Enter your wall square footage and number of coats. Get gallons rounded to real bucket sizes, instantly.
Your gallon count and bucket breakdown will appear here instantly.
Paint coverage is rated at 350 sq ft per gallon per coat under normal conditions. That is the standard most interior latex paints use, and it is what this calculator assumes.
Two coats is the standard for a repaint. One coat rarely covers evenly, especially over a fresh drywall patch or a color that has faded. Two coats gives a consistent finish and is what most clients expect.
Note on primer: if the surface needs primer, that is a separate gallon count. Primer coverage runs around 300 sq ft per gallon. This calculator covers topcoat paint only.
Dark to light adds a coat. Going from a deep navy or forest green to an off-white almost always requires an extra coat to fully block the underlying color. This calculator adds one coat automatically when you toggle that on.
The formula: wall sqft x coats / 350 = gallons, rounded up to a whole number. Minimum one gallon. When you hit four gallons or more, a 5-gallon bucket is cheaper per gallon than buying singles.
When to reach for a 5-gal vs. singles. At 4 gallons and up, a 5-gal bucket is almost always the better buy.
| Gallons needed | Buy this | Notes |
|---|---|---|
| 1 | 1-gal can | Small accent walls, touch-ups |
| 2 | 2 x 1-gal cans | Single small room, one coat |
| 3 | 3 x 1-gal cans | Single room, 2 coats |
| 4 | 1 x 5-gal bucket | Use a 5-gal. Cheapest per gallon. |
| 5 | 1 x 5-gal bucket | Still just one 5-gal bucket |
| 6 | 1 x 5-gal + 1 x 1-gal | One 5-gal, one extra can |
| 10 | 2 x 5-gal buckets | Full room repaint, 2 coats |
The calculator rounds to the nearest whole gallon and prefers 5-gal buckets at 4 gallons or more.
Once you have your gallon count, the repaint pricing cheat sheet has the full labor and margin math on one page. For a complete estimate with rooms, paint costs, and labor hours, use the free painting job estimator. To understand how to set your prices from the ground up, read how to price a repaint.
Rollr does the coverage math for you on-site, then turns it into a branded PDF quote you can send before you leave the driveway.
One page of repaint math for the truck: sqft, gallons, labor, margin.
Crew-hours and labor cost from room count, prep level, and day rate.
A clean repaint quote layout you can copy. PDF download, no signup.