How often does Turnitin update its database?

The short answer is literally every single day! The longer answer is that the devil lies in the details. Keep reading to know more about it.

Why Turnitin updates its database daily?

The simple answer is they want to ensure they capture all the newly published web content, student papers, and academic articles to detect plagiarism or AI-generated text. Their aim is that no stone is left unturned. Let’s break it down further:

1. Web Content

   • Turnitin reports crawling tens of millions of webpages per day, and in 2023 they said they crawl ~300 million webpages/day.
   • They add over 50 million new pages daily. That’s 50 million new pages included in their index every day!
   • Total coverage by 2023 is said to be a jaw-dropping 47+ billion current and archived web pages.
   • They also keep older copies (a historical archive) so if a page changes or gets deleted, it’s still there for Turnitin’s system to match against.

2. Student Papers

   • They index new student submissions in real-time or near-real-time. These new papers often appear in the database within minutes.
   • A few years ago, Turnitin’s repository had 1+ billion student papers. By 2023, it’s around 1.9 billion. That’s huge!
   • More than 1 million new student papers get added each day. So your submission likely appears in Turnitin’s index almost immediately.
   • They flag any overlaps—even if you borrowed from a student at a different university or from a previous year—while ignoring genuine self-matches in the same course assignment.

3. Academic Publications

   • Turnitin gets content from nearly 81,000 journals and about 190 million journal articles, conference papers, eBooks, etc.
   • They claim they cover 97% of the world’s top 10,000 journals.
   • They typically grab new issues weekly or sometimes continuously, plus they refresh books and dissertations monthly.

Because Turnitin’s index is dynamic—meaning every day or every week something new gets ingested—your similarity reports can shift if a new source is added to the database that matches your text.

Also Read: Can Turnitin Read Images?

How about Turnitin’s AI content detection updates?

Their database updates match text from trillions of words across web pages, student papers, and academic research. But their AI detection models also get separate improvements every few months:

• April 2023 – Initial AI Detector Launch
  • Introduced an AI “writing percentage” for English text.
  • Some teachers felt the false positives were too high.
• May 2023 – False-Positive Reductions (May 24, 2023)
  • Fixed boundary issues, stopped scanning very short texts under 300 words, added an asterisk for low AI scores (<20%).
  • Claimed false positives dropped below 1% for documents with >20% AI text.
• August 2023 – Expanded Coverage & Minor Bug Fixes (Aug 9, 2023)
  • Consider text in tables and cells.
  • Ignore references or work-cited sections to avoid false alarms.
• December 2023 – Paraphrased AI Detection (Dec 6, 2023)
  • Started detecting AI text that has been paraphrased or spun.
  • Overall AI score remained a single percentage.
• July 2024 – Enhanced AI Report & Threshold Change (Jul 16, 2024)
  • Labels for “direct AI-generated” or “AI-paraphrased.”
  • Word-limit for checking increased to 30,000 words.
  • Any AI percentage under 20% is shown as “*” to avoid confusion.
• September 2024 – Spanish AI Detection (Sept 12, 2024)
  • Introduced a Spanish-language AI detector.
• April 2025 – Japanese AI Detection (Apr 2, 2025)
  • Rolled out a Japanese model specifically for that language.
• August 2025 – Bypass Tactics Detection (Aug 27, 2025)
  • Started labeling paraphrased text manipulated by “bypass” tools.
• October 2025 – Model Accuracy Improvement (Oct 14, 2025)
  • Tuned the AI model to find more AI text while keeping false positives low, for new submissions.

Overall, it’s a cat-and-mouse situation: new AI writing styles emerge, Turnitin updates detection, paraphrasers adapt, and Turnitin fixes more vulnerabilities.

Also Read: Does Turnitin Compare Your Paper Against Paywalled Journals?

Statistical Terms Simplified

• 300 million webpages daily: 300 million distinct addresses on the internet.
• 50 million new pages daily: They expand coverage by 50 million new items.
• 1 million new student papers daily: A million submissions scanned each day.
• Over 1.9 billion total papers: A massive library of existing essays, making undetected copying very unlikely.

Despite all these updates and expansions, if you write genuine, properly cited, original work, you are safe. Authentic writing usually stands on its own. If you want to rewrite it though, you can use Deceptioner's Turnitin mode.

Also Read: Is iThenticate same as Turnitin?

Frequently Asked Questions

Q1. Does Turnitin’s frequent updating mean I can’t rewrite or paraphrase at all?

No. You can do it, but be mindful that Turnitin’s dynamic index is vast and they also detect paraphrased AI content. If your paraphrasing is purely for clarifying your own ideas, you’ll be fine.

Q2. Is Turnitin’s daily web crawl needed to catch plagiarism?

Yes. They keep matching your paper not just with older content but also with any new stuff that emerges on the internet.

Q3. Will Turnitin keep old copies of websites that are changed or deleted?

Yes, they keep historical snapshots. Even if the site gets taken down, Turnitin still has it in its archives.

Q4. Does Turnitin read references or bibliography for AI detection?

Their older version used to scan everything. Now they skip references, footnotes, or bibliography sections to avoid false positives for AI detection.

Q5. Does Turnitin detect manual paraphrase?

It can if you copy large chunks and slightly rewrite them. They also have complex algorithms for AI detection, so proceed with caution.

The Bottom Line

Turnitin keeps its database fresh practically around the clock, adding new online content, research, and student papers all the time. You might pass a check by manual rewriting, but it’s extremely unlikely you’d pass if you copy large sections. Their AI detection is also evolving rapidly. If you stay honest, it doesn’t matter how often they update—you can still sleep well at night.