Optimized line heights and line lengths prevent eye strain and make long-form content easier to digest.
If users can't read your content comfortably, they won't stay. Good readability is a cornerstone of usability; it reduces cognitive load, prevents eye strain, and makes scanning for information effortless. It ensures that the message is delivered effectively without the user having to struggle with the interface, which in turn builds trust and credibility.
Adjust the parameters to see how they affect the reading experience. Notice how line length and line height need to balance each other.
Typography is the art and technique of arranging type to make written language legible, readable, and appealing when displayed. The arrangement of type involves selecting typefaces, point sizes, line lengths, line-spacing (leading), and letter-spacing (tracking), and adjusting the space between pairs of letters (kerning pairs). The term typography is also applied to the style, arrangement, and appearance of the letters, numbers, and symbols created by the process.
Good readability is crucial for user experience. If the lines are too long, the eye has trouble tracking back to the start of the next line. If they are too short, the eye has to travel back too often, breaking the rhythm. Line height that is too tight makes the text look cluttered, while too loose makes the lines feel disconnected.
The vertical space between lines of text (leading). For body text, a line height of 1.4 to 1.6 times the font size is ideal. This gives text enough room to breathe, preventing lines from visually merging and making it easier for the eye to track from the end of one line to the start of the next.
The number of characters in a single line of text (measure). For optimal reading on screens, aim for a range of 45-75 characters. Lines that are too long are hard to track, while lines that are too short create a choppy, disjointed reading rhythm.
The space between characters (tracking). For body text, the default is usually sufficient. For headings, a slight negative tracking (e.g., -0.01em) can create a tighter, more impactful look. For all-caps or small text, a slight positive tracking can improve legibility.
The space between paragraphs. This is more effective than indenting the first line for screen-based reading. Use a clear vertical space (e.g., equal to one line of text) to signal a new thought and give the reader a brief pause, breaking up intimidating walls of text.
Ensure text color contrasts sufficiently with the background (WCAG AA).
Check line lengths on different screen sizes to ensure they don't get too wide.
Add sufficient whitespace around text blocks to prevent a cluttered feel.