A clearer estimate for sloped ceilings

Vaulted ceiling
paint calculator

Use the slope you actually have—not just the floor footprint. Enter each side’s horizontal run and rise to estimate paintable area, coats, coverage, and gallons.

Estimate my ceiling

Measure horizontal run and vertical rise separately.

THE ESTIMATOR

Measure your surfaces

Use feet and square feet. Measure the horizontal run—not the sloped board length.

01 Vaulted ceiling shape

Room length ftLength along the ridge Left horizontal run ftEave to ridge, horizontally Left rise ftTop of wall to ridge Right horizontal run ftEave to ridge, horizontally Right rise ftTop of wall to ridge Ceiling openings sq ft totalFor example, skylights

02 Coats and product coverage

Ceiling coats Coverage sq ft / galCheck your product label Extra allowance %Optional; set your own

The 350 sq ft/gal starting value is an editable planning placeholder, not a product promise. Coverage varies by paint and surface. One BEHR ceiling-paint data sheet lists 250–400 sq ft/gal and excludes spray loss; use the rate for your own paint.

03 Optional wall surfaces Add side walls or gable endsEstimate wall paint separately from ceiling paint.

01 / UNDERSTAND THE SHAPE

Run is not slope length.

A vaulted ceiling has more surface than its floor footprint. Each side becomes a right triangle; its slope length is multiplied by room length.

A two-plane cross-section. Each side can use different run and rise values.

02 / SHOW THE FORMULA

Each slope√(run² + rise²)

Ceiling arearoom length × (left + right slope)

Paint gallonspaintable area × coats ÷ coverage

Opening deductions and any optional allowance are shown explicitly. No hidden vaulted-ceiling multiplier is applied.

Keep products separate

Ceiling and wall paint can have different coverage rates. If you add walls, the calculator reports those gallons separately.

Use the can’s coverage rate

Coverage changes with product, surface porosity, texture, and application method. Check technical data for your specific paint.

METHOD & SOURCES

Measure, calculate, then verify.

The geometry uses the Pythagorean theorem for each sloped plane. Paint quantity is paintable area × coats ÷ product coverage. This is an estimate, not a paint specification or purchase guarantee.

BEHR ULTRA Interior Ceiling Paint technical data sheet — one product example lists 250–400 sq ft/gal depending on application and substrate porosity; spray loss is excluded.
Watt & Wall: vaulted-ceiling paint quantity guide — a worked example of slope-area and paint calculations.
BEHR PRO Coverage Calculator — its visible form includes a vaulted-ceiling option; this estimator instead exposes geometric inputs and math.

Sources checked October 14, 2026. Product rates and directions can change; check the label for your paint.

QUICK ANSWERS

Vaulted ceiling paint questions

How do I estimate paint for a vaulted ceiling?

Measure room length, then the horizontal run and vertical rise for each roof plane. Calculate each slope length with √(run² + rise²), add both lengths, and multiply by room length. Subtract openings, multiply by coats, then divide by your paint’s stated coverage per gallon.

Why is ceiling area larger than the room footprint?

The floor footprint uses horizontal width, but the painted surface follows the longer sloped planes. The difference depends on rise and run; one fixed percentage cannot represent every shape.

What if the two sides are not symmetrical?

Enter separate left and right runs and rises. Each side is calculated independently, without a symmetry assumption.

Does this include waste, primer, or spray loss?

No hidden waste factor is included. You can enter your own optional allowance. Primer and spray loss are not automatically added; follow the product instructions and application method.

Can this handle dormers, beams, or a flat center section?

This version models two straight roof planes meeting at one ridge. Measure additional surfaces separately; do not force dormers, exposed beams, or a flat ridge section into the two-plane model.

All results are estimates for planning. Confirm dimensions and product coverage with the manufacturer. For high or hard-to-reach surfaces, use safe access practices and get help measuring when needed.