Article in English: To figure out how much a paint job will cost, or how much you plan to charge, you need to know the square footage of the wall and/or ceiling you're painting. You can find this somewhere in the paperwork you signed when buying or renting your home. If you're painting for someone else, ask them for the information. However, if you don't have that information on hand, use a ruler or tape measure to measure the length and width of the home/room. You can enter this into an online calculator to determine the square footage. Not every inch of a home or room will be painted, so subtract as necessary. Doors, windowsills, and trim will all need to be painted, but windows will not be painted, so measure these areas and subtract their measurements from the total square footage. As a general estimate, you can subtract about 20 square feet per door and 15 square feet per window. Say a 700 square foot room has one door and two windows. You would subtract 20 for the door, and 30 for the window, resulting in a square footage of 650. A gallon of paint covers 250 square feet. So, a room that's 650 square feet would need roughly two gallons of paint because 650 divided by 250 comes out to about 2.6. However, you always need two coats, so expect to buy around six gallons of paint for a room of this size. Once you've determined how much paint you need, figure out how much your paint will cost. Paint costs vary depending on factors like color and quality. Paint is generally $20 to $40 per gallon, with higher quality paint costing more. Say you want two coats of a decent quality paint for a 650 square foot room, which requires six gallons of paint. If you plan to buy paint at $30 a gallon, expect to pay around $180 for paint. What supplies do you have and what supplies do you need to buy? You will likely need masking plastic, masking paper, paint tape, caulking, tarps, brushes or rollers, and a gallon of primer.  Find the average cost of these supplies by visiting local suppliers and adding up the total. For example, say the masking...

Summary in Indonesian:
Ukur area pengerjaannya. Kurangkan area yang tidak dicat. Hitunglah jumlah cat yang dibutuhkan. Hitunglah biaya catnya. Hitunglah biaya materialnya.