What is a Block Letter? A block letter is a style of formal letter writing where all text is aligned to the left margin. This style is favored for its straightforward presentation, which eliminates the need for indentations and keeps the layout clean and simple. Enter your text and choose your block letter font, color and size to generate your own block letter image. You can print, download or share your block letter graphic with ease. Block letters may also be used as a synonym of block capitals, which means writing in all capital letters, imitating the style of typeset capital letters. These examples are from corpora and from sources on the web. Learn what block letter means in typing, writing, and business letter formats. See how to convert text into block letters and compare them with cursive letters.