Paste your text and fix loose hyphens into proper em dashes and en dashes, with a diff preview and a toggle for each rule.
Em dashes signal a break or interruption; en dashes signal a range. Mixing them up reads as sloppy.
The diff preview shows exactly what was struck out and what replaced it, so nothing is a surprise.
Turn any individual rule off if you only want to fix one kind of dash at a time.
Typewriters and most keyboards only have one hyphen key, so writers have long typed a plain hyphen to stand in for two different, longer dash characters. An em dash, roughly the width of a capital M, is the mark used for a parenthetical aside or a sudden break in a sentence — like this one — and is written with no spaces around it in standard American style. This tool treats a hyphen with a single space on each side, " - ", as that pattern and swaps it for a real em dash while removing the surrounding spaces. An en dash, roughly the width of a capital N, is the correct mark for a range between two numbers or dates, such as pages 10–15 or the years 1990–1999, and unlike the em dash it keeps no spaces on either side. This tool detects a hyphen sitting directly between two digit runs and swaps it for a real en dash. Finally, many people type two or three hyphens in a row, "--" or "---", as an improvised em dash, particularly in plain-text email or Markdown; this tool recognizes that pattern too and converts it to a single proper em dash. Every rule can be switched off independently, and the diff preview always shows the exact old text struck through next to the new text underlined, so you can verify each change before copying.
Used for asides and breaks in a sentence, with no surrounding spaces.
Used between numbers and dates, also with no surrounding spaces.
Each of the three detection rules can be turned on or off on its own.
It looks for three common hyphen typing patterns: a hyphen surrounded by single spaces, a hyphen sitting directly between two numbers or years, and two or three hyphens in a row, and replaces each with the correct dash character.
An en dash is the typographic convention for a range between two numbers or dates, like pages 10-15 or the years 1990-1999. An em dash is used for a parenthetical break or interruption in a sentence, which is what a hyphen surrounded by spaces usually represents.
Yes. Each of the three rules has its own toggle, so you can disable, for example, the number-range rule while keeping the space-hyphen-space and double-hyphen rules active.
No. The number-range rule only matches when digits sit directly on both sides of the hyphen, and the other rules require spaces or a doubled hyphen, so ordinary hyphenated words are left untouched.
Yes. All matching and replacement happens locally in your browser with plain JavaScript, and your text is never uploaded anywhere.
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