How much paint to buy? Find out before you drive to the store
You are standing in the paint aisle at the hardware store. The room is 13 by 10 feet, four walls, a ceiling, two windows and one door. The question: how many gallons (or liters) of paint should you buy so you do not run out halfway through, and you do not end up with three extra cans sitting in your basement for five years.
Type the room dimensions (length, width, height in meters), the number of windows and doors, how many coats you want, and the paint coverage (the number on the can label: how many square meters one liter covers). The calculator subtracts the window and door area, multiplies by coats, adds a 10 percent buffer for touch-ups and the ceiling if you opt in, and shows a concrete liter amount.
The result is rounded to common tin sizes: 0.5 / 1 / 2.5 / 5 / 10 liters. Multi-room mode lets you add up to ten rooms at once, each with its own dimensions and ceiling toggle. Ideal if you are painting a whole apartment and want to make the paint run only once.
How to use it
- Type the room dimensions: length, width and height in meters. Measure from floor to ceiling, not to the lamp hanging.
- Type how many windows and doors you have, plus the average area of each in square meters. A typical window is 1.6 m², a typical door is 1.8 m². If you have larger ones (a sliding door, a bay window), type a larger number.
- Pick the number of coats: one, two or three. Two coats is the standard, one is enough only if you are repainting the same color on a clean primer. Three coats for dark colors or going from dark to light.
- Toggle the ceiling switch if you want to paint the ceiling too. On by default, because you usually paint both at once.
- Paint coverage is the number from the can label: how many square meters one liter covers. Good acrylic paint has a coverage of 10 to 14 m²/l, cheap paint can be 6 to 8. Check the can, do not guess.
- The calculator shows liters needed with a 10 percent buffer (touch-ups, drips, splatters) and suggested tin combos: for example one 5-liter tin plus one 1-liter tin instead of four small ones.
- Switch on multi-room mode (toggle at the top) to calculate a whole apartment at once. Each room gets its own dimensions and ceiling decision. The total is at the bottom, so you know exactly how much paint to order.
When this is useful
Six typical situations where the calculator saves you store runs and money:
- Painting one room after a renovation. Bedroom after new windows, fresh drywall, you want white walls and ceiling. You type 4 by 3 by 2.7 meters, subtract 2 windows and 1 door, two coats: the calculator shows 6 liters. You buy one 5L tin plus one 1L tin instead of three 2-liter ones.
- Painting a whole apartment before moving in. You switch on multi-room mode, add living room, bedroom, two kids rooms, kitchen and hallway. Each with different dimensions and a different color. The calculator sums paint by type and color, so you know exactly what to order.
- Renting and refreshing the walls. Time and money matter, you do not want extra cans. You type the dimensions, one coat (same color), the result is 3 liters. You buy one 2.5L tin plus one 0.5L and finish in a weekend.
- Planning a renovation budget. You know the square meters to paint, the price per liter, you multiply. A concrete number for the cost spreadsheet, not a guess.
- Helping family with their apartment. Your mom calls "honey, how much paint for my 12-meter room". You type it in, read the answer over the phone, mom drives to the store once, not three times.
- Quoting a job as a painter. The client says "paint my living room and kitchen". You type in the dimensions from your tape measure, add labor, give a price. Concrete numbers on paper, the client sees exactly what they are paying for.