Missing hyphen: number + page/step/star

Small punctuation changes-a missing hyphen or the wrong dash-can alter meaning or slow a reader. Below are the most common hyphenation slips (number-word adjectives, ranges, star/step phrases, and compound modifiers) with quick fixes and copy-ready rewrites.

If you're checking correctness or fixing a sentence, use the rewrite templates and the before/after pairs to make fast edits.

Quick answer: When to hyphenate

Hyphenate compound modifiers that appear before a noun (a well-known artist), number-word adjectives (a 21-year-old intern), and fixed multiword modifiers (step-by-step). Use an en dash (no spaces) for ranges (pages 10-12). If the phrase follows the noun, you usually don't hyphenate (the artist is well known).

Before a noun as a single descriptor → hyphenate: "a five-star hotel".
Number + unit as adjective (age, measurement, length) → hyphenate: "a 3-week trial".
Ranges → use an en dash with no spaces: "pages 10-12".
If an adverb ends in -ly, do not hyphenate: "a highly respected scientist".

Core hyphenation rules

Hyphens connect words that act as a single idea before a noun or link numbers to words used adjectivally. They prevent misreading and show which words belong together.

Hyphenate before the noun: a state-of-the-art device; no hyphen when after the noun: the device is state of the art.
Hyphenate number-word adjectives: a 10-page report; a twenty-one-year-old student.
Don't hyphenate adverb + adjective when the adverb ends in -ly: a clearly written report (no hyphen).

Wrong: We stayed at a five star hotel.
Right: We stayed at a five-star hotel.
Wrong: She is a 21 year old graduate.
Right: She is a 21-year-old graduate.

Numbers, ages, stars, and steps

When a number + word modifies a noun, hyphenate: 3-page report, 7-foot ladder, five-star review. Ages written as adjectives get hyphens before a noun: a 5-year-old subject. For ranges (page numbers, years, ratings), prefer an en dash with no spaces; if unavailable, use a hyphen without spaces.

Adjectival ages and measurements: hyphenate (a 2-month trial).
Star ratings and step phrases: hyphenated when they modify a noun (a five-star hotel; a step-by-step guide).
Ranges: en dash, no spaces: "10-12" (fallback: "10-12" with no spaces).

Wrong: Submit a 3 page proposal by Monday.
Right: Submit a 3-page proposal by Monday.
Wrong: Everyone completed the step by step worksheet.
Right: Everyone completed the step-by-step worksheet.
Wrong: Pages 5 - 10 include the appendix.
Right: Pages 5-10 include the appendix.
Work - Usage: Please finish the two-week sprint tasks before the demo.
School - Usage: Turn in a one-page summary with your thesis.
Casual - Usage: I booked a five-star place for the weekend.

Hyphen vs en dash vs spacing

A hyphen (-) joins words; an en dash (-) shows ranges. Avoid spaces around the mark for ranges: write "5-10" (or "5-10" if you can't type an en dash), not "5 - 10". Compound modifiers should have no spaces around hyphens.

Ranges: en dash, no spaces: "pages 10-12" or "1999-2003".
Compound modifiers: hyphen, no spaces: "high-quality data".
Fallback: if your platform lacks an en dash, use a hyphen with no spaces: "10-12".

Wrong: Pages 10 - 12 list all references.
Right: Pages 10-12 list all references.
Wrong: A well - known artist arrived late.
Right: A well-known artist arrived late.
Casual - Usage: I'm on a 24-hour shift today (hyphen links 24 and hour).

Compound modifiers and adjective chains (grammar notes)

When multiple words work as a single descriptor before a noun, hyphenate them. Don't hyphenate when the modifier follows the noun or when an -ly adverb is present. Long chains can often be rephrased to reduce clutter.

Hyphenate before the noun: "long-term plan", "state-of-the-art equipment".
Do not hyphenate after the noun: "The plan is long term."
Do not hyphenate adverb + adjective with -ly: "a highly regarded colleague".

Wrong: They invested in state of the art equipment.
Right: They invested in state-of-the-art equipment.
Wrong: We followed a long term strategy to reduce churn.
Right: We followed a long-term strategy to reduce churn.
Work - Usage: We rolled out a company-wide policy last quarter.

Fix your sentence: quick rewrite templates

If two words before a noun act as one idea, hyphenate them. If hyphenation makes the sentence awkward, rephrase to split or clarify the idea.

Template: "a" + [modifier-as-unit] + "-" + [noun] → "a well-known author", "a 10-page report".
When hyphens pile up, reword: "the design that is state of the art" → "the state-of-the-art design" or "the design, which is state of the art, ...".
Swap test: move the modifier after the noun. If it still reads naturally, you probably don't need a hyphen.

Rewrite:
Original: "We booked a five star hotel for the conference."
Rewrite: "We booked a five-star hotel for the conference."
Rewrite:
Original: "She's a 21 year old intern this summer."
Rewrite: "She's a 21-year-old intern this summer."
Rewrite:
Original: "Follow the step by step protocol."
Rewrite: "Follow the step-by-step protocol."
Rewrite: Alternative (if hyphens clutter): "We will implement a strategy for the long term." (instead of "a long-term strategy")

Try your own sentence

Test the whole sentence rather than just the phrase: context often makes the right choice obvious. Use the swap test, the number rule, or paste the sentence into a checker for suggestions.

Examples and common scenarios (work, school, casual)

Grouped examples show the minimal edit you need. Keep the hyphen when the phrase modifies a noun; drop it or reword when it follows the noun.

Wrong: Please review the third party security report before the meeting.
Right: Please review the third-party security report before the meeting.
Wrong: We need a user friendly interface to meet the deadline.
Right: We need a user-friendly interface to meet the deadline.
Wrong: Submit the ten page appendix with your report.
Right: Submit the ten-page appendix with your report.
Work - Usage: Prepare a client-facing slide deck for the two-week sprint review.
Work - Usage: The third-party vendor completed the audit ahead of schedule.
Work - Usage: We scheduled a company-wide meeting for Friday.
Wrong: The student wrote a high school reunion essay for class.
Right: The student wrote a high-school reunion essay for class.
Wrong: Everyone completed the step by step worksheet in class.
Right: Everyone completed the step-by-step worksheet in class.
School - Usage: Submit a one-page abstract before the deadline.
School - Usage: Use a step-by-step approach when writing lab procedures.
School - Usage: The five-year study showed consistent improvements.
Wrong: I'm meeting my high school friend tonight.
Right: I'm meeting my high-school friend tonight.
Wrong: She made a two tier cake for the party.
Right: She made a two-tier cake for the party.
Casual - Usage: He's on a much-needed vacation this week.

Real usage and tone: when to be strict and when to relax

In formal writing, prefer conservative hyphenation to reduce ambiguity. In chat or social posts, readers often tolerate dropped hyphens, but avoid omissions that create a real misread (e.g., "small business owner" vs "small-business owner").

Formal: always hyphenate adjectival compounds before nouns.
Emails: hyphenate when omission would confuse meaning.
Chat/text: prioritize speed, but add hyphens for tricky phrases (age, step-by-step).

Usage: Formal: The long-term implications were detailed in the executive summary.
Usage: Casual: In a quick text, "five star" is often fine, but in an email prefer "five-star".

Memory trick to find missing hyphens

Use the swap test: move the suspected modifier after the noun. If the sentence still works unchanged, you probably don't need a hyphen. If the phrase only makes sense as a single idea before the noun, hyphenate.

Swap test: "a well known author" → "the author is well known" (no hyphen needed when after the noun).
Number rule: if a number modifies a noun (age, measurement, rating) and comes before the noun, hyphenate: "a 3-week trial" vs "the trial lasted 3 weeks".
If unsure, hyphenate in formal writing; it's safer than risking ambiguity.

Similar mistakes to watch for

Watch closed compounds (email vs e-mail), incorrect apostrophes, and inconsistent hyphenation across a document. Often the solution is consistency: pick a standard and stick with it.

Closed vs hyphenated: "email" is now common; follow your style guide.
Apostrophe ≠ hyphen: don't use an apostrophe where a hyphen belongs.
Consistency matters: don't alternate "long-term" and "long term" in one document.

Usage: Many guides prefer "email" over "e-mail" now.
Usage: Watch: "students records" (ambiguous) vs "students' records" (possession) vs "student-records" (compound modifier).

FAQ

When should I hyphenate numbers like twenty-one or 21-year-old?

Hyphenate number-word compounds used as adjectives before nouns: "a 21-year-old intern" or "a twenty-one-year-old student". If the age follows the noun, no hyphen: "The intern is 21 years old."

Is it "five-star" or "five star" in a review?

Use "five-star" when the phrase modifies a noun ("a five-star review"). In short labels or casual posts "five star" may appear, but in running text hyphenation avoids misreading.

Should I use a hyphen or dash for page ranges?

Use an en dash (-) with no spaces for ranges: "pages 10-12" or "1999-2003". If you can't type an en dash, a hyphen without spaces ("10-12") is an acceptable fallback; avoid spaces around the mark.

How do I check hyphenation across a long document quickly?

Search for patterns like " year old", "step by step", "five star", and numbers followed by units. Use grammar tools that flag missing hyphens, then review suggestions for context.

Are hyphen rules different in American and British English?

Differences are minor-some compounds are more commonly closed in American English. The core rules are the same: hyphenate adjectival compounds before nouns and hyphenate number-word adjectives. Follow the style guide required for your audience.

Check one sentence now

Paste a sentence that looks off into a quick checker and watch for number phrases and compound modifiers. Fixing one hyphen can remove ambiguity and make your writing look more professional.