Use this tool to easily calculate how much paint you need to cover your interior walls based on square footage.

## Interior Paint Calculator

Use this calculator to determine the total square footage of wall space that requires paint. Please ensure all dimensions are in feet and input all required values.

### How to Use the Calculator:

- Enter the length of the room in feet.
- Enter the width of the room in feet.
- Enter the height of the room in feet.
- Enter the number of doors in the room.
- Enter the number of windows in the room.
- Click the “Calculate” button to get the result.

### How the Calculation Works:

The calculator computes the total wall area by calculating the area of each wall and then summing these areas. It subtracts the area occupied by doors and windows to give the final paintable surface area. The average sizes used are 21 square feet for each door (3ft x 7ft) and 12 square feet for each window (3ft x 4ft).

### Limitations:

This calculator provides an estimate based on average door and window sizes. For custom-sized doors and windows or rooms with unusual shapes, the actual area may vary.

## Use Cases for This Calculator

### Calculate Total Square Feet for Walls

Enter the length and height of each wall, excluding windows and doors. The calculator will add up the square footage for all walls. This helps you estimate the total paint needed for the walls.

### Estimate Square Feet for Ceiling

Measure the length and width of the ceiling area. Input these dimensions into the calculator to determine the square footage of the ceiling. This is vital for estimating the amount of paint required to paint the ceiling.

### Deduct Windows and Doors Area

Measure the width and height of windows and doors on each wall. Input these dimensions into the calculator to subtract the square footage from the total walls area. This gives a more accurate paint estimation.

### Calculate Primer Requirement

Input the total square footage of walls and ceiling to determine the amount of primer needed. The calculator accounts for the surface area to ensure you have sufficient primer for sealing the walls before painting.

### Estimate Paint Quantity for Walls

Based on the total square footage of walls, input the coverage area of paint per gallon. The calculator will divide the wall area by the paint coverage to give you the number of gallons necessary for painting.

### Compute Paint Amount for Ceiling

Using the square footage of the ceiling and the paint coverage per gallon, input the details into the calculator. The result will show the quantity of paint required to coat the ceiling evenly.

### Account for Coat Layers

Factor in the number of coats needed for the walls and ceiling for a quality finish. Enter the total square footage, coverage per gallon, and the number of coats desired to find out the total paint quantity required.

### Adjust for Overspray and Wastage

Consider the overspray and paint wastage during application. The calculator provides an option to adjust the estimated paint quantity for incidental losses, ensuring you have enough paint for the project.

### Calculate Total Paint Cost

Input the price per gallon of paint to determine the total cost of paint required for the project. The calculator multiplies the paint quantity by the price to give you an accurate budget estimate for painting.

### Save and Print Results

After calculating the paint requirements and costs, you can choose to save or print the results for future reference. The option allows you to keep track of the estimates and easily share them with others involved in the project.