How Much Paint Do I Need?
Enter your room dimensions to find out exactly how many gallons of paint to buy — walls, ceiling, and trim calculated separately.
How to Calculate Paint for a Room
To calculate paint needed, find the total wall area by multiplying room perimeter by ceiling height. Subtract 21 sq ft per door and 15 sq ft per window. Divide by 350 (sq ft per gallon) and multiply by your number of coats.
For a standard 12×10 room with 8-ft ceilings, 1 door, and 2 windows, you'll typically need about 1.5 gallons for two coats of wall paint.
How Many Coats of Paint Do I Need?
Most paint jobs require 2 coats for an even finish. One coat is only sufficient when repainting with the same or similar color. Going from dark to light always requires at least 2 coats, sometimes 3.
Paint Coverage Quick Reference
| Room Size | Approx Wall Area | Gallons (2 coats) |
|---|---|---|
| 10×10 ft, 8 ft ceiling | ~290 sq ft | 2 gallons |
| 12×12 ft, 8 ft ceiling | ~330 sq ft | 2 gallons |
| 14×16 ft, 8 ft ceiling | ~400 sq ft | 3 gallons |
| 16×20 ft, 8 ft ceiling | ~490 sq ft | 3 gallons |
Coverage rates assume 350 sq ft per gallon per coat, which is a conservative industry standard. Higher-quality paints may cover up to 400 sq ft per gallon. Dark colors applied over light walls may need a third coat — especially deep blues, reds, and blacks.
Paint Finish Guide: Which Sheen for Which Room?
Paint sheen affects both appearance and durability. Flat and matte finishes hide surface imperfections well but don't clean easily; high-gloss finishes are the most durable and washable but show every surface flaw. Choosing the wrong finish for a high-traffic area is a common mistake.
| Finish | Sheen Level | Best For | Washability |
|---|---|---|---|
| Flat / Matte | None | Ceilings, low-traffic walls | Poor — marks easily |
| Eggshell | Low | Living rooms, bedrooms | Moderate |
| Satin | Medium | Kitchens, bathrooms, hallways | Good |
| Semi-gloss | High | Trim, doors, cabinets | Very good |
| Gloss | Very high | Furniture, exterior trim | Excellent |
For most rooms, eggshell or satin on walls with semi-gloss on trim and doors is the standard approach. Bathrooms and kitchens benefit from satin or semi-gloss on walls due to moisture and the need to wipe surfaces clean.