Steps

Measure the length of the longest wall. If you’re making a floor plan of an actual physical space (as opposed to something you’re designing or imagining), measure it with a tape measure.

Scale this measurement down so that it will fit onto a sheet of graph paper. First, count the number of squares on the longest side of the graph paper (ex. 39 squares); this is the side that will accommodate the longest part of the plan. Then, scale down the length of the wall by reducing it down to a smaller number. Dividing it evenly is preferable, as it’s much easier to remember that one square equals 1 meter as opposed to, say, 1.27 meters, but if the length of the wall isn’t cleanly divisible, you may have to have an imperfect scale.
If you need additional guidance, see examples in both feet and meters below.
 If the wall measures an even number of units (ex. 90 feet), try dividing it by 2, 3, 4, etc. and seeing if the resulting number is smaller than the number of squares. (90 feet divided by 2 is 45 – too large to fit across 39 squares. 90 feet divided by 3, on the other hand, is 30, which will fit nicely across 39 squares with room to spare.)
 If the wall measures an odd number of units (ex. 81) try dividing by 3, 5, etc. and seeing if the resulting number is smaller than the number of squares. (81 feet divided by 3 is 27, which will fit across 39 squares with room to spare.)
 If the wall measures a number of units that is smaller than the number of squares (ex. 27 meters), you can scale it to 1 unit per square. (1 meter = 1 square, making that wall 27 squares long).
 If the number of units is very small and would result in a tiny drawing(ex. 15 meters across 15 squares, leaving most of the page blank), try doubling or otherwise increasing the number of squares used to depict each unit. (1 meter over 2 squares would make that wall 30 squares long).
 If you aren’t happy with the size your simplified scale produces or the number simply won’t divide evenly (ex. 89 feet), try dividing the larger number by the smaller one. However, unless you want the wall to take up the entire length of the graph paper, don’t include the full number of squares in your calculation; leave at least one square on either side so that your floor plan doesn’t get messy (i.e. subtract 2 squares). (89 feet divided by 37 squares is 2.4 feet – or nearly 2’5” – per square, making that length of wall 37 squares long and leaving one empty square on either side of the drawing.)

Measure the length of the other walls and convert these measurements to your scale. If, for example, you determined that each square equals 3 feet, a wall measuring 40 feet would be 13 1/_{3} squares long (because 40 divided by 3 = 13 1/_{3}); if you determined that each square equals 1 meter, a wall measuring 18 meters would be 18 squares long.

Measure the length of each door and window opening (without frames) and convert these measurements to your scale.

5
Incorporate all walls, windows, and doors on your floor plan. Draw each window as double lines and each doors as a line (i.e. the fullyopened door) with an arc (i.e. the actual swing path of the door; useful when trying to place furniture).