Overview
Introduction
Centered headings and banner text in plain-text output need padding split evenly on both sides.
This tool does that for every line of your input.
What Is String Center Aligner?
A centering tool that computes each line's total needed padding and splits it between the left and right sides, using your chosen pad character.
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 String Center Aligner Works
For each line shorter than the target width, the tool computes the total padding needed, floors half of it for the left side, and puts the remainder on the right.
The transformation happens synchronously in JavaScript the moment you type, with no network round trip involved.
When To Use String Center Aligner
Use it for centering a heading or banner in a plain-text file, README, or terminal output.
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 String Left Padder and String Right Padder.
Features
Advantages
- Handles multi-line input, centering every line independently.
- Supports any single pad character, not just spaces.
- Biases the extra character to the right whenever the padding total is odd, a fixed convention that keeps a block of centered lines consistent instead of alternating between left and right.
Limitations
- Assumes a monospace font for the centering to visually line up.
- Doesn't account for full-width or multi-byte characters when measuring line length.
Examples
Best Practices & Notes
Best Practices
- View the result in a monospace font to confirm true visual centering.
- Use a visible pad character like '*' or '-' for a banner effect.
- Set the target width to at least the length of your longest line, since anything longer passes through uncentered and visibly breaks the alignment of the block.
Developer Notes
Padding is split with `Math.floor(totalPad / 2)` on the left and the remainder on the right, so an odd total always biases the extra character to the right side, a common convention for centered text.
String Center Aligner Use Cases
- Centering a heading in a plain-text README or changelog
- Creating a banner effect around a short message
- Formatting a centered title for terminal output
Common Mistakes
- Expecting perfectly even padding when the total needed is an odd number.
- Judging the result in a proportional font, where equal character counts do not produce equal visual widths, so correctly padded text still looks off-center.
Tips
- Use a decorative pad character like '*' or '=' for banner-style centered text.
- Match the width to your terminal or code-comment convention (72 or 80 is typical) so centered banners line up with the surrounding content.