Paint calculator
Wall area minus doors/windows → gallons at your coverage rate and coats.
Runs in this tab. The file stays here.
Paint needed
1.82
gallons · 317 sq ft walls
This runs in your browser. Nothing is uploaded.
About Paint calculator
Estimate gallons from room dimensions, door and window area, coats, and coverage rate.
This paint calculator stays in the tab. Nothing is uploaded to ihateonlinetools.com for the calculation. That is the same offline promise as the rest of the site: your numbers, caption, or recipe never need to sit in a third-party form log.
Wall area is perimeter times height minus door and window area you enter. Gallons equal wall area times coats divided by coverage. The default coverage is about three hundred fifty square feet per gallon per coat—check your paint can.
Rooms that are not rectangles still need you to approximate. The page does not invent a floor plan from a photo. Related tools on this site cover nearby jobs without forcing a signup wall.
How to use Paint calculator
- 1Open /home/paint-calculator/ and check the side-panel defaults.
- 2Enter your values or paste your list; the main pane updates.
- 3Copy the result if you need it elsewhere. Closing the tab clears local state unless noted.
What it won't do
- Not professional advice and not a hosted account product.
- Garbage in, garbage out: wrong inputs yield wrong outputs.
Common questions
Does paint calculator upload anything?
No. Inputs and outputs stay in the browser process. Sharing features that exist, such as countdown links, only put values you choose into the URL on your device.
What formula or method does paint calculator use?
Wall area is perimeter times height minus door and window area you enter. Gallons equal wall area times coats divided by coverage. The default coverage is about three hundred fifty square feet per gallon per coat—check your paint can.
When should I not rely on paint calculator alone?
When a clinician, building code, platform policy, or teacher requires a signed process. This page is a calculator and explainer, not a certificate.
Is paint calculator free and offline-capable?
Yes. After the static page loads, the logic runs without calling an external compute API. Return visits may use the service worker cache for the shell.
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Why this one doesn't upload your file
There is no server to upload to. This page is a static file, and the work happens in your browser using the same graphics and WebAssembly code that renders every other site you visit. Your file is read from disk into memory, processed, and handed back as a download. Once the page has loaded you can disconnect from the network entirely and it keeps working. The longer explanation