Measuring wall area correctly is the foundation of any accurate decorating estimate. When you understand how much surface you are painting, you can budget more realistically, plan paint quantities more confidently, and compare quotes on a like-for-like basis.
The simplest method is to measure each wall separately. Start by measuring the wall width in metres, then measure the wall height from skirting level to ceiling. Multiply width by height to get the wall area in square metres. Repeat this for each wall and then add them together for a total.
Many people ask whether they should subtract doors and windows. You can subtract large openings if you want a closer estimate, but it is often best to only subtract big features, such as a large patio door or a wide window that covers a significant portion of the wall. Smaller windows usually do not change the overall estimate much once you consider that cutting in and edges still take time and still use paint.
If you are measuring multiple rooms, write each room down separately. A combined total is useful, but room-by-room notes make it easier to spot errors, and it helps if your scope changes later.
For ceilings, measurement is even simpler. Measure the room length and width and multiply them to get ceiling area. For example, a room that is 4 metres long and 3 metres wide has a ceiling area of 12 square metres.
If you are working with sloped ceilings or unusual shapes, break the surface into rectangles, measure each rectangle, and add them together. The goal is not perfection down to the last decimal point, but a reliable measurement that is close enough to support sensible budgeting.
If you want help checking measurements or turning them into a realistic decorating estimate, contact P&D Online.