Et Al. Rules Calculator
Enter how many authors a source has, choose a citation style, and see the et al. rule for the in-text citation and the reference list, with an example of each. The tool covers APA 7, MLA 9, Chicago 18 (author-date and notes), Harvard, Vancouver and IEEE. Free, no sign-up, and everything runs in your browser.
APA 7th Edition Rules for 3 Authors
In-text citation rule
1-2 authors: list all. 3+ authors: first author et al.
Reference list rule
List up to 20 authors. For 21+, list first 19, ellipsis, then last author.
Example with 3 authors
In-text citation
(Smith et al., 2024)
Reference list entry
Smith, X., Johnson, X., & Williams, X. (2024). Title of work.
Quick Reference: When to Use Et Al.
| Style | In-Text | Reference List |
|---|---|---|
| APA 7th | 3+ authors | 21+ authors |
| MLA 9th | 3+ authors | 3+ authors |
| Chicago A-D | 3+ authors | 7+ authors |
| Chicago Notes | 3+ authors | 7+ authors |
| Harvard | 4+ authors | List all |
| Vancouver | Numbers only | 7+ authors |
| IEEE | Numbers only | 7+ authors |
How to Use the Et Al. Rules Calculator
- Enter the number of authors. Type a number from 1 to 25. Examples use placeholder surnames (Smith, Johnson, Williams …).
- Choose the style. Pick APA 7th, MLA 9th, Chicago Author-Date, Chicago Notes-Bibliography, Harvard, Vancouver or IEEE.
- Read the two rules. In-text citation rule says when the citation shortens to the first author and et al.; Reference list rule says how many authors the full entry lists.
- Copy the pattern. The examples below show the in-text citation and the reference-list entry for that author count, with et al. highlighted where it appears.
Et Al. Rules by Style
| Style | In the text | In the reference list |
|---|---|---|
| APA 7 | 3 or more authors: first author et al. (Smith et al., 2024) | up to 20 authors listed; with 21 or more, the first 19, an ellipsis, then the last |
| MLA 9 | 3 or more: (Smith et al. 15) | 3 or more: first author, et al. |
| Chicago 18 | 3 or more in notes and author-date citations: (Smith et al. 2024, 15) | up to 6 listed; 7 or more: the first 3, then et al. |
| Harvard (Cite Them Right) | 4 or more: (Smith et al., 2024) | every author listed |
| Vancouver | numbers only | up to 6 listed; 7 or more: the first 6, then et al. |
| IEEE | numbers only | up to 6 listed; 7 or more: the first author, then et al. |
Rules from the APA Publication Manual (7th ed.), the MLA Handbook (9th ed.), The Chicago Manual of Style (18th ed.), Cite Them Right, NLM’s Citing Medicine sample references and the IEEE Reference Guide. Harvard varies by university; AMA 11 is not in the calculator and gives the first three authors before et al. when there are more than six.
Punctuation differs too. APA and Harvard put a comma after et al. in a parenthetical citation, (Smith et al., 2024), while MLA and Chicago do not: (Smith et al. 15). The period after al is always kept because et al. is an abbreviation of et alii, “and others”; et alone takes none. Current APA, MLA and Chicago editions set et al. in roman type, not italics.
Worked Example
Set the author count to 7 and choose Chicago Notes-Bibliography. The in-text line becomes a note, 1. Xavier Smith et al., Title of Work (Publisher, 2024), 15., because notes shorten from three authors. The reference-list rule is “up to 6; 7 or more, first 3 followed by et al.”, so the bibliography entry reads Smith, Xavier, Xavier Johnson, Xavier Williams, et al. Title of Work. Publisher, 2024. Change the count to 6 and the entry lists all six names with no et al.
Now switch to IEEE at 7 authors: the reference becomes [1] X. Smith et al., “Title of work,” Publisher, 2024. — the first author only — while Vancouver at 7 keeps the first six names before et al.
Common Mistakes
- Using one rule for every style. A three-author source is Smith et al. in APA, MLA and Chicago but is named in full in Harvard, which waits until four authors. Check the style, not just the count.
- Shortening the reference list like the text. In APA the in-text citation shortens at three authors but the reference list names up to 20. Always check the two columns separately.
- Forgetting where a rule switches. APA’s reference list changes form at 21 authors, not 20. Enter 20, then 21, to see the ellipsis form appear. The calculator accepts 1 to 25 authors.
- Two sources with the same first author and year. If Smith et al. (2024) could mean two different works, APA asks you to add as many names as needed to tell them apart. The calculator does not test for this.
Frequently Asked Questions
- What does et al. mean?
- Et al. is short for the Latin et alii (masculine) or et aliae (feminine), “and others”. In a citation it stands in for authors you have not named, so the reader can see who leads the work without a long list of names.
- When do you use et al. in APA 7?
- In the text, from the first citation, whenever a source has three or more authors: (Smith et al., 2024). Sources with one or two authors always give every name. In the reference list APA 7 writes out up to 20 authors, so et al. is not used there.
- How many authors before et al. in MLA?
- MLA 9 uses et al. for three or more authors, in the text and in the Works Cited entry: (Smith et al. 15) and Smith, Xavier, et al. For two authors, name both.
- How does Chicago handle et al. in the 18th edition?
- Notes and author-date citations name one or two authors and shorten to the first author plus et al. at three. A bibliography or reference list names up to six authors and, for seven or more, gives the first three followed by et al.
- Is et al. italicized?
- No, not in current APA, MLA or Chicago. It is a common Latin abbreviation set in roman type, and it keeps its period after al.
- Do Harvard, Vancouver and IEEE use et al. differently?
- Yes. Harvard (Cite Them Right) shortens in the text from four authors and lists everyone in the reference list. Vancouver and IEEE number their citations, so et al. appears only in the reference list: after six names in Vancouver and after the first author in IEEE, once there are more than six.
- Which style should I follow if my instructor’s guide differs?
- Your instructor’s or journal’s guide always wins. Harvard in particular is a family of styles, and some journals set their own author limits. The calculator shows the published rules of each style.