Calculated result
2gallons
Primer gallons
Formula
PAINT-PRIMER-001(2 × (L + W) × H − openings) × coats × (1 + waste) ÷ primer coverage
448 ft²
Gross wall area
413 ft²
Paintable area
454.3 ft²
Area across coats + waste
Painting calculator
Paint primer calculator
a 16 × 12 × 8 ft room, one door and one window, one coat at 300 ft²/gal with 10% waste rounds to 2 gallons of primer. In metric, gross wall area is 41.62 m².
Formula. (2 × (L + W) × H − openings) × coats × (1 + waste) ÷ primer coverage
Primer gallons from room walls, openings, coats and labelled primer coverage. Finish paint is a different tool.
By Feroz Sheikh · Formula PAINT-PRIMER-001 v1.0.0 · Tested formula
Formula
PAINT-PRIMER-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.
Room walls use 2 × (length + width) × height, minus openings, times primer coats, divided by labelled primer coverage after waste.
- Measure the room the same way as the interior paint calculator.
- Primer coverage is usually lower than finish paint. Use the primer can, not the topcoat label.
- Finish paint stays the paint calculator. Ceilings stay the ceiling tool.
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 paint primer takeoff.
Feroz SheikhWritten and reviewed by Feroz Sheikh · founder
Room walls use 2 × (length + width) × height, minus openings, times primer coats, divided by labelled primer coverage after waste.
PAINT-PRIMER-001 primes room walls at one coat and 300 ft²/gal with a visible waste field. Interior finish paint is two coats at 375 ft²/gal and no waste on that page. Folding primer into finish paint hides a can and the wrong coverage.
Worked example. Example: a 16 × 12 × 8 ft room, one door and one window, one coat at 300 ft²/gal with 10% waste rounds to 2 gallons of primer.
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 |
|---|---|
| Room length | 16 ft |
| Room width | 12 ft |
| Ceiling height | 8 ft |
| Doors | 1 count |
| Windows | 1 count |
| Door deduction | 20 ft² |
| Window deduction | 15 ft² |
| Primer coats | 1 count |
| Coverage per gallon | 300 ft² / US gal |
| Waste factor | 10 % |
Example result: Primer gallons — 2 gallons.
(2 × (L + W) × H − openings) × coats × (1 + waste) ÷ primer 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 the room the same way as the interior paint calculator.
- 2. Primer coverage is usually lower than finish paint. Use the primer can, not the topcoat label.
- 3. Finish paint stays the paint calculator. Ceilings stay the ceiling tool.
Field notes that change the number
- Measure the room the same way as the interior paint calculator: 2 × (L + W) × H minus openings.
- Primer coverage is usually lower than finish paint. Use the primer can, not the topcoat label.
- Ceilings stay the ceiling tool at one coat. Finish paint stays the paint calculator.
Common mistakes
- Using finish-paint coverage for primer.
- Priming the lid on this page and missing the ceiling takeoff.
- Skipping waste on a textured or new-drywall room.
Need the broader workflow? Read the painting planning guide.
How-to: How many gallons of exterior paint for a 1,500, 2,000 or 2,500 sq ft house · How many litres of paint per m² · Joint compound quantity: gallons, pails and finishing scope · How much ceiling paint: area, coats and sloped surfaces · Exterior paint quote calculator from wall area
Questions
Questions about paint primer
Why is primer its own page?
Because the coverage, coat count and SKU are different. Folding primer into finish paint hides a can.
Does this include the ceiling?
No. Prime the lid with the ceiling calculator at one coat, or add that area as a second line.
What is the formula ID?
This paint primer calculator publishes formula PAINT-PRIMER-001, version 1.0.0. The ID stays on the result and on the estimate line.