How Much Paint Do I Need for My House? | Complete Guide

cost to paint interior of house

Painting your home can increase its value. The hard part is knowing how much paint to buy. Buying too little means extra trips to the store. Buying too much leaves you with leftover cans. Plan ahead, measure carefully, and learn about paint application for the best results.

In this blog post, we will help you calculate how much paint you need for cabinets, walls, ceilings, or doors. It also shows how to factor in surface textures, number of coats, and primers for professional results. Let’s get started!

Knowing Paint Coverage

To calculate cost of painting a house, it’s essential to know how much paint a container can cover before purchasing. The amount of paint that will cover a surface depends on the type of surface, quality and number of coats.

Standard Coverage Estimates:

  • Interior walls: The interior walls of a smooth surface can be painted with 1 gallon. This covers a space between 350 and 400 sq. ft.
  • Trim and Doors: Use 1 gallon of paint per 8 gallons of wall paint.
  • Ceilings: 1 Gallon per 350 sq. ft. (may differ by texture).
  • Exterior Walls: 1 Gallon per 250 to 400 sq. ft., depending on roughness

Measure your home accurately

Accurate measurements are key to a successful painting project. Here is how you measure different surfaces:

The interior walls:

  • For each wall, measure the height and width.
  • To calculate the total square footage of all walls, add up their dimensions.
  • Remove the areas around windows and doors.
  • Average door: 20 sq ft

Average window: 12-15 sq ft

Ceilings:

  • Multiply the length by the width.
  • For example: 11ft by 15ft is 165 square feet (sq ft) – 0.5 gallon for one coat.

Glass and  Doors:

  • Multiply the height by the width.
  • For example: Two 20-square-foot doors = 40 square feet
  • Double the amount of paint required if you are painting on both sides, or if your color is bold.

Trim and Baseboards:

  • Measure linear length x width (in feet).
  • In general, 8 gallons of wall paint will cover 1 gallon of trim and gutters.

You cam also use a paint estimator for the paint quantity and can ensure you are buying the right amount of paint for your house.

Exterior House Paint

Exterior painting requires extra considerations:

To estimate paint for gables, measure the area, then multiply by the gable height (excluding the base).

  1. To calculate the gables, multiply width x Height / 2.
  2. Remove windows and doors.
  3. If the surface is rough, increase the amount of paint you need. This applies to brick, stucco, or wood siding.

Example:

For a 2000 square foot exterior house, you will need 10 gallons to paint two coats.

Coats and Primers

It is important to apply multiple coats in order to achieve a high-quality finish. Let’s discuss how many coats of paint you’ll need.

  • Use a single coat for small touch-ups or colors that are similar.
  • Most interior and exterior projects require two coats.
  • If you want to make a dramatic change in color or if your colors are very dark, it is necessary to apply three coats.

Using Primers:

  • Primer seals surfaces and stops paint from soaking in. It also lowers the number of top coats you need.
  • If you want to make drastic changes in color, use a colored primer.
  • Gray-tinted primer can reduce the number of coats from three to two.

Primer is also a great way to conceal imperfections on rough surfaces or walls.

Estimated Paint Costs for Cabinets and Furniture

Precision is required when painting cabinets, shelves or tables.

  • Estimate 10-20% extra paint for detailed projects.
  • For a smooth finish, use high-quality brushes and foam rollers.
  • It is better to wear multiple thin coats than one thick coat.

Use Paint Calculators

Online paint calculators simplify your life:

  • Enter the room size, type of surface, number and coverage of paint coats.
  • Popular options: BEHR Paint Calculator, Sherwin-Williams, Benjamin Moore, Dulux.
  • Compare calculator calculations with manual calculations to ensure accuracy.

Tools and Techniques For A Professional Finish

Use the right tools and techniques for a professional finish. For large projects, use airless sprayers or brushes and rollers that fit the paint and surface. Always prepare surfaces by cleaning, sanding, filling cracks, and taping edges. Paint using ‘W’ or ‘M’ patterns. Lightly sand between coats.

Accent spaces and small rooms

Painting small rooms and transitional areas like halls or entryways requires a customized approach. It is often easier to use quarts of paint than gallons. Also, bolder colors make an impact even if they require more coats. Be sure to measure the wall, including windows, doorways, and textured surfaces. Accent walls allow you to try out different colors and textures on just one wall. You can experiment by using less paint but still ensuring that the entire surface is covered.

Conclusion

It’s not difficult to determine how much paint is needed. You can purchase enough paint to complete any project by measuring the walls, ceilings and trims. Then, add windows and doors and subtract them. Online calculators can provide additional assistance. Invest in high-quality tools and use proper application and preparation techniques. 

Whether painting a single room, your entire interior, or your home’s exterior, careful planning ensures a professional-looking, durable finish that transforms your space and makes your home shine.