Calculated result
2gallons
Exterior paint gallons
Formula
PAINT-EXT-001(wall length × height − openings) × coats × (1 + waste) ÷ coverage
360 ft²
Gross wall area
228 ft²
Paintable area
501.6 ft²
Area across coats + waste
Painting calculator
Exterior paint calculator
a 40 × 9 ft elevation with two doors and six windows, two coats at 350 ft²/gal with 10% waste rounds to 2 gallons. In metric, gross wall area is 33.45 m².
Formula. (wall length × height − openings) × coats × (1 + waste) ÷ coverage
Exterior-paint gallons from wall length, height, openings, coats and labelled coverage. Interior rooms use the paint calculator.
By Feroz Sheikh · Formula PAINT-EXT-001 v1.0.0 · Tested formula
Formula
PAINT-EXT-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.
Exterior wall length times height, minus door and window openings, times coats, divided by labelled exterior coverage after waste.
- Measure each elevation. Measure gables separately as base × vertical height ÷ 2. On a separate takeoff, enter half the base as wall length, the gable height and measured openings; keep waste separate.
- Exterior coverage is not interior coverage. Use the can you will roll outside.
- Trim paint is the trim calculator.
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 exterior paint takeoff.
Feroz SheikhWritten and reviewed by Feroz Sheikh · founder
Exterior wall length times height, minus door and window openings, times coats, divided by labelled exterior coverage after waste.
PAINT-EXT-001 is a straight elevation after openings, two coats at 350 ft²/gal. Interior paint uses a room perimeter. Measure gables separately as base × vertical height ÷ 2. On a separate takeoff, enter half the base as wall length, the gable height and measured openings; keep waste separate. Trim enamel is the trim calculator.
A listed house size is a floor area
Floor area, perimeter and wall height are different measurements. Example gallons for 1,000 to 3,000 sq ft houses, on one storey and two, are in exterior paint gallons by house size. A 2,000 sq ft two-storey example on that page is 17 US gallons for two coats at 250 sq ft per gallon. Measuring one elevation, including a gable, is the exterior paint quote calculator.
Worked example. Example: a 40 × 9 ft elevation with two doors and six windows, two coats at 350 ft²/gal with 10% waste rounds to 2 gallons.
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 | 40 ft |
| Wall height | 9 ft |
| Doors | 2 count |
| Windows | 6 count |
| Door deduction | 21 ft² |
| Window deduction | 15 ft² |
| Number of coats | 2 count |
| Coverage per gallon | 350 ft² / US gal |
| Waste factor | 10 % |
Example result: Exterior paint gallons — 2 gallons.
(wall length × height − openings) × coats × (1 + waste) ÷ 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 each elevation. Measure gables separately as base × vertical height ÷ 2. On a separate takeoff, enter half the base as wall length, the gable height and measured openings; keep waste separate.
- 2. Exterior coverage is not interior coverage. Use the can you will roll outside.
- 3. Trim paint is the trim calculator.
Field notes that change the number
- Measure each elevation to the eave. Do not average a two-storey wall with a porch beam.
- Exterior coverage is not interior coverage. Masonry and wood do not share a number.
- Trim, soffit and doors as slabs are companion lines.
Common mistakes
- Using the interior room calculator on an elevation.
- Ignoring gables, then inflating waste to guess them.
- Folding primer and finish into one exterior can count.
Gulf exterior work is often masonry or render. Replace the default coverage with the labelled exterior product; do not keep a US wood-siding figure.
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 to stain a wood fence · Exterior paint quote calculator from wall area
Questions
Questions about exterior paint
Is this the interior paint calculator?
No. Interior paint uses a room perimeter. This page is a straight elevation after openings.
Masonry or wood?
Coverage changes with texture. Replace the default with the labelled exterior product.
What is the formula ID?
This exterior paint calculator publishes formula PAINT-EXT-001, version 1.0.0. The ID stays on the result and on the estimate line.