Official Style Guides and Writing References
The official style organisation is the final authority. Purdue OWL is a reliable free summary. Check the edition your course requires.
Updated 21 October 2026 · EssayWriting.com editorial team
- The official style organisation is the final authority.
- We compare 8 tools on who they help, features and limitations.
- Price labels appear only where the tool’s homepage confirms them.
Official Style Guides and Writing References: quick comparison
| Tool | Best for | Free or paid |
|---|---|---|
| Purdue OWL | Students needing free writing and citation guidance | Check site |
| APA Style (official) | Students using APA | Check site |
| MLA Style Center (official) | Students using MLA | Free |
| Chicago Manual of Style Online | Students using Chicago or Turabian | Free and paid plans |
| Bluebook (official) | US law students | Free and paid plans |
| AMA Manual of Style | Medical and health students | Check site |
| IEEE Author Center | Engineering and computer science students | Paid plans |
| ACS Guide to Scholarly Communication | Chemistry students | Check site |
"Free or paid" is shown only when the tool’s own homepage states it; otherwise check the site. These are independent picks, not affiliate links.
1. Purdue OWL
Free university writing lab guides to APA, MLA, Chicago and essay types
- Who it helps: Students needing free writing and citation guidance.
- Key features: Guides to APA, MLA, Chicago and writing processes.
- Limitations: Check the edition matches what your course requires.
2. APA Style (official)
Official APA Style guidance and samples
- Who it helps: Students using APA.
- Key features: Official APA 7 guidance, examples and sample papers.
- Limitations: Official rules, but some content is in the paid manual.
3. MLA Style Center (official)
Official MLA style guidance and FAQs
- Who it helps: Students using MLA.
- Key features: Official MLA 9 guidance and Q&A.
- Price: Free (as stated on its homepage).
- Limitations: The full handbook is a paid book.
Visit MLA Style Center (official) ↗
4. Chicago Manual of Style Online
Official Chicago/Turabian style reference
- Who it helps: Students using Chicago or Turabian.
- Key features: Official Chicago 18 Q&A and quick guides.
- Price: Free and paid plans (as stated on its homepage).
- Limitations: Full manual requires a subscription.
Visit Chicago Manual of Style Online ↗
5. Bluebook (official)
Official Bluebook legal citation guide
- Who it helps: US law students.
- Key features: Official Bluebook rules.
- Price: Free and paid plans (as stated on its homepage).
- Limitations: Full access is paid.
6. AMA Manual of Style
Official AMA style manual
- Who it helps: Medical and health students.
- Key features: Official AMA style.
- Limitations: Full access requires subscription or institutional access.
7. IEEE Author Center
Official IEEE author and reference guidance
- Who it helps: Engineering and computer science students.
- Key features: Official IEEE reference and author guidance.
- Price: Paid plans (as stated on its homepage).
- Limitations: Written for journal authors.
8. ACS Guide to Scholarly Communication
Official ACS style guide
- Who it helps: Chemistry students.
- Key features: Official ACS guidance.
- Limitations: Full access may require institutional access.
Visit ACS Guide to Scholarly Communication ↗
Related guides
Frequently asked questions
Is Purdue OWL official?
No, it is a respected university resource summarising the official guides.
Which edition of APA is current?
APA 7 (2019).
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