You have probably seen both “appendices” and “appendixes” at the end of books and reports and wondered which one is correct. The truth is, both forms exist in real English — and that is exactly where the confusion begins.
Maybe your teacher wrote “appendices,” but your friend typed “appendixes.” Your spellchecker accepts both, so neither looks wrong. Do not worry — this is one of the easiest confusions to fix, and this guide will settle it for good.
First Things First: What Does “Appendices” Mean?
Appendices is the traditional plural of appendix — an extra section at the end of a book or document that holds supporting material like tables, charts, or raw data that would disturb the main text.
Appendices: the classic plural of “appendix” — extra sections at the end of a book or document.
Where You See Appendices in Real Life
- School textbooks, with extra maps and charts
- Research papers, holding raw survey data
- Company reports, with detailed financial tables
- Instruction manuals, with troubleshooting lists
Why Appendices Matters
- It keeps the main text clean and easy to read
- It gives readers all extra details in one place
- It is the form teachers and editors expect to see
For formal writing, appendices is almost always the safer choice.
Now, What Is “Appendixes”?
Appendixes is the modern, regular plural of “appendix.” English usually adds -es to words ending in x (box → boxes, tax → taxes), and “appendixes” simply follows that normal rule. The meaning is exactly the same as “appendices.”
Appendixes: the regular modern plural of “appendix” — same meaning, simpler spelling rule.
The Idea Behind Appendixes
- It follows the standard English plural rule for words ending in x
- It feels natural and simple to modern readers
- It is fully accepted by major dictionaries
Think of “appendixes” as the everyday, no-fuss version of the same word.
Real-Life Example
Imagine you finish a college project and add your interview notes at the very end:
- Your professor writes: “Move these notes to the appendixes.”
- A classmate asks: “How many appendixes does your report have?”
- Both sentences are perfectly correct English.
Why People Confuse Appendices and Appendixes
The confusion is completely natural, and here is why:
- Both words mean exactly the same thing
- They differ by only a few letters in the middle
- One follows Latin rules, the other follows normal English rules
- Spellcheckers accept both forms, so neither looks wrong
Appendices vs Appendixes: Side-by-Side Comparison
Here is a clear breakdown to lock it in your mind:
| Feature | Appendices | Appendixes |
|---|---|---|
| Type | Traditional (Latin-style) plural | Modern (regular) plural |
| Meaning | Extra sections at a document’s end | Extra sections at a document’s end |
| Usage | Formal and academic writing | Everyday and modern writing |
| Origin/Spelling | Latin plural pattern (-ices) | Standard English rule (-es after x) |
| Context | Theses, textbooks, official reports | Blogs, emails, casual documents |
| Example | “See Appendices A and B.” | “Check the appendixes below.” |
How to Use “Appendices” Correctly
Use appendices when your writing should sound formal and traditional:
- Academic essays, theses, and research papers
- Official company or government reports
- Published books and textbooks
- Exam answers where formal English is expected
Natural Examples
- “The appendices at the back include helpful maps.”
- “Please refer to Appendices A and B for the raw data.”
- “Her thesis had three appendices with transcripts.”
In serious settings, appendices is the form most readers expect.
How to Use “Appendixes” Correctly
Use appendixes when the tone is modern, simple, or casual:
- Blog posts and online articles
- Work emails and internal documents
- School projects and homework
- Anywhere clarity matters more than tradition
Natural Examples
- “I added two appendixes with extra screenshots.”
- “The appendixes explain the technical steps.”
- “You will find the full list in the appendixes.”
In casual writing, appendixes will never look wrong.
A Simple Trick to Remember the Difference
Here is an easy way to choose between them:
- Appendices = Academic — both start with A, and both feel formal
- Appendixes = boXes — it follows the same simple rule as boxes and taxes
Formal paper → appendices. Casual writing → appendixes.
Where You Might See These Words Online
Appendices (Common Usage)
- University websites and online journals
- Grammar guides explaining Latin plurals
- Official company PDF reports
- Wikipedia references and citations
Appendixes (Niche Usage)
- Blogs with writing tips
- Grammar discussion forums
- Modern style guides
- Student question-and-answer sites
Both appear online, but “appendices” still rules the formal sources.
Interesting Fact You Probably Didn’t Know
English borrowed many Latin plurals centuries ago because educated writers wanted English to look as serious as Latin. That is why we have pairs like “cactus → cacti,” “focus → foci,” and “appendix → appendices” — even though English is not a Latin-based language at all.
But modern English keeps simplifying itself. “Appendixes” shows the language moving toward one easy rule for everyone, a process experts call “regularization.” It already changed words like “dreamed,” which replaced the older “dreamt” in American English.
So when you choose “appendixes,” you are quietly taking part in a centuries-long trend of making English simpler for everyone.
Further reading: Appendices — Merriam-Webster | Appendixes — Cambridge Dictionary
Common Mistakes to Avoid
Let us clear up a few typical errors:
❌ Mixing both forms in one document
Wrong: “See the appendices for data and the appendixes for charts.”
Right: “See the appendices for the data and the charts.”
❌ Using “appendixes” as a singular word
Wrong: “Read the appendixes at the end of the chapter.”
Right: “Read the appendix at the end of the chapter.”
❌ Spelling it “appendicies” with a y
Wrong: “The report has two appendicies.”
Right: “The report has two appendices.”
Pick one plural form per document and stay consistent — that matters more than which one you pick.
Which One Should You Use?
It depends entirely on your audience and setting:
- Writing a thesis, exam, or formal report? → Appendices
- Writing a blog, email, or casual document? → Appendixes
- Not sure who will read it? → Appendices (the traditional form offends nobody)
Final Thoughts
At first glance, appendices and appendixes look like rivals, but they are really just two doors to the same room. One comes from Latin tradition, the other from simple modern logic — and both are fully correct.
The real skill is not memorizing a rule but reading your audience. Formal readers respect tradition, while casual readers value simplicity. Match your word to your reader, and you will always be right.
“Am I writing for a professor… or for a friend?”
That one question will always lead you to the right plural.
