How to Design a Floor Plan With Math

Most rooms are rectangular. Hold your graph paper with the longest side closest to you and the shortest sides to your left and right (sometimes referred to "landscape" layout as opposed to "portrait" orientation). Locate a square three squares up from the bottom of the paper and three squares in from the left of the paper to leave a margin beside and below your drawing. Mark that square with your pencil. Measure the longest wall of your room just above the baseboard. Multiply the number of inches by two. Using the resulting number, count out the same number of squares on your graph paper starting at the square you marked and moving to the right. Mark the last square. Draw a line along the bottom of the row of squares connecting them. (Mathematically, each square that you just drew through represents counting one square on your graph paper for every 6 inches of wall space.)

Measure the two side walls of your room. Individually, multiply the results by two. Count out each of the blocks on your graph paper. For the wall on the right, draw a vertical line radiating up from the last square on the right of the line you drew. For the wall on the left, draw from the furthest to the left square of the line. Connect the lines at the top.

Mark the areas of doors and windows on your graph paper by first measuring the width of each, and then measuring how far from the room corners each begins and ends. Multiply your results by two and count off the squares to mark their locations with a heavy line.

Measure your furnishings. Multiply the lengths and widths by two. Sketch lines indicating the furniture by marking off counted squares, taking care that your doors and windows are not blocked. If the desired result is not received, erase the furniture and place it elsewhere.