🎨 Estimating how much paint you need sounds simple, but most people either buy too much (wasting money) or run out halfway through the job. Paint cans list coverage numbers, but those rarely match real-world results because walls absorb paint differently, surfaces vary, and multiple coats are often needed.
This guide walks you through everything you need to know about paint coverage and includes a simple calculator to estimate exactly how much paint you need for your project.
Table of Contents
🎯 What This Calculator Tells You
- Total wall area
- Amount of paint needed for 1–2 coats
- Number of gallons or liters required based on typical coverage
- Recommended amount to buy (with margin)
🎨 Paint Coverage Calculator
🧱 How Paint Coverage Works
Paint companies list coverage assuming perfect, smooth, primed walls. Real homes rarely match that.
Typical real-world coverage per gallon:
- Premium paint: 350–400 sq ft
- Standard paint: 250–300 sq ft
- Rough surfaces (stucco, brick): 150–250 sq ft
The calculator defaults to 350 sq ft per gallon, but you can adjust it based on:
- Surface texture
- Primer used
- Paint quality
- Roller efficiency
🔁 How Many Coats Do You Really Need?
Most projects need at least 2 coats, especially when:
- Painting light over dark colors
- Painting new drywall
- Using matte finish
- Using budget paint
One coat only works when:
- You’re touching up
- The paint matches extremely closely
- You’re using a high-end one-coat paint on a light surface
🧱 Do You Need Primer?
Use primer if:
- Switching from dark to light
- Painting bare drywall
- Painting stained or glossy surfaces
- Painting over wood
Primer improves coverage and reduces the number of paint coats needed.
🛠️ How to Measure Wall Area
Wall area formula:
Wall Area = Width × Height
For multiple walls:
Add up each wall’s area.
Example:
Room with four 10 ft × 8 ft walls
= 10×8×4 = 320 sq ft total wall area.
Subtract windows and doors?
Yes, but most pros leave them in.
Extra paint is always useful for touch-ups.
🧾 Example Calculation
Room wall area: 400 sq ft
Coverage: 350 sq ft/gallon
Coats: 2
Total painted area = 400 × 2 = 800 sq ft
Gallons needed = 800 / 350 = 2.29 gallons
Recommended buy = 3 gallons
💡 Pro Tips for Accurate Paint Estimates
- Always round up — it’s better to have extra.
- Dark colors require more coats.
- Ceilings often require thicker paint.
- If using a sprayer, increase paint estimate by 10–15%.
🏁 Final Thoughts
A paint job looks its best when you plan correctly. Whether you’re doing a full home makeover or a small room refresh, the Paint Coverage Calculator helps you avoid running out of paint or overspending.
