Left-aligned, flush-left, ragged-right—these are all names for the most standard text alignment most students and most readers see. This text is left-aligned and ragged-right because each line starts at the same place on the left, while the right side of the text has different depths, making it appear ragged, with spaces between words and letters standard and consistent. Standard essays are almost always left-aligned, with sometimes drastically different line lengths.

Books published in English, on the other hand, are most commonly left-justified. Which means that the space between words and letters changes each line in order to try to make both the left and right edges the same length—to have no “rag.” If you’re writing in Google Docs, this is interpreted as generally justified, without the specificity that some typesetting programs have. This paragraph is justified, but not hyphenated, because the words at the end of each line are not split into two lines. Meanwhile some justification defaults include hyphenation to ideally have more consistent spacing but still have non-ragged edges. 

Center-alignment is commonly used for titles or very short lines of information, because having too many lines centered means that where the reader starts, each line might be a bit different. 

By luck or strategy, sometimes the lines are similar lengths.

If you have a long block of text centered, the eye has to bounce back and forth, so no expectations of consistent starting and stopping of lines, possibly making it harder to keep your place.

What about right-alignment?

In English, text is rarely right-aligned (AKA flush-right and ragged-left), at least partially because English is read from left to right, letter by letter. If you read Arabic, you will read right-to-left, and therefore your “default” starting point for a line will be the right and your text will more often be right-aligned. 

So, in English, when would you want to use right-aligned text? 

Right alignment breaks away from the standard, so it can stand out. You might want to use it for a title on a poster, where long-term readability is not as important as boldness. In a book, if you have multiple subheadings—a chapter title, a date or time, and the text of the chapter itself—rather than centering both the chapter title and the date/time as a subtitle, you could right-align the date. Having alignment in your repertoire of hierarchy can reduce other methods of typographical hierarchy, so you can use fewer fonts or combine bolds and italics with alignment to draw more contrast or break a rhythm.

One of the most common instances where you should use right alignment is when a caption or subtitle to a figure is needed. When a figure is on the right side of the page—especially when it is the left page in a spread and you do not want the gutter (inside crack of the book) to swallow it up—right-aligning the text of the caption to the left edge of the figure will connect the figure with the caption and separate it from other text.

For example, I can right-align this text to the picture on the right so that attention is drawn to connecting the image with my caption.  Fig.1 (on right): A picture of a children’s book shows a tiger hiding in the grass, with its own caption describing it, along with other similar short descriptions for what we can assume are similar pictures on the edge of the image. Photo by Waldemar on Unsplash.

This alignment is used for larger chunks of text, unlike using right-alignment for contrast, but you will rarely see this outside of books with photos or other figures, like textbooks or artbooks. 

Right-Aligned Text as Subtitles or Sectioning Notes

In some cases, right-alignment can be used in a similar way—as a sort of “outside”-alignment for subtitles or breaks in the margins, especially in combination with other ways of emphasizing a hierarchy.

Right-alignment is not uncommon in textbooks or shorter-form non-fiction, but if you are writing and formatting fiction, you’ll probably want to stick to left-aligned and left-justified text. Sometimes the stark contrast of right-aligned text can offer a bit of spice or a break in long sections of text.