<P> Traditional line length research , limited to print based text , resulted in a variety of results but generally for printed text it is widely accepted that line length fall between 45 - 75 characters per line ( cpl ) , though the ideal is 66 cpl ( including letters and spaces ) . For conventional books line lengths tend to be 30 times the size of the type , but between 20 and 40 times is considered acceptable ( i.e. 30 x 10pt font = 300 pt line ) . Early studies considered line lengths between 59 -- 97 mm ( about 57 cpl ) is optimum for 10 point font . For printed works with multiple columns 40 - 50 cpl is often better . For justified , English language text the minimum number of characters per line is 40 characters ; anything less than 38 - 40 characters often results in splotches of white spaces ( or rivers ) or too many hyphenations in the block of text . Longer lines ( between 85 - 90 cpl ) may be acceptable for discontinuous text such as in bibliographies or footnotes , but for continuous text lines with more than 80 characters may be too long . Short text , such as ragged marginal notes , may be as little as 12 - 15 characters per line . Studies have shown that short lines are often preferred over long lines by study participants , likely because they feel more at ease with format , which contradicts research suggesting longer lines are best for quick reading . </P>
<P> Traditional line length research , limited to print based text , resulted in a variety of results but generally for printed text it is widely accepted that line length fall between 45 - 75 characters per line ( cpl ) , though the ideal is 66 cpl ( including letters and spaces ) . For conventional books line lengths tend to be 30 times the size of the type , but between 20 and 40 times is considered acceptable ( i.e. 30 x 10pt font = 300 pt line ) . Early studies considered line lengths between 59 -- 97 mm ( about 57 cpl ) is optimum for 10 point font . For printed works with multiple columns 40 - 50 cpl is often better . For justified , English language text the minimum number of characters per line is 40 characters ; anything less than 38 - 40 characters often results in splotches of white spaces ( or rivers ) or too many hyphenations in the block of text . Longer lines ( between 85 - 90 cpl ) may be acceptable for discontinuous text such as in bibliographies or footnotes , but for continuous text lines with more than 80 characters may be too long . Short text , such as ragged marginal notes , may be as little as 12 - 15 characters per line . Studies have shown that short lines are often preferred over long lines by study participants , likely because they feel more at ease with format , which contradicts research suggesting longer lines are best for quick reading . </P>
what is the optimal line length for ideal legibility
what is the optimal line length for ideal legibility
66 cpl ( including letters and spaces )
66 cpl ( including letters and spaces )