Hyphen and Dash Checker

How to Use the Hyphen and Dash Checker

1. Paste your text and pick a style. APA 7 and Chicago 18 agree on almost everything here; Chicago also sets two-person names such as Mann–Whitney with an en dash.
2. Read the colours. Rose marks a mechanical fix with a replacement shown. Amber marks something that depends on your sentence, such as an en dash between two ordinary words.
3. Open each group. Every kind of issue says why the change is made, names the source, and lists each case with the replacement.
4. Apply fixes. Click Apply for one, or Apply all for every ready-to-fix item. Quoted passages, URLs, DOIs and ISSN/ISBN numbers are left alone.

Hyphen, En Dash, Em Dash: The Short Version

A good rule of thumb: the longer the mark, the bigger the gap it spans. A hyphen holds two words together, an en dash stretches across a range, and an em dash opens a gap in the sentence itself.

What the Style Guides Say

• Ranges take an en dash. APA 7 writes page ranges as pp. 45–67. The Chicago Manual of Style (18th ed., ¶ 6.83) sets consecutive numbers that express a range with an en dash. Once from or between introduces the range, write from 1990 to 2000 or between 5 and 10 instead of from 1990–2000 or between 5–10.
• A compound modifier is hyphenated before its noun, not after. A well-known author, but the author is well known. Chicago has taught this since its first edition and, in the 18th edition, keeps its sparse approach (¶¶ 7.92, 7.96): an up-to-date solution but the equipment was up to date. APA's hyphenation guidance (7th ed., §§ 6.11–6.12) gives the same pattern for low-income families and evidence-based practice, and follows Merriam-Webster for individual compounds.
• An -ly adverb is not hyphenated. Chicago leaves highly educated and newly hired open (¶ 7.96, section 2).
• Two people’s names used as a modifier take an en dash in Chicago 18. Epstein–Barr virus, Kaplan–Meier curve. This is new in the 18th edition and does not reach place or company names such as Winston-Salem or Merriam-Webster (¶ 6.85).
• Em dashes are closed up. Neither APA nor Chicago puts spaces around an em dash. A spaced en dash for an aside is British practice, so the checker lets you allow it with one tick.
• An en dash can join an open compound. Chicago permits pre–Civil War or New York–London flight, where a hyphen would join only part of the modifier (¶ 6.86), but advises rewording where possible. The checker flags an en dash between two plain lowercase words as a likely mistyped hyphen.

What the Checker Looks For — and What It Cannot

The widget's example paragraph has 11 issues in 8 kinds, and 12 in 9 under Chicago, where Mann-Whitney becomes Mann–Whitney. Applying every fix turns aged 18-25 … from 2010-2015 -- a well known low income sample into aged 18–25 … from 2010 to 2015—a well-known low-income sample, and the sample was very well-known into very well known.

It is a pattern checker, not a grammar parser. The compound rules work from a list of about seventy common compounds and over a hundred -ly adverbs, so it is precise about those and silent about others. It ignores compounds followed by a comma, such as the first element of a well known, low income sample, because it cannot tell a modifier from a noun phrase there. It does not check prefixes (postsecondary, meta-analysis) and it will not know a technical term your field hyphenates. When Merriam-Webster or your own style guide disagrees, follow them.

Frequently Asked Questions

What is the difference between a hyphen, an en dash and an em dash?

A hyphen (-) joins the parts of a compound word, such as well-known. An en dash (–), about the width of an n, marks a range such as 45–67 and, in some cases, links equal-weight or paired words. An em dash (—), about the width of an m, sets off a break or an aside in a sentence.

Should page ranges use a hyphen or an en dash in APA?

An en dash: pp. 45–67. A hyphen is a common substitute in drafts, which is why the checker fixes it. APA's reference examples use the en dash in page ranges, and so does Chicago for all ranges of numbers.

Do I hyphenate a compound modifier like “well known”?

Before the noun, yes: a well-known author. After the noun, normally no: the author is well known. Both APA and Chicago follow this, and Chicago adds that a few compounds such as all-consuming keep their hyphen in any position. If a compound is not on the checker's list, look it up in Merriam-Webster.

Is it “highly-educated” or “highly educated”?

Highly educated. Chicago leaves a modifier made of an -ly adverb and an adjective or participle open, because the adverb cannot be mistaken for part of a noun phrase. The checker removes the hyphen from a list of common -ly adverbs.

Do I put spaces around an em dash or an en dash?

In APA and Chicago, no spaces around an em dash or around an en dash in a range. British publishers often use a spaced en dash ( – ) for the same job as an em dash. The checker reports spaced en dashes by default and has an option to allow them.

Why does the checker leave 2020-10-05 and COVID-19 alone?

Those hyphens are part of a date, an identifier or a name, not a range. The range rule skips ISO dates, phone numbers, years followed by a month, anything with a letter attached to the number, and sums such as 10-5=5.

Is my text uploaded or checked by AI?

Neither. The checker applies fixed patterns in your browser, so the same text always gets the same result and nothing is sent anywhere.