Paint cost calculator

How to use the paint cost calculator

Estimate paint, primer, supplies, and optional professional labor for a room. Enter room measurements, paint prices, coverage, and labor settings to get material and project totals.

1. Choose Feet or Metres under Units.
2. Enter the room length, width, height, number of doors, windows, and finish coats.
3. Turn on ceiling, trim, primer, or professional labor when they apply to your project.
4. Enter paint, primer, supplies, and labor prices. Open the advanced options to adjust coverage, opening sizes, or trim measurements.
5. Review the grand total, material total, labor estimate, cost per area, and detailed quantity breakdown.

What to enter

Units

Choose Feet for ft, sq ft, and gal, or Metres for m, m², and L. The default is Feet.

Room length

Room length. The default is 12 ft in imperial mode or 12 m in metric mode.

Room width

Room width. The default is 14 ft in imperial mode or 14 m in metric mode.

Wall height

Floor-to-ceiling wall height. The default is 8 ft in imperial mode or 8 m in metric mode.

Coats

Number of finish coats, from 1 to 5. The default is 2.

Doors

Number of doors subtracted from the wall area. The default is 1.

Windows

Number of windows subtracted from the wall area. The default is 2.

Paint the ceiling too

Adds the room length × width as a painted ceiling area. Off by default.

Paint baseboard and trim

Adds trim using the room perimeter unless you enter a different trim length. Off by default.

Add one coat of primer

Adds one primer coat over the walls and, when selected, the ceiling. Off by default.

Paint price

Price per gallon in imperial mode or per litre in metric mode. The default is $45 per unit.

Primer price

Price per gallon in imperial mode or per litre in metric mode. The default is $25 per unit. Shown when primer is selected.

Supplies allowance

Flat allowance for brushes, rollers, tape, and drop cloths. The default is $40.

Include professional labor

Adds labor using the painted area, number of coats, productivity, and hourly rate. Off by default.

Hourly rate

Professional labor rate in dollars per hour. The default is $50 per hour. Shown when labor is selected.

Area per hour per coat

Area completed per hour for each coat. The default is 100 sq ft per hour in imperial mode or 9.3 m² per hour in metric mode. Shown when labor is selected.

Paint coverage

Paint spread rate. The default is 400 sq ft/gal or 9.8 m²/L. Valid coverage is 250–450 sq ft/gal or 6–11 m²/L.

Primer coverage

Primer spread rate. The default is 300 sq ft/gal or 7.4 m²/L. Enter a positive value when primer is selected.

Area per door

Area subtracted for each door. The default is 21 sq ft in imperial mode or 1.95 m² in metric mode.

Area per window

Area subtracted for each window. The default is 15 sq ft in imperial mode or 1.4 m² in metric mode.

Trim length

Linear trim length. The default is the room perimeter when trim is selected. Use ft or m based on Units.

Trim face width

Visible trim width in inches. The default is 4 in, including when metric room measurements are selected.

Example: 12 × 14 ft room with primer and labor

Use the default imperial room measurements: 12 ft length, 14 ft width, 8 ft height, 1 door, 2 windows, and 2 finish coats. Turn on Add one coat of primer and Include professional labor. Leave the ceiling and trim off. Use the default prices: $45/gal paint, $25/gal primer, $40 supplies, and $50/h labor with productivity of 100 sq ft per hour per coat. Perimeter: 2 × (12 + 14) = 52 ft. Gross wall area: 52 × 8 = 416 sq ft. Openings: 1 × 21 = 21 sq ft for the door, and 2 × 15 = 30 sq ft for the windows. Total openings: 21 + 30 = 51 sq ft. Net wall area: 416 − 51 = 365 sq ft. Finish paint: 365 × 2 = 730 sq ft-coats. 730 ÷ 400 = 1.825 gal exact, which rounds to 2 gal to buy. Primer: 365 ÷ 300 = 1.2167 gal exact, which rounds up to 1.25 gal to buy. Finish paint cost: 2 × $45 = $90. Primer cost: 1.25 × $25 = $31.25. Materials: $90 + $31.25 + $40 = $161.25. Labor includes two finish passes and one primer pass: 365 × 2 = 730 sq ft-coats, then 730 + 365 = 1,095 sq ft-coats. Labor hours: 1,095 ÷ 100 = 10.95 h. Labor cost: 10.95 × $50 = $547.50. Grand total: $161.25 + $547.50 = $708.75. Cost per sq ft: $708.75 ÷ 365 = $1.94 after rounding.

How the paint cost is calculated

The calculator first finds the room perimeter with 2 × (length + width). Gross wall area is perimeter × wall height. It subtracts doors × area per door and windows × area per window to get net wall area. If selected, ceiling area is length × width. Trim area is trim length × trim width in inches ÷ 12. Painted area is the sum of walls, ceiling, and trim. Finish paint for each surface is calculated as area × coats ÷ paint coverage. Primer is one coat over the walls and selected ceiling, calculated as wall and ceiling area ÷ primer coverage. Walls, ceiling, trim, and primer are treated as separate products. Exact paint quantities are converted to purchasable quantities. A fractional gallon under one-half gallon is rounded up to quarts; a fractional gallon of one-half or more is rounded up to whole gallons. Five-gallon buckets are suggested when a product reaches 5 gallons. Metric results convert US gallons to litres using 1 gal = 3.78541 L, while can sizes remain US sizes. Material cost uses the rounded finish paint quantity × Paint price, plus the rounded primer quantity × Primer price, plus the Supplies allowance. If professional labor is selected, labor hours are painted area × finish coats, plus one primer pass when selected, divided by Area per hour per coat. Labor cost is labor hours × Hourly rate. The grand total is materials + labor, and the cost per area is the grand total ÷ painted area. Labor hours, costs, totals, and cost per area are rounded to two decimals.

Reading the results

Grand total combines the Materials total with Labor when professional labor is selected. Materials include rounded finish paint, rounded primer when selected, and the supplies allowance. The breakdown shows painted area, paint and primer costs, labor hours, and labor cost. The paint quantity results distinguish exact volume from the amount to buy, which is rounded to available quart or gallon quantities.

Limitations and common mistakes

• Material prices are the values you enter, so the estimate does not replace local prices or professional quotes.
• Labor uses only painted area, coats, productivity, and hourly rate. It does not create a separate task-by-task labor quote.
• Door and window deductions use the entered areas, with defaults of 21 sq ft per door and 15 sq ft per window in imperial mode. Adjust them if your openings differ.
• The calculator does not add a separate waste percentage. Textured or porous surfaces and major color changes may require more paint than the selected coverage suggests. The calculator also rejects inputs when door and window area exceeds gross wall area.

Frequently asked questions