Overview
Introduction
Fully justified text, where both the left and right edges of a paragraph line up evenly, is a common look in print and formal documents.
Achieving it in plain text by hand means carefully counting characters and inserting the right number of extra spaces between words on every line.
What Is Text Justifier?
A justifier that distributes extra spaces evenly between the words of each line so the line reaches an exact target width, leaving the last line of each paragraph untouched.
It runs entirely client-side as part of this site's String Tools collection, so nothing you paste is ever uploaded to a server.
How Text Justifier Works
For each line except the last in a paragraph, the tool splits it into words, computes how many extra spaces are needed to reach the target width, and spreads that count as evenly as possible across the gaps between words, giving any remainder to the leftmost gaps.
Paragraphs are detected by blank lines in the input, and the transformation happens synchronously in JavaScript the moment you type.
When To Use Text Justifier
Use it to prepare plain-text output that mimics a justified print layout, format monospace documentation, or create an evenly edged text block for a terminal UI.
It's a fast way to get the answer without opening a code editor, a REPL, or writing a one-off script just to check.
Often used alongside Word Wrapper, String Left Aligner and String Right Padder.
Features
Advantages
- Distributes extra spacing evenly rather than dumping it all in one gap.
- Correctly leaves the final line of each paragraph unjustified, matching conventional typography.
- Detects paragraph boundaries from blank lines, so the closing line of every paragraph is left unjustified rather than only the very last line of the input.
Limitations
- Lines must already be broken at the desired width; this tool doesn't re-wrap text, only stretches existing lines (pair it with the Word Wrapper tool first).
- Assigns the remainder spaces to the leftmost gaps, so justified lines run slightly wider on the left, which is noticeable on short lines with few words.
Examples
Best Practices & Notes
Best Practices
- Run text through a word wrapper first so each line is already close to the target width before justifying, which keeps the extra spacing subtle.
- Run the Word Wrapper first at the same width you intend to justify to, since this tool stretches existing lines rather than re-breaking them.
- View the result in a monospace font, because evenly distributed spacing only looks even when every character has the same width.
Developer Notes
Paragraphs are split on blank-line boundaries (`/\n\s*\n/`); within each paragraph, every line except the last is justified by computing `baseSpaces = Math.floor(totalSpaces / gaps)` and distributing the `remainder` to the leftmost gaps so spacing differs by at most one space per gap.
Text Justifier Use Cases
- Formatting a plain-text document to mimic a print-style justified paragraph
- Creating an evenly edged text block for a terminal-based UI
- Preparing monospace documentation with clean right-hand margins
Common Mistakes
- Applying justification to lines that are much shorter than the target width, which stretches spacing so much the text becomes hard to read.
- Justifying text that was wrapped to a different width, which leaves lines either barely stretched or padded out with distractingly large gaps.
Tips
- Choose a target width close to your longest natural line length to avoid excessive stretching on shorter lines.
- A line holding a single word has no gaps to distribute into, so it passes through at its original width no matter what target you set.