Paint Coverage Calculator

Calculate Paint Coverage and Quantity

Stop guessing how much paint you need! This calculator helps you buy the right amount of paint for your project - no waste, no extra trips to the store.

How Much Paint Do You Need?

The calculator determines:

• Liters needed: For metric measurements
• Gallons needed: For US measurements
• Accounts for multiple coats
• Adjusts for paint coverage rates

Standard Paint Coverage

Typical Coverage Rates:

• 1 gallon covers 350-400 sq ft (one coat)
• 1 liter covers 10-12 sq meters (one coat)
• Premium paints: Better coverage
• Cheap paints: May need more coats

Factors Affecting Coverage:

• Surface texture (smooth vs. rough)
• Surface porosity (drywall vs. wood)
• Paint quality
• Application method
• Color change (dark to light = more coats)

Calculating Wall Area

Simple Room Formula: Wall Area = (Room Perimeter) × (Wall Height)

Example: 12 ft × 15 ft room, 8 ft ceiling

• Perimeter: (12 + 15 + 12 + 15) = 54 ft
• Wall Area: 54 × 8 = 432 sq ft
• For one coat: ~1.2 gallons needed

Don't Forget to Subtract:

• Doors: ~20 sq ft each
• Windows: 15-20 sq ft each
• Built-ins and cabinets

How Many Coats?

General Guidelines:

• 1 coat: Touch-ups, same color
• 2 coats: Standard for most projects
• 3 coats: Dark to light, dramatic color change
• Primer + 2 coats: New drywall, stains, repairs

Color Changes:

• Light to light: 2 coats
• Light to dark: 2 coats
• Dark to light: Primer + 2-3 coats
• Dark to dark (different shade): 2-3 coats

Types of Paint

Interior Paint:

• Flat/Matte: Hides imperfections, hard to clean
• Eggshell: Slight sheen, easier to clean
• Satin: Durable, good for high-traffic areas
• Semi-gloss: Kitchen, bathroom, trim
• Gloss: Doors, cabinets, furniture

Exterior Paint:

• Flat: Good for siding
• Satin/Eggshell: Most exterior walls
• Semi-gloss/Gloss: Trim, doors, shutters

Buying Paint

How Paint is Sold:

• Sample: 8 oz (test colors)
• Quart: 32 oz (small projects)
• Gallon: 128 oz (most common)
• 5-gallon bucket: Best value for large jobs

Typical Costs (per gallon):

• Budget paint: $15-25
• Mid-grade: $30-45
• Premium: $50-80
• Designer brands: $80-120+

Application Methods

Brush:

• Best for: Trim, edges, detail work
• Coverage: Slowest
• Finish: Can show brush marks

Roller:

• Best for: Large flat surfaces (walls, ceilings)
• Coverage: Fast and efficient
• Finish: Smooth with right nap

Sprayer:

• Best for: Large projects, exterior, cabinets
• Coverage: Fastest
• Requires: More prep and skill

Primer Basics

When You Need Primer:

• New drywall or wood
• Covering stains (water, smoke, marker)
• Dramatic color changes
• Porous surfaces
• Previously unpainted surfaces

Primer Coverage:

• Similar to paint: 350-400 sq ft/gallon
• Usually just one coat needed
• Some paints include primer (2-in-1)

Surface Preparation

Smooth Surfaces (drywall, previously painted):

• Coverage: 400 sq ft/gallon
• Texture: Minimal
• Coats needed: Usually 2

Textured Surfaces (stucco, rough wood):

• Coverage: 250-300 sq ft/gallon
• Texture: Absorbs more paint
• Coats needed: 2-3

Porous Surfaces (raw wood, brick, concrete):

• Coverage: 200-300 sq ft/gallon
• Absorption: High
• May need primer + 2 coats

Ceiling Paint

Ceiling-Specific Considerations:

• Often need flat/matte finish
• Usually white or off-white
• Splatter and drip issues
• Coverage: 350-400 sq ft/gallon

Ceiling Area Calculation: Simply Length × Width of room

Exterior Projects

Exterior Walls:

• Calculate: (Perimeter × Height) - (Windows + Doors)
• Weather exposure affects paint needs
• Texture (stucco, wood siding) uses more paint

Coverage Adjustments:

• Smooth siding: 400 sq ft/gallon
• Wood lap siding: 300-350 sq ft/gallon
• Stucco: 200-300 sq ft/gallon
• Brick: 150-250 sq ft/gallon

Pro Tips

Buy Extra:

• Add 10-15% for waste and touch-ups
• Keep leftovers for future repairs
• Touch-ups from new cans may not match

Batch Matters:

• Buy all paint from same batch
• Colors can vary slightly between batches
• "Boxing" paint: Mix cans together for consistency

Store Properly:

• Seal can tightly
• Store in cool, dry place
• Lasts 2-10 years if sealed properly
• Label with room and date

Common Room Sizes

Average Paint Needs (2 coats, walls only):

• Small bedroom (10×10): 2 gallons
• Medium bedroom (12×15): 2-3 gallons
• Large bedroom (15×20): 3-4 gallons
• Living room (15×20): 3-4 gallons
• Kitchen (12×15): 2-3 gallons (less due to cabinets)

Time Estimates

How Long Does It Take?:

• Small room: 2-4 hours (one coat)
• Medium room: 4-6 hours (one coat)
• Large room: 6-8 hours (one coat)
• Add 24 hours drying time between coats

Professional vs. DIY:

• Pros work faster (experience + equipment)
• DIY takes 2-3× longer
• But you save $300-500+ on labor!

Money-Saving Tips

1. Buy quality paint: Better coverage = fewer coats
2. Prep properly: Saves paint and looks better
3. Use right tools: Good roller/brush makes difference
4. Correct nap size: Match to your surface
5. Don't thin unnecessarily: Reduces coverage

Mistakes to Avoid

Buying Too Little:

• Multiple store trips waste time
• New batch might not match
• Project takes longer
• Solution: Buy 10-15% extra

Buying Too Much:

• Wasted money
• Storage issues
• Returns may not be accepted (tinted paint)

Wrong Paint Type:

• Flat paint in high-traffic areas
• Exterior paint for interior
• Wrong finish for application

Use this calculator to determine exactly how much paint you need, then add 10% for safety. Your project will go smoothly, and you'll avoid those frustrating extra trips to the hardware store!