How the paint cost calculator works
The calculator first works out how many whole gallons to buy, exactly like the paint calculator, then multiplies by your price and adds supplies such as rollers, tape, and drop cloths.
The chart separates the paint that goes on the wall from the allowance and leftover you pay for by buying whole cans, which shows when a different can size might save money.
Formula and assumptions
- price
- your shelf price per gallon (or per litre in metric)
- supplies
- optional lump sum for tools and consumables
Assumptions and limits
- Prices are your inputs; the default is an example only.
- Materials only. No labor, tax, or delivery.
Worked example
The same 12 × 10 ft room, two coats, and an example price of $42 per gallon.
- The paint estimate rounds to 3 gallons.
- 3 × $42 = $126.00 of paint.
- No supplies entered, so the total is $126.00.
These are the calculator’s default values, so the live result above matches this example until you change an input.
How to measure correctly
- Use the price for the size you will buy; per-gallon prices differ between quarts, gallons, and five-gallon buckets.
- Price primer separately if the walls need it.
- Add sales tax and delivery after the estimate.
Paint Cost Calculator FAQ
How much does it cost to paint a room?
For DIY, it is the paint you buy plus supplies. The answer depends entirely on the room size, coats, and the paint you choose, which is why this tool uses your price rather than a national average.
Is a five-gallon bucket cheaper than single gallons?
Often per gallon, but not always per project. If you need 3 gallons, a 5-gallon bucket may leave 2 unused. Compare the total for each option with your actual prices.
What supplies should I budget for?
Rollers and covers, brushes, a tray, painter’s tape, drop cloths, patching compound, and sandpaper are typical. Enter them as one lump sum.
Does the cost include primer?
No. Estimate primer separately with the primer calculator and add it as supplies or a second budget line.
Why is cost per square foot useful?
It lets you compare rooms and products. A premium paint that covers in fewer coats can cost less per square foot than a cheaper one that needs an extra coat.
Does it include labor?
No. This is a material budget. Painting contractors price labor in their own ways, so add a quote separately.