How much exterior paint do I need?
Siding, stucco and trim worked out from the outside of your house, not its floor plan. A calculator, a chart for common Front Range house sizes, and the coverage figures printed on real product data sheets.
By Painter Hotline · Updated
Multiply the distance around your house by the wall height, add the triangles under each gable, subtract doors, windows and the garage door, then multiply by the coats and divide by the coverage on the data sheet. Exterior acrylic covers about 250 to 300 square feet a gallon, so a typical two-story, 2,000 square foot house needs 14 to 17 gallons for two coats.
Exterior paint calculator
Measure the footprint of the house on the outside (a long tape or a measuring wheel works; so does the scale on a property map). The defaults are a two-story house about 25 by 40 feet. Change anything.
How do you measure a house for exterior paint?
Floor area tells you surprisingly little about an exterior. A 2,000 square foot two-story and a 2,000 square foot ranch have very different amounts of wall, because the two-story stacks its floors and has a smaller footprint. Measure the outside instead.
1. Perimeter times height
Walk the house and add up every wall length. A simple rectangle is two times length plus width; for an L-shaped or bumped-out house, measure each run. Multiply by the height from the foundation line to the eaves. If you cannot reach that high with a tape, allow about 9 feet per story; that covers the floor framing between levels as well as the ceiling height.
2. Add the gables
A gable is the triangle of wall under a peaked roof. Its area is half the width times the height from the eave line to the peak. A 25-foot gable that rises 6 feet adds 75 square feet, and most houses have two. Dormers and pop-outs add their own small walls.
3. Take out what you will not paint
Subtract about 21 square feet for each entry door, 15 for a typical window, and 112 for a standard 16 by 7 foot garage door if it is not getting the body color. If the garage door is being painted, leave it in and count it once.
4. Coats and coverage
Divide by the coverage printed on the product data sheet, then multiply by the number of coats. Sherwin-Williams’ Duration exterior acrylic, for example, lists 250 to 300 square feet per gallon and says to use one coat on a repaint and two on new, bare surfaces. In practice, a color change, a south wall that has chalked badly, or patches of bare wood all mean two coats.
Put together: (perimeter × height + gables − openings) × coats ÷ coverage = gallons.
How much paint does a typical house exterior take?
The table runs the calculator for five common Front Range house shapes. Each one assumes 9 feet of wall per story, two gables rising 6 feet, two entry doors and the window and garage counts listed. Body figures are for two coats; trim assumes 6-inch boards (fascia around the house plus window and door casings), two coats at 275 square feet per gallon.
| House | Footprint | Paintable wall | Acrylic, 2 coats (250–300) | Elastomeric system (115–160) | Trim |
|---|---|---|---|---|---|
| 1-story ranch, 1,200 sq ft | 30 × 40, 10 windows, 1 garage door | 1,136 sq ft | 7.6–9.1 gal | 7.1–9.9 gal | 1.3 gal |
| 1-story ranch, 1,800 sq ft | 36 × 50, 12 windows, 1 garage door | 1,430 sq ft | 9.5–11.4 gal | 8.9–12.4 gal | 1.6 gal |
| 2-story, 2,000 sq ft | 25 × 40, 16 windows, 1 garage door | 2,096 sq ft | 14.0–16.8 gal | 13.1–18.2 gal | 1.7 gal |
| 2-story, 2,800 sq ft | 28 × 50, 18 windows, 2 garage doors | 2,440 sq ft | 16.3–19.5 gal | 15.3–21.2 gal | 2.0 gal |
| 2-story, 3,500 sq ft | 35 × 50, 22 windows, 2 garage doors | 2,674 sq ft | 17.8–21.4 gal | 16.7–23.3 gal | 2.3 gal |
Two things stand out. The 2,000 square foot two-story has nearly 50% more wall than the 1,800 square foot ranch, even though it has less floor space per level. And the elastomeric column is close to the acrylic column even though elastomeric goes on far thicker, because its coverage figure is for the whole two-coat system rather than per coat.
Does stucco, brick or rough wood take more paint?
Yes, and by a lot. The surface decides coverage far more than the brand does.
- Smooth lap siding and fiber cement come closest to the number on the can. Use the middle of the data-sheet range.
- Rough-sawn wood, T1-11 and cedar shingles soak up paint and have more surface area than their flat measurement suggests. Use the low end of the range or below it, and check the data sheet for a separate rough-surface figure; many stain and paint sheets list one.
- Stucco with ordinary exterior paint also runs below the label because of the texture. Sherwin-Williams’ Duration sheet adds that new stucco should cure about 30 days before painting.
- Stucco with an elastomeric coating is a different product altogether: a thick, flexible film that bridges hairline cracks. Sherwin-Williams’ elastomeric guide lists ConFlex SherLastic at 115 to 160 square feet per gallon for a two-coat system, or 60 to 80 for a single heavy coat, with 24 hours between coats.
- Brick that has never been painted is porous and usually needs a masonry primer first. Painting brick is a one-way decision, so it is worth getting advice before buying anything.
When in doubt, buy for the low end of the coverage range. Extra unopened, untinted paint can often go back; running short halfway up a wall means a second trip and, if it is a different batch, a possible color shift.
How much paint do you need for exterior trim?
Less than people expect. Trim is measured in linear feet: the fascia boards along the eaves and rakes, corner boards, and the casings around every window and door. Multiply the total length by the board width in inches and divide by 12 for square feet. A house with 450 feet of 6-inch trim has about 225 square feet of it, which is under 2 gallons for two coats.
If you leave the trim field in the calculator blank, it estimates trim as the perimeter of the house plus 16 feet per window, 20 per door and 30 per garage door. That is a reasonable starting guess for a simple house; ornate Victorian trim, deep soffits and decorative brackets can double it.
Soffits are measured as area (length times depth) rather than linear feet, and they often get the trim color. Front doors take about a quart for two coats on one side.
Should you buy 5-gallon buckets or single gallons?
For the body color on a whole house, 5-gallon buckets are easier to work from and keep the color consistent, because everything in the bucket was tinted together. Buy the body color in as few batches as possible, and if you do end up with several containers, pour them together in a large bucket before you start. This is called boxing the paint, and painters do it on every exterior.
Buy trim and door colors in gallons and quarts. Keep a labeled quart of every exterior color for touch-ups; on a Front Range south wall you will probably want it within a few years.
Whatever is left, Colorado’s PaintCare program takes it at no charge. Our interior room calculator has the drop-off details and the arithmetic for walls, ceilings and trim inside.
Is it worth painting the exterior yourself?
The paint is the cheap part. Angi’s Denver exterior guide puts a professional job at $1.55 to $4.10 per square foot, about $3,250 on average, with labor at $26 to $102 an hour per painter. Most of that is labor and preparation, which is exactly what a homeowner contributes for free, and exactly where DIY exteriors fail: skipped washing, no scraping, caulk over gaps that needed filler, and a single thin coat.
A one-story ranch you can reach from a stepladder is a fair summer project. Two-story walls, steep lots, peeling paint on a house built before 1978, and anything that needs a lift are where most people call. Our guide to how long a paint job takes shows what a professional week looks like, and the exterior crew page covers what our preparation includes. If you would rather have the number than the math, a photo estimate is free.
Exterior paint questions
How many gallons of paint does it take to paint a 2,000 square foot house exterior?
For a two-story, 2,000 square foot house with a 25 by 40 foot footprint, about 2,100 square feet of wall needs 14 to 17 gallons for two coats at 250 to 300 square feet per gallon, plus about 2 gallons of trim paint. A single-story house of the same floor area has less wall and needs less paint.
How do I calculate the square footage of my house exterior?
Add up the length of every outside wall, multiply by the wall height (about 9 feet per story if you cannot measure it), and add half the width times the height of each gable triangle. Subtract roughly 21 square feet per door, 15 per window and 112 per two-car garage door. That is your paintable wall area.
Do I need two coats of exterior paint?
Usually. Sherwin-Williams’ Duration data sheet allows one coat when repainting over sound paint and calls for two on new, bare surfaces. A color change, heavy chalking, sun-faded south and west walls, and spot-primed repairs all look patchy with one coat, so most professional exteriors on the Front Range get two.
How much elastomeric paint do I need for stucco?
Sherwin-Williams lists its ConFlex SherLastic elastomeric at 115 to 160 square feet per gallon for a two-coat system, or 60 to 80 for one heavy coat. A house with 2,000 square feet of stucco needs roughly 13 to 17 gallons for the two-coat system. Rough textures land at the low end of the coverage range.
How much paint do I need for exterior trim?
Multiply the linear feet of trim by its width in inches and divide by 12. Most houses come out to 200 to 300 square feet of trim, which is about 1.5 to 2.2 gallons for two coats at 275 square feet per gallon. Deep soffits, wide fascia and decorative trim add more, so measure those separately.
Is it better to buy too much exterior paint or too little?
Too much. Running out halfway up a wall means stopping mid-coat, and a second batch can differ slightly in color. Buy for the low end of the coverage range, box the paint so every container matches, keep a quart for touch-ups, and take the rest to a Colorado PaintCare drop-off site.
Sources
Coverage figures and costs come from the documents listed; house-size figures are our arithmetic from them. Checked October 25, 2026.
- Duration Exterior Acrylic Flat, K32 Series, product data sheet, Sherwin-Williams, 08/2020 (public copy filed with the City of Detroit): coverage 250–300 sq ft per gallon, one coat on repaints and two on bare surfaces, stucco cure time.
- Elastomeric product guide, Sherwin-Williams: ConFlex SherLastic 115–160 sq ft per gallon as a two-coat system, 60–80 as a one-coat system, 24-hour recoat.
- How much does it cost to paint a house exterior in Denver, CO?, Angi, updated November 13, 2025: $1.55–$4.10 per sq ft, average $3,250, labor $26–$102 per hour per painter.
- Colorado paint recycling and drop-off locations, PaintCare: no-charge drop-off for leftover paint.
Rather have it measured for you?
Send photos of each side of the house and we will send back a written estimate with the paint, the preparation and the schedule spelled out. Or we can come measure in person. Both are free.
Prefer to talk it through? 720-208-5645