How much paint do I need?
The amount of paint you need depends on the surface area being painted,
the number of coats, the paint's coverage rate, and the condition and
texture of the surface. This paint calculator estimates the required
gallons based on the dimensions and coverage information you provide.
How the paint calculator works
For walls, the calculator estimates wall area from the room length,
width, and wall height. Doors and windows can be subtracted from the
wall area when their dimensions are provided. Ceilings and trim can
also be calculated separately.
The estimate accounts for the number of coats and adjusts effective
coverage for textured surfaces. Multiple rooms can be added to calculate
the total paint required for an entire project.
Paint coverage and gallons
A common planning figure is approximately 400 square feet per gallon,
but actual coverage varies by product and surface. For the most accurate
estimate, enter the coverage rate listed by the paint manufacturer.
Interior vs. exterior paint
Interior and exterior painting projects can have different coverage
requirements because surfaces, textures, materials, weather exposure,
and application conditions vary. For exterior projects, this calculator
includes common surface types such as siding, wood, masonry, and stucco.
Primer and paint coats
Primer may be useful on new, porous, repaired, stained, or dramatically
different surfaces. Add primer to the estimate when needed and enter
the coverage rate and number of coats recommended for your product.
How to get the most accurate paint estimate
The best estimates are available using information from a Product Data
Sheet or similar document, if available. Manufacturer coverage rates
should take precedence over general rules of thumb when they are
available for the specific paint or primer you plan to use.
Actual paint requirements may vary based on surface condition, texture,
application method, number of coats, paint color, substrate, and other
project-specific factors. Consider rounding your purchase up rather
than relying on an estimate that leaves no allowance for waste or
future touch-ups.
Paint Calculator FAQ
How many gallons of paint do I need for a room?
It depends on the room dimensions, wall height, number of coats, and
paint coverage. Measure the walls and enter those dimensions into the
calculator for an estimate.
Does the paint calculator account for doors and windows?
Yes. You can enter the number and dimensions of doors and windows so
their area can be removed from the wall area before calculating paint.
Does the calculator include multiple coats?
Yes. Wall, ceiling, trim, and primer coats can be specified separately.
The calculator multiplies the applicable surface area by the number of
coats before applying the coverage rate.
Does textured wall paint require more paint?
Textured surfaces can require more paint because their effective
coverage can be lower than a smooth surface. The calculator allows you
to select a texture level or enter a product-specific coverage rate.
Should I use the coverage listed on the paint can?
Yes. Manufacturer coverage information is generally more useful for
estimating a specific product than a generic square-foot-per-gallon
assumption.
Estimate:
This calculator provides an approximate estimate of the amount of paint
needed. For the most accurate estimate, use the coverage rate and other
relevant information provided in the manufacturer's Product Data Sheet
(PDS) or a similar product document, when available. Actual paint
requirements may vary based on surface condition, texture, application
method, number of coats, and other project-specific factors.