How to plan paint for several rooms
Last reviewed: November 2, 2026
Group your surfaces by paint, not by room. Add up the area for each paint, work out one quantity for each, and choose containers from that total.
Benjamin Moore gives the same advice for rooms in one color: add up the total square footage.
Why the total beats room-by-room buying
Two rooms use the same paint. One needs 1.60 US gallons, and the other needs 0.80. You can buy quarts and gallons, and you want the least paint.
| Approach | Containers | Total |
|---|---|---|
| Least paint per room | Room 1: 1 gal + 3 qt. Room 2: 1 gal | 2.75 gal, 5 containers |
| Least paint on the total of 2.40 gal | 2 gal + 2 qt | 2.50 gal, 4 containers |
Rounding up room by room adds extra paint each time. Rounding once, on the total, avoids that.
Keep different paints apart
Combine figures only where the paint is the same:
| Paint | Rooms and surfaces | Area | Coats | Coverage |
|---|---|---|---|---|
| Paint A | Bedroom walls, hall walls | |||
| Paint B | Bathroom walls | |||
| Ceiling paint | All ceilings |
Copy this table, and fill in one row for each paint. A row is a single calculation. The same product in two colors is two rows, because you can’t share a can. If coats differ between rooms, keep them on separate rows.
How to do this in the calculator
The calculator handles one calculation at a time, and doesn’t yet save rooms. To combine rooms that share a paint:
- Choose Wall by wall.
- Add a wall row for every wall in every room.
- Enter what to deduct for each wall.
- Enter your coats, coverage, and container sizes once.
The result is a single quantity and container plan for all of them.
Check before you buy
Add up your rows once more, and make sure no room has been left out. Then copy the quantities onto the printable checklist so everything is on one list.