To draw a floor plan to scale, determine the amount of accuracy you need in your drawing. Measure the room's perimeter walls with a tape measure, convert to scale and draw them on graph paper. Measure the size and location of windows, doors and other features, convert and draw them in place. Scale drawings are useful for home remodeling projects, construction, real estate transactions and furniture placement.
If you are creating a drawing so you can paint, remodel or place furniture, measurements can be rounded to the nearest inch. A builder who needs a plan for buying and trimming materials should measure to within 0.25 inches.
Graph paper can help simplify the drawing process. Choose a scale appropriate to both the room and the size paper you are using. If, for example, your room measures 10 by 12 feet, and your graph paper measures 40 by 50 squares, have each square represent 0.25 feet or 3 inches. In this example, draw the 10 foot wall along 40 squares, and the 12 foot wall at a right angle to take up 48 squares. When measuring the room, write down all your figures in terms of inches and use decimals, rather than fractions, to simplify the conversion process.
To place furniture, draw a representation of each piece to scale, and cut it out. Place the pieces of paper on your room drawing, and move them around until you get an arrangement you like.