Planning result
A 14x16 room with 8 foot walls, one door, three windows, two coats, and 10% waste needs about 2.3 gallons at 400 sq ft per gallon. Buying 3 gallons is the practical planning result for most wall-paint jobs.
Assumptions
| Room size | 14 ft by 16 ft with 8 ft walls. |
|---|---|
| Openings | One 21 sq ft door and three 12 sq ft windows. |
| Coats and waste | Two finish coats plus 10% waste. |
| Coverage | 400 sq ft per gallon per coat for planning. |
Calculation
| Step | Result | Formula |
|---|---|---|
| Wall area | 480 sq ft | 2 x (14 + 16) x 8 |
| Openings | 57 sq ft | 21 + 12 + 12 + 12 |
| Paintable wall area | 423 sq ft | 480 - 57 |
| Two-coat area | 846 sq ft | 423 x 2 |
| Waste-adjusted area | 931 sq ft | 846 x 1.10 |
| Estimated paint | 2.33 gallons | 931 / 400 |
Plan by product coverage
If the selected paint lists 350 sq ft per gallon, the same room moves closer to 2.7 gallons. That still rounds to 3 gallons for wall paint.
Separate trim and doors
Trim, baseboards, window casing, and door slabs often use a different sheen and should be estimated outside the wall paint amount.
Next step
Use the linked calculator or planning hub to adjust dimensions, waste, coverage, depth, spacing, or product packaging for the real project.
Related guides
FAQ
How many gallons for a 14x16 room?
This example lands around 2.3 gallons at 400 sq ft per gallon, so 3 gallons is a practical buy.
What if the room has 9 foot walls?
Increase the wall area to 540 sq ft before openings, then repeat the same steps.
Does primer reduce paint amount?
Primer can improve coverage, but it is a separate product and should be estimated separately.