Calculated result
1gallons
Paint purchase
Formula
PAINT-WALL-001Wall length × wall height × coats × (1 + waste) ÷ stated coverage
160 ft²
Wall area
336 ft²
Area across coats + allowance
375 ft² / gallon
Product coverage
Painting calculator
Wall paint calculator
Straight-wall paint coverage, coats, allowance and whole-gallon purchase quantity.
By Feroz Sheikh · Formula PAINT-WALL-001 v1.0.0 · Tested formula
Formula
PAINT-WALL-001v1.0.0Project inputs
Enter your measurements. Switching units converts the same project, including coverage and unit rates. Package yields keep the unit printed beside each field.
Refine measurements and rates at any time. Your current values are included in the material-list PDF.
Planning estimate, not engineering advice. Confirm site measurements and product specifications. Calculation limits.
This calculator converts one rectangular wall, the selected number of coats, product-label coverage and a visible allowance into a whole-gallon paint purchase quantity.
- Measure finished wall length and height.
- Enter the number of finish coats and coverage shown on the selected paint label.
- Keep the allowance visible for touch-ups, cut-ins and actual job conditions before whole-gallon rounding.
Add your project costs
Enter supplier prices and any labour, equipment or delivery costs. Pick a currency — badges, inputs, and totals follow.
Costs use the can rate you type. Construclytic does not fetch paint prices. Primer, ceiling gallons and cut-and-roll labour stay on their own lines. For GCC projects, select QAR, AED, SAR, KWD, OMR or BHD and enter local supplier rates.
How this calculator works
A transparent wall paint calculator takeoff.
Feroz SheikhWritten by Feroz Sheikh · founder
This calculator converts one rectangular wall, the selected number of coats, product-label coverage and a visible allowance into a whole-gallon paint purchase quantity.
PAINT-WALL-001 is a straight-wall takeoff: length × height × coats ÷ labelled coverage, then whole gallons. Doors and windows deduct only if you enter them. It is not a full-room model — that is the interior paint calculator.
Worked example. Example: a 20 ft × 8 ft wall has 160 ft². Two coats with 5% allowance need 336 ft² of coverage; at 375 ft² per gallon, the purchase quantity rounds to 1 gallon.
See the example inputs and calculated result
This separate example uses the calculator's starting values in imperial units. It stays unchanged when you edit the tool above. Example rates, yields and dimensions are assumptions, not recommendations for your project.
| Input | Example value |
|---|---|
| Wall length | 20 ft |
| Wall height | 8 ft |
| Number of coats | 2 count |
| Coverage per gallon | 375 ft² / US gal |
| Waste factor | 5 % |
Example result: Paint purchase — 1 gallons.
Wall length × wall height × coats × (1 + waste) ÷ stated coverage
Use the labelled units above when reproducing this example. To work in metric, switch the calculator to Metric; applicable measurements are converted, while product-specific units remain labelled.
- 1. Measure finished wall length and height.
- 2. Enter the number of finish coats and coverage shown on the selected paint label.
- 3. Keep the allowance visible for touch-ups, cut-ins and actual job conditions before whole-gallon rounding.
Field notes that change the number
- Use the wall that will actually be painted, not the room perimeter unless every wall is in scope.
- Coverage is the label, not a universal 400 ft². Primer and finish do not share a gallon.
- Two coats on new drywall is a different order than one coat on a similar colour.
Common mistakes
- Using room floor area as wall area.
- Skipping coats.
- Folding ceiling paint into this wall count.
Need the broader workflow? Read the painting planning guide.
How-to: How much ceiling paint: area, coats and sloped surfaces · How to estimate interior paint
Questions
Questions about wall paint calculator
Does this deduct doors or windows?
This straight-wall tool does not deduct openings. Use the room paint calculator or subtract significant openings deliberately.
Is one gallon always enough for 375 ft²?
No. Product coverage, surface condition, color change and application method affect actual coverage. Use the product label and field judgment.
What is the formula ID?
This wall paint calculator publishes formula PAINT-WALL-001, version 1.0.0. The ID stays on the result and on the estimate line.