English uses three distinct horizontal marks that look similar but serve very different purposes: the hyphen (-), the en dash (–), and the em dash (—). The hyphen is the shortest and most common — it joins word parts and creates compound adjectives. The en dash (roughly the width of the letter N) indicates ranges of numbers, dates, and distances. The em dash (the width of the letter M) creates a stronger pause in a sentence than a comma, similar to parentheses but with more emphasis. Understanding the difference between these three marks, as clarified by Oxford Learner's Dictionaries, is important for polished academic writing, professional communication, and English examinations at B2 and above. Many writers use a hyphen for everything, which is understandable but technically imprecise. This guide will give you clear rules for each mark so you can use them with confidence.
Formation / Rules
| Mark | Name | Main Uses | Example |
|---|---|---|---|
| - | Hyphen | Compound adjectives before noun; prefixes; compound numbers | well-known author; pre-2020; twenty-one |
| – | En dash | Ranges (numbers, dates, pages); compound adjective with multi-word element | pages 10–45; 2020–2025; New York–based |
| — | Em dash | Strong parenthetical break; interruption; appositive | She arrived—finally—at noon. |
Examples
- She is a well-known author. (compound adjective before noun — hyphen)
- The author is well known. (predicative — no hyphen needed)
- Read pages 12–56 for tomorrow. (range — en dash)
- The 2020–2024 strategy was successful. (date range — en dash)
- The answer—surprisingly—was correct. (parenthetical — em dash)
- He has a five-year plan. (compound adjective — hyphen)
- She is a Nobel Prize–winning scientist. (multi-word compound — en dash)
- My brother—the one who lives in Paris—is visiting. (appositive — em dash)
- The score was 3–1 at half time. (score range — en dash)
- She was re-elected for a third term. (prefix to avoid double vowel — hyphen)
Common Mistakes
| Wrong | Correct | Explanation |
|---|---|---|
| a well known writer | a well-known writer | Compound adjective before noun needs a hyphen. |
| pages 10-45 (hyphen) | pages 10–45 (en dash) | Ranges use an en dash, not a hyphen. |
| She arrived - finally - at noon. | She arrived—finally—at noon. | Parenthetical breaks use em dashes, not hyphens with spaces. |
| a high-quality product (after noun) | a product of high quality | Hyphenated compounds are not needed in predicative position. |
| twenty one students | twenty-one students | Compound numbers 21–99 are hyphenated. |
Practise
Grammar Quiz
Choose the correct mark: hyphen, en dash or em dash.
Cloze Dropdown
Select the correctly hyphenated compound adjective form.
Complete the Sentence
Add the correct dash or hyphen to complete each sentence.
Practice What You’ve Learned
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Frequently Asked Questions
What is the difference between a hyphen and a dash?
A hyphen (-) joins words or word parts (compound adjectives, prefixes). An en dash (–) shows ranges (pages 10–20, 2019–2023). An em dash (—) marks a strong break in a sentence, like a parenthetical aside. They are different lengths and have different uses.
When should I use a hyphen?
Use a hyphen to form compound adjectives before a noun (well-known author, five-year-old child), to join prefixes to proper nouns or numbers (pre-2020, anti-inflammatory), and in fractions and compound numbers (twenty-one, three-quarters).
Do compound adjectives always need a hyphen?
Hyphenate compound adjectives when they appear before the noun they modify: a well-known author, a long-term plan. After the noun (predicative position), no hyphen is needed: The author is well known. The plan is long term.
What is an en dash used for?
The en dash (–) is used for ranges of numbers, dates, or pages: pp. 45–78; June–August; the 2020–2024 period. It is also used in compound adjectives where one element is itself a compound: New York–based company.
What is an em dash used for?
The em dash (—) creates a strong pause or parenthetical insertion: She finally arrived—three hours late—without an apology. In British English, an en dash with spaces is often used instead. Both indicate a break stronger than a comma.
Should I use a hyphen with prefixes?
Many prefixes do not need a hyphen: prehistoric, unhappy, rewrite. Use a hyphen when the prefix is followed by a proper noun (un-British), when it ends and the root begins with the same vowel (co-operate), or when ambiguity arises (re-cover vs recover).
Is it ‘e-mail’ or ‘email’?
‘Email’ (no hyphen) is now the dominant modern spelling in most style guides and is preferred by AP, Oxford, and Cambridge dictionaries. ‘E-mail’ (with hyphen) was the original spelling and is still found in formal and legal contexts. Consistency matters more than the choice itself.
How do I type an en dash or em dash on a keyboard?
On Windows: en dash = Alt+0150 (numpad); em dash = Alt+0151 (numpad). On Mac: en dash = Option+hyphen; em dash = Option+Shift+hyphen. In Word, typing two hyphens between words usually auto-corrects to an em dash.
Can I use a hyphen instead of an en dash for number ranges?
In informal writing and most everyday contexts, a hyphen is commonly used for ranges (pages 10-20) and is universally understood. In formal publishing and academic writing, the en dash is technically correct for ranges. Most style guides accept the hyphen in digital text.
Are hyphen and dash errors common in IELTS writing?
Hyphen errors (missing or unnecessary hyphens in compound adjectives) are noted in IELTS and Cambridge writing assessments. Focus on compound adjective hyphenation as the most testable hyphen rule: hyphenate before the noun, not after.