Every proofreader learns the marks. Whether you trained with the Chicago Manual of Style, the BSI standard (BS 5261), or a modern online course, proofreading marks are the shared language between the person who spots the error and the person who fixes it.
But here’s the thing — that language is changing. Fast.
This guide covers both worlds: the traditional symbols you’ll find in style manuals, and the modern plain-language annotations that most working proofreaders actually use today. Bookmark it. You’ll need it.
The Traditional Marks
These symbols have been used for over a century. They were designed for a world where a proofreader marked up a paper proof with a red pen, and a compositor (later a typesetter) interpreted those marks to make corrections.
Deletion & Insertion
| Mark | Name | Meaning | Usage |
|---|---|---|---|
| ✗ (with a loop) | Dele | Delete text | Draw through the unwanted text and write ✗ in the margin |
| ‸ | Caret | Insert text | Place at the insertion point; write the missing text in the margin |
| ⌇ (vertical line) | Delete and close up | Remove character, close the gap | Used for removing a letter within a word |
Dele is probably the most recognisable proofreading mark. It comes from the Latin delere — to destroy. You’ll see it rendered as a looped cross (sometimes resembling a lowercase d with a tail) in the margin, paired with a strike-through in the text.
Caret (from Latin caret, “it is lacking”) marks where something needs to be added. In practice, you place the caret in the text and write the insertion in the nearest margin.
Case Changes
| Mark | Name | Meaning |
|---|---|---|
| ≡ (triple underline) | Capitalise | Change to uppercase |
| / (diagonal stroke) | Lowercase | Change to lowercase |
| ═ (double underline) | Small caps | Set in small capitals |
Triple underline beneath a letter means “make this a capital.” A single diagonal stroke through a capital letter means “make this lowercase.” Simple in theory — but in a 200-page manuscript, these marks add up fast.
Spacing & Position
| Mark | Name | Meaning |
|---|---|---|
| # | Insert space | Add a space between characters or words |
| ⌢ (a curved line) | Close up | Remove unwanted space |
| ¶ | New paragraph | Start a new paragraph |
| ⤺ (run-on mark) | Run on | No new paragraph — continue on same line |
| ↕ | Transpose | Swap the order of two adjacent elements |
The paragraph mark (¶, also called a pilcrow) is one of the oldest typographical symbols, dating back to medieval manuscripts. In proofreading, it simply means “break here — start a new paragraph.”
Transpose is marked in the text by drawing a curved line that swaps two elements, with “tr” or “trs” written in the margin.
Typography & Formatting
| Mark | Name | Meaning |
|---|---|---|
| _____ (single underline) | Italic | Set in italic |
| ~~~~ (wavy underline) | Bold | Set in boldface |
| Circled text | Keep as-is / query | Various uses depending on context |
| stet (with dots below) | Stet | ”Let it stand” — ignore the previous correction |
Stet is the proofreader’s undo button. Derived from the Latin for “let it stand,” you use it when a correction was marked in error. Underline the original text with dots and write “stet” in the margin.
Punctuation
| Mark | Meaning |
|---|---|
| ⊙ | Insert full stop (period) |
| ⊘ | Insert colon |
| ∧ with comma | Insert comma |
| ∧ with semicolon | Insert semicolon |
| ⊘⊘ | Insert quotation marks |
| ─ | Insert hyphen |
| ── | Insert en-dash |
| ─── | Insert em-dash |
In traditional marking, punctuation insertions are indicated at the point of insertion with a caret, and the specific punctuation is drawn in the margin — often circled to distinguish it from text insertions.
BSI Marks (BS 5261)
If you work in British publishing, you’ll encounter BS 5261 — the British Standards Institution’s specification for proofreading marks. These are broadly similar to the Chicago/American marks but with some differences in notation.
Key BSI conventions:
- Marginal marks are essential. Every in-text mark must have a corresponding marginal instruction.
- A vertical line in the margin separates multiple corrections on the same line.
- New matter (inserted text) is followed by a closing slash (/) in the margin.
- Marks are placed in the nearest margin (left or right) to where the correction occurs.
BSI marks are still taught in some UK publishing courses and are used by editors working with traditional publishers. However, even in British publishing, their use has declined significantly since the shift to digital workflows.
Where BSI Marks Still Live
- Traditional UK publishers (especially academic and literary presses)
- Some freelance proofreaders who trained before ~2010
- Proofreading courses that teach “both methods” (digital and traditional)
Louise Harnby, a well-known editorial trainer in the UK, has created downloadable PDF stamp sets based on BSI marks — a nod to the fact that some proofreaders want to use traditional symbols in digital tools. If that’s your workflow, you can recreate these as custom stamps in any annotation app.
The Modern Approach: Plain-Language Annotations
Here’s what most working proofreaders actually do in 2026:
They write what they mean.
Instead of drawing a dele mark, they highlight text and write “Delete.” Instead of using a caret and writing in the margin, they drop a comment that says “Insert: the.” Instead of triple underlining, they type “Capitalize.”
This shift happened for three reasons:
-
Digital tools changed the workflow. PDF annotations, comments, and tracked changes replaced red pen on paper. The old symbols were optimised for pen — they’re clunky with a stylus or keyboard.
-
Collaboration crossed borders. A British proofreader using BSI marks and an American editor using Chicago marks might work on the same document. Plain language is universal.
-
Training changed. Major proofreading courses (like Knowadays, formerly Proofread Anywhere) teach plain-language annotation. A new generation of proofreaders never learned the traditional symbols.
The Modern Mark Set
These are the annotations you’ll see most working proofreaders use today:
| Annotation | What It Means | When to Use It |
|---|---|---|
| Check Spelling | Query a word — is this correct? | Ambiguous spellings, proper nouns, technical terms |
| Capitalize | Change to uppercase | Missing capital at sentence start, proper nouns |
| Lowercase | Change to lowercase | Incorrect capitalisation |
| Add Punctuation | Missing period, comma, etc. | Spoken-to-text content, run-on sentences |
| Delete | Remove this text | Redundant words, repeated phrases |
| Insert: [text] | Add the specified text | Missing words, missing articles |
| Transpose | Swap the order | Adjacent words in wrong order |
| Clarify | Meaning is unclear | Ambiguous phrasing, inaudible audio-to-text |
| Stet | Ignore previous mark | When a correction was made in error |
| Spell Out | Expand abbreviation | ”Mr.” → “Mister”, “approx.” → “approximately” |
| Hyphenate | Add a hyphen | Compound words: “cross-examination” |
| Format | Change layout | Paragraph breaks, heading levels, indentation |
| Verify | Fact-check this | Dates, statistics, quotes, citations |
The key difference? Any literate person can read these. A court reporter, a self-publishing author, a law firm partner — they don’t need to know what ✗ with a loop means. They read “Delete” and they delete.
Traditional vs Modern: When to Use Which
There’s no right answer — it depends on who you’re working with.
Use traditional marks when:
- Your client or publisher specifically requires them
- You’re working within a house style guide that mandates BSI or Chicago marks
- You’re proofreading for a traditional UK publisher
Use modern annotations when:
- You’re working on PDFs (most common scenario in 2026)
- Your client is not a professional editor (authors, businesses, legal teams)
- You want your annotations to be immediately clear without a reference guide
- You’re proofreading court transcripts or legal documents
The trend is clear: plain language is winning. But traditional marks aren’t dead — they’re just increasingly niche. Knowing both gives you flexibility.
Going Digital: Proofreading Marks on iPad and PDF
The biggest shift in proofreading workflow isn’t which marks you use — it’s how you apply them.
On paper, you drew marks in the margin. On a PDF, you have options:
- Comments and annotations — the most common approach. Select text, add a comment.
- Drawing tools — freehand marks with a stylus. Flexible but messy.
- Stamps — pre-made annotation marks you can tap and place. Fast, consistent, professional.
The stamp approach is particularly powerful for proofreaders who process high volumes of documents. Instead of typing “Delete” into a comment box fifty times a day, you tap a stamp. Instead of drawing a freehand circle and writing “Check Spelling,” you tap a stamp.
Stampede was built around this idea. It puts a customisable stamp sidebar alongside your PDF — each stamp is an annotation you can place with a single tap. You can use the built-in set (based on modern plain-language marks) or create your own stamps for any workflow, including traditional BSI symbols if that’s what your work requires.
The point isn’t to impose a system. It’s to make your system faster.
Quick Reference Card
Here’s everything on one table — old and new, side by side:
| What You Want to Do | Traditional Mark | Modern Annotation |
|---|---|---|
| Delete text | ✗ (dele) | Delete |
| Insert text | ‸ (caret) + marginal note | Insert: [text] |
| Change to uppercase | ≡ (triple underline) | Capitalize |
| Change to lowercase | / (stroke through letter) | Lowercase |
| Start new paragraph | ¶ (pilcrow) | New paragraph |
| Continue (no break) | ⤺ (run-on) | Run on |
| Swap order | ↕ + “tr” | Transpose |
| Leave unchanged | stet (with dots) | Stet |
| Set italic | Single underline | Italicise |
| Set bold | Wavy underline | Bold |
| Add space | # | Add space |
| Remove space | ⌢ (close up) | Close up |
| Query spelling | Circle + ”?” | Check Spelling |
| Expand abbreviation | Circle + “sp” | Spell Out |
| Add hyphen | ─ in margin | Hyphenate |
| Meaning unclear | ”?” in margin | Clarify |
| Check a fact | — | Verify |
The Marks Are Just the Beginning
Knowing proofreading marks — whether traditional or modern — is table stakes. What separates a fast, accurate proofreader from a slow one isn’t knowledge of symbols. It’s workflow.
How quickly can you move through a document? How consistently do you apply your marks? How easily can the person receiving your annotations understand them?
That’s what good tools solve. Not what to mark — but how to mark it efficiently, consistently, and clearly.
Whatever marks you use, make them work for you.