01
Enter your room dimensions
Input the length, width, and height of your room. We will instantly calculate the total surface area of all four walls.
Free Paint Calculator:Exactly How Much Paint Do I Need?
Stop guessing your wall space. Enter your room dimensions, subtract doors and windows, and set your price to get an instant, accurate gallon count and total cost estimate. Free, instant, and no signup required.
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Enter your Room Dimensions
Fill in the fields to calculate paints needed
You have your gallon count.But are you sure it’s the right color?
Buying the wrong amount of paint is annoying. But spending your entire weekend rolling two coats of a color that makes your room look dark, tiny, or dated is a nightmare.
Upload a photo of your room and see exactly how that specific paint color looks on your walls—with your exact natural lighting, furniture, and flooring—before you open a single can.
See It in My Room FreeNo credit card · Try free HD render · Instant result
Why estimating paint isnotoriously tricky.
When planning a paint job, most DIYers forget to do the geometry for all four walls combined, or they forget to subtract the massive chunks of square footage taken up by doors and windows.
The result? You buy way too much, leaving expensive $60 gallons of eggshell sitting in your garage for a decade. Or worse, you buy too little, the roller goes dry halfway through your second coat, and you have to make a panicked run to the hardware store in your messy paint clothes.
Our paint calculator handles the perimeter math, automatically subtracts your openings, and multiplies by your required coats to give you the perfect gallon count.
Simple inputs.One exact paint estimate.
02
Subtract your openings
Count your doors and windows. We automatically subtract standard industry dimensions for these so you aren't buying paint for glass and wood.
03
Preview your painted space + set your budget
Instantly see your selected paint color in a realistic AI room render while calculating your required gallons and total estimated cost.
Smart subtraction fordoors and windows
You shouldn't pay for paint you aren't going to use. Standard calculators just multiply length by width, making you overbuy.
By letting you input your Number of windows and doors, our tool automatically deducts that empty space from your total square footage, saving you money.
Shadowed living room
Minimalist Gaming Room
Bathroom
Primary bedroom
Moody bedroom preview
Accurate multi-coat cost estimation
Painting a dark wall white? You'll need primer and two coats. Refreshing a light wall? One coat might do. By letting you adjust the Coats needed and your exact Price per gallon, our result card gives you a highly accurate reality check on your materials budget before you head to the paint mixer.
See the color in your actual roomnot just on a tiny swatch
A 2-inch paper paint swatch under the hardware store's fluorescent lights will look drastically different on your walls at sunset.
Upload a photo of your space, and our AI will render your new paint color into it realistically, in seconds. See the vibe before you commit to the work.
Render My Room Free with DesignSense
Try for free · No credit card · 32+ design styles
DesignSense AI ? Everything You Need to Visualize Your Home Renovation
The paint render is just the start. Here's what?s included in your free account:
Wallpaper Calculator
Estimate wallpaper rolls, coverage, and installation costs
Renovation Cost Calculator
Estimate home renovation costs and project budgets
Touch Up Studio
Fix imperfections and refine interior design images
AI Room Redesign
Upload any room photo and see it transformed in 32+ styles
Homeowners
Plan renovations with photorealistic AI home redesign concepts
Interior Designers
Visualize room transformations and redesign concepts instantly
Common questions, answered
On average, one gallon of premium interior acrylic or latex paint covers between 350 and 400 square feet for a single coat. Our calculator uses a safe average of 360 square feet per gallon to ensure you don't run short.
In most cases, yes. Unless you are painting over the exact same color just to refresh it, two coats provide the best durability, color depth, and even coverage. If you are painting a light color over a dark wall, you may even need a primer plus two coats.
This specific calculation is for walls only. If you want to paint your ceiling, simply multiply your room's Length by its Width to get the ceiling square footage, and divide that number by 360 to find out how many extra gallons you need.
Color is entirely dependent on lighting. A color that looks great in a magazine might look dreary in a north-facing room with small windows. The AI render allows you to test out the paint color in your exact room's lighting conditions before you spend money.
Color is entirely dependent on lighting. A color that looks great in a magazine might look dreary in a north-facing room with small windows. The AI render allows you to test out the paint color in your exact room's lighting conditions before you spend money.
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Midcentury modern
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Modern
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Industrial
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Farmhouse
Minimalist
Gaming Room
Art deco
Halloween
Ski Chalet
Sketch
Scandinavian
Modern
Minimalist