Obtain data for your bar graph. Use yearly sales data of a software company for this example. Use $100,000 in sales for the year 2005, $120,000 in sales for 2006, $180,000 in sales for 2007, $250,000 in sales for 2008, $500,000 in sales for 2009 and $1 million in sales for 2010.
Determine the maximum and minimum values for the data. Conclude that the maximum sales for the data in this example is $1 million, and the minimum is $100,000. Conclude that the maximum year is 2010 and the minimum year is 2005.
Use a vertical scale of 1/2 inch per $100,000 in sales. Calculate that the vertical scale will be a total of five inches high by multiplying 1/2 inch by the maximum sales value -- 1,000,000 -- and dividing the result by 10, which is the number of divisions. Draw 10 horizontal division lines 1/2 inch apart on the vertical axis to indicate sales of $100,000, $200,000, $300,000 and so forth until you reach $1 million.
Draw a horizontal line that starts at the lower point of the vertical line (the vertical axis) and ends on the right edge of your paper. Draw six 1/4 inch vertical division lines every 1 inch on the horizontal axis. Write "2005" directly below the first vertical line so that it is centered about the vertical line. Write down the years 2006, 2007, 2008, 2009 and 2010 sequentially below each division line on the horizontal axis you just drew.
Draw a vertical line that starts on the horizontal axis and is 1/8 inch to the left of the first vertical division line that is labeled with the year 2005. Draw this vertical line so it extends 1/2 inch up, to the level of the $100,000 vertical division mark. Draw a horizontal line from this endpoint that extends 1/4 inch to the right. Draw a vertical line downward from this endpoint to the horizontal axis.
Continue drawing 1/4 inch wide rectangles centered at the year division marks for each year in the same manner as given in step 5. Vary the lengths of each rectangle so the length of the rectangle corresponds to the sales level of the vertical axis.
Calculate that the 2006 rectangle should be 0.6 inches long, the 2007 rectangle should be 0.9 inches long, the 2008 rectangle should be 1.25 inches long, the 2009 rectangle should be 2.5 inches long, and the 2010 rectangle should be 5 inches long. Use the scaling factor of 0.5 inches per $100,000 of sales for these calculations.