Why and when to cite
- Direct quotations: someone's exact words, in quotation marks.
- Paraphrases and summaries: someone's ideas in your own words still need a citation.
- Facts and data that are not common knowledge, such as a statistic from a study.
- Images, charts and tables you did not make.
Citing lets readers check your evidence and gives credit to the people whose work you used. Leaving it out, even by accident, can count as plagiarism under school rules.
MLA vs APA at a glance
| Feature | MLA | APA |
|---|---|---|
| Usually used in | English, languages, humanities | Psychology, sciences, social sciences |
| In-text citation | Author and page: (Rivera 42) | Author and year: (Rivera, 2021); with a quote, add the page: (Rivera, 2021, p. 42) |
| Source list title | Works Cited | References |
| Author names in the list | Full first name: Rivera, Ana. | Initials: Rivera, A. |
| Where the date goes | Near the end of the entry | Right after the author, in parentheses |
| Titles of books and webpages in the list | Capitalize major words, italicize: The Ocean Floor | Capitalize only the first word and proper nouns, italicize: The ocean floor |
One book, both styles
These examples use a made-up source for practice: a book by Ana Rivera called The Ocean Floor, published by Harbor Press in 2021.
| Style | Source list entry | In-text citation |
|---|---|---|
| MLA | Rivera, Ana. The Ocean Floor. Harbor Press, 2021. | (Rivera 42) |
| APA | Rivera, A. (2021). The ocean floor. Harbor Press. | (Rivera, 2021) or (Rivera, 2021, p. 42) for a quotation |
One webpage, both styles
Made-up source: an article by Ana Rivera titled "How Coral Reefs Grow" on the site Ocean Notes, published March 12, 2024, at https://www.example.org/coral-reefs.
| Style | Source list entry |
|---|---|
| MLA | Rivera, Ana. "How Coral Reefs Grow." Ocean Notes, 12 Mar. 2024, www.example.org/coral-reefs. |
| APA | Rivera, A. (2024, March 12). How coral reefs grow. Ocean Notes. https://www.example.org/coral-reefs |
Worked examples
Example 1: cite a paraphrase in MLA
Problem On page 42, Rivera explains that deep-sea vents support life without sunlight. You write that idea in your own words in an English essay.
- Paraphrase in your own words: Some deep-sea animals live near vents that give off heat and chemicals instead of relying on sunlight.
- Add the MLA in-text citation with the author and page, before the period.
- Make sure the book appears in your Works Cited list.
Answer Some deep-sea animals live near vents that give off heat and chemicals instead of relying on sunlight (Rivera 42).
Example 2: the same idea in APA
Problem Now the paragraph is for a science report that uses APA.
- APA uses the author and year. Page numbers are needed for direct quotes and are encouraged for paraphrases.
- You can name the author in the sentence, then put the year right after the name.
Answer Rivera (2021) explains that some deep-sea animals depend on heat and chemicals from vents rather than sunlight.
Common mistakes and fixes
| Mistake | Fix |
|---|---|
| Citing only direct quotes | Paraphrases and borrowed facts need citations too. |
| Mixing styles ((Rivera, 42) or (Rivera 2021, 42)) | Pick one style: MLA (Rivera 42) or APA (Rivera, 2021, p. 42). |
| A source in the text but missing from the list | Every in-text citation must match an entry in Works Cited or References. |
| Trusting a citation generator blindly | Check its output against Purdue OWL or the official style site. Generators often get capitalization and dates wrong. |
| Using an old edition's rules | Use MLA 9 and APA 7, unless your teacher says otherwise. |
Practice
Five citation questions
In MLA style, which in-text citation is correct for page 42 of a book by Ana Rivera?
- (Rivera, 42)
- (Rivera, 2021, p. 42)
- (Rivera 42)
- (Ana Rivera page 42)
Show answer
Answer: (Rivera 42)
MLA uses the author's last name and the page number with no comma between them. (Rivera, 2021, p. 42) is APA style, and the other two add a comma or extra words.
In APA style, what goes in a basic in-text citation for a paraphrase?
- The author's full name and the page
- The author's last name and the year
- The title and the publisher
- Only the page number
Show answer
Answer: The author's last name and the year
APA is an author and date style: (Rivera, 2021). A page number is added for direct quotations. Titles and publishers go in the References list.
What is the list of sources at the end of an APA paper called?
- Works Cited
- References
- Bibliography
- Sources Used
Show answer
Answer: References
APA calls it References. Works Cited is the MLA name. Bibliography is used in other styles such as Chicago's notes and bibliography system.
Which entry is formatted in APA style?
- Rivera, A. (2021). The ocean floor. Harbor Press.
- Rivera, Ana. The Ocean Floor. Harbor Press, 2021.
- Rivera, A. The Ocean Floor, 2021, Harbor Press.
- (Rivera 42)
Show answer
Answer: Rivera, A. (2021). The ocean floor. Harbor Press.
APA uses initials, puts the year in parentheses after the author, and capitalizes only the first word of the title. Rivera, Ana. The Ocean Floor. Harbor Press, 2021. is MLA, Rivera, A. The Ocean Floor, 2021, Harbor Press. mixes styles, and (Rivera 42) is an MLA in-text citation.
When do you need to cite a source?
- Only when you quote it word for word
- Only when the quotation is longer than a page
- Whenever you use its words, facts or ideas, including paraphrases
- Only when your teacher uses APA
Show answer
Answer: Whenever you use its words, facts or ideas, including paraphrases
Both MLA and APA require citations for quotations, paraphrases and borrowed facts or ideas. Length and style choice do not change that.
Frequently asked questions
Which style should I use, MLA or APA?
The one your teacher or assignment asks for. As a rule of thumb, English and humanities classes use MLA, and science, psychology and social science classes use APA. If the assignment does not say, ask, then use one style consistently from start to finish.
Is there an MLA 10 or APA 8?
Not as of October 2026. The current editions are the MLA Handbook, 9th edition (2021), and the Publication Manual of the American Psychological Association, 7th edition (2019). Some websites describe newer editions that have not been released, so check the official sites, style.mla.org and apastyle.apa.org.
Do I need to cite an AI tool I used?
Follow your school's rules first: many classes limit or ban AI help. Both MLA and APA have published guidance on how to cite generative AI on their official sites. Ducky is built to help you understand your sources, not to write for you; see AI use and academic integrity.
What counts as common knowledge?
Facts most people know or can find in many general sources without dispute, like The Pacific is the largest ocean. Specific numbers, recent findings, and anyone's opinions or interpretations are not common knowledge. When in doubt, cite.
Sources
- Purdue OWL, MLA General Format, accessed October 1, 2026
- Purdue OWL, MLA Works Cited: Electronic Sources, accessed October 1, 2026
- Purdue OWL, APA In-Text Citations: The Basics, accessed October 1, 2026
- Purdue OWL, APA Reference List: Basic Rules, accessed October 1, 2026
- Purdue OWL, APA Reference List: Electronic Sources, accessed October 1, 2026
- MLA Style Center (Modern Language Association), accessed October 1, 2026
- APA Style (American Psychological Association), accessed October 1, 2026
