changes the figures on this page.
Garvee
Pro paint roller kit, 32 pieces
9 in and 4 in rollers on a telescoping pole, for walls and ceilings without a ladder.
Check price
Garvee
Telescoping scaffold plank, 69–112 in
Spans two ladders for ceilings, crown and the top of the wall.
Check price
Plastic Place
Poly sheeting, 4 mil, 10 × 100 ft
Covers floors and furniture from spatter, and tapes up as a dust wall across a doorway.
Check price
VEVOR
Folding work platform, 880 lb
A wide, height-adjustable deck to stand on along a whole wall or ceiling, instead of climbing a ladder for every stretch.
Check price
Garvee
Airless paint sprayer, 2900 PSI
Coats whole rooms, fences and siding far faster than a roller.
Check price
Garvee
House painting kit, 25 pieces
Rollers, tray, pole and drop cloth for one room — the kit the gallon count assumes you already own.
Check price
Not the tool you were after? Browse the whole range at Garvee, Plastic Place or VEVOR — the stores these picks come from.
Based on your result
What you'll need
Quantities update after every calculation. A textured ceiling wants a thicker nap than a smooth one.
- Ceiling paint
- Gallons for every coat, texture included
- Calculate above
- Stain-blocking primer
- Whole-ceiling coat where marks show
- —
- Roller covers Amazon
- Nap thickness to suit the texture
- —
- Painter's tape Amazon
- Along the wall line where you cut in
- —
- Extension pole Amazon
- Saves the ladder and your shoulders
- 1 pole
As an Amazon Associate I earn from qualifying purchases.
The maths
How this ceiling paint calculator works
Two things separate a ceiling from a wall. Flat ceiling paint goes on heavier so it does not flash under side light, which costs about an eighth of its coverage; and a textured ceiling has real surface area the plan measurement never sees.
surface = ceiling area × texture factor
gallons = ⌈ surface × coats ÷ 350 sq ft ⌉
cut-in = 2 × (width + length)
- ×1.00
- smooth
- ×1.15
- knockdown
- ×1.30
- popcorn
- 01
Measure the ceiling
Width times length, the same footprint as the floor below it.
- 02
Take out the openings
A skylight, a fan housing or a light tray the roller never crosses, each measured on its own.
- 03
Apply the texture factor
Popcorn adds about 30% more surface than its plan area, knockdown about 15%. This is the step a wall calculator has no reason to do.
- 04
Divide by ceiling coverage
About 350 sq ft a gallon, not the 400 a wall gets — flat ceiling paint is laid on heavier so it does not flash.
- 05
Prime the whole ceiling if anything is stained
A spot-primed water mark flashes through the finish and shows as a bright rectangle. Block the lot or none of it.
- 06
Measure the cut-in on its own
A ceiling has far more edge per square foot than a wall, and brushing that line is where the time goes.
Good to know
Ceiling paint questions, answered
A 12 by 12 ceiling is 144 sq ft. Smooth and in two coats that is 288 sq ft of coverage — one gallon does it at the 350 sq ft a gallon flat ceiling paint gives. Make it a popcorn ceiling and the same room needs two, because the texture adds about 30% more surface.
Because it is meant to be laid on heavier. Ceilings catch light across their surface rather than down it, so every thin patch and roller lap shows. Flat ceiling paint is formulated thick and matte to hide that, and the price of hiding it is coverage — about 350 sq ft a gallon against 400 for a wall finish.
Yes, with a stain-blocking primer, and over the whole ceiling rather than the mark. Tannin and water stains bleed straight through ordinary paint however many coats you put on. Spot-priming works on the stain but the primed patch takes the finish coat differently and shows as a bright rectangle under the light.
About 30% more than a smooth one of the same size, because you are painting the whole surface of every peak and valley rather than a flat plane. Knockdown and orange peel sit around 15%. Roll it with a thick nap, 3/4 in or more, and work slowly — a popcorn ceiling sheds if you scrub at it with a wet roller.
It will cover, but it will show every lap mark. Wall paints have more sheen and a longer open time tuned for vertical work; on a ceiling that reads as streaks wherever two wet edges met. Dedicated ceiling paint is flat, thick and often goes on pink so you can see where you have been.
Two over anything that has been painted before, and two over new primed drywall. One coat only works when you are refreshing the same colour on a sound, smooth ceiling and even then the laps tend to show. Cut in each coat before you roll it, not all the cutting first.
Ceiling first, always. It is the messiest part of the room, and anything that runs down the wall gets covered by the wall coats afterwards. Do it before the floor goes down too, if the order is yours to choose.