Litimus vs Turnitin
Turnitin’s AI Writing Report sits inside a platform many schools and universities already use. Litimus is a standalone tool that anyone can use without an institution. They are not really substitutes, and the numbers they show do not mean the same thing.
The short version. If your institution uses Turnitin, its report is the one your institution’s process will refer to, and it also covers similarity checking. Litimus is for people outside that workflow: a student checking a draft, a teacher without a licence, an editor or a freelancer. It does not replace Turnitin and does not try to match it.
Side by side
| Turnitin AI Writing Report | Litimus | |
|---|---|---|
| Who can use it | Access depends on your institution’s licence and settings. Turnitin’s guidance is written for instructors. | Anyone. A free scan needs no account. |
| What the number means | The percentage of “qualifying text” (prose sentences in long-form writing) that the system believes may have been generated by AI tools or altered by AI paraphrasing software. | A likelihood score for the whole passage, shown as “% AI-likely” and grouped into three bands: 66 and above AI-likely, 34 and below human-likely, and 35 to 65 mixed / unclear. |
| Low scores | Scores from 1% to 19% are not shown as a number. The report shows an asterisk, to reduce false positives. | Every score is shown. Middle scores are labelled mixed / unclear rather than hidden. |
| Length and files | 300 to 30,000 words. Accepts .docx, .pdf, .txt and .rtf, up to 100 MB. | Scores from 8 words and flags anything under 25 words as too short for a stable read. Free scans cover 2,000 words a day. Paid plans add .docx and .pdf. |
| Languages | Detects English, Spanish, Japanese and Arabic. Paraphrase detection works in English only. | Tuned for English. |
| Stated false-positive aim | Says it targets a false positive rate below 1%, and that a small risk remains. | No rate published. The report and the Terms state that a score is a probability, not proof. |
| Plagiarism checking | Turnitin is best known for similarity checking. The AI Writing Report is a separate report. | None. Litimus does not compare text against sources. |
The two numbers are not the same thing
A Turnitin score of 40% describes how much of the qualifying text the system flagged. A Litimus score of 40 describes how likely the whole passage is to be machine-written, and it falls in the mixed / unclear band. The two answer different questions, so do not read one as a translation of the other, and do not average them.
Where Turnitin is the better choice
- Your institution already uses it. Its report lives in the submission workflow and its status under your institution’s policy is defined. Nothing outside that workflow carries the same standing.
- You need more than English. Turnitin lists detection in English, Spanish, Japanese and Arabic.
- You need similarity checking too. Litimus does not check for plagiarism.
Where Litimus is the better choice
- You are outside an institution, or your institution does not give you access. A student cannot always run a draft through the same report their instructor will see, and Litimus lets you check your own writing before you hand it in.
- You want the reasoning laid out. The report shows readings for sentence rhythm, vocabulary spread, stock phrases and repeated phrases, and quotes the phrases it found.
- You want a second opinion, not a replacement. If a score surprises you, looking at the same text in a different tool can add context. It is never proof either way.
What Turnitin itself says about its scores
Turnitin’s guidance says AI writing detection “may not always be accurate” and should not be used as the sole basis for adverse action against a student. Its own article on false positives advises educators to assume positive intent and to talk with the student about the findings. Litimus’s Terms of Service ask the same of you. If you are on the receiving end of a score, read what to do if you are falsely accused.
Sources
Facts about Turnitin come from its published guidance as we read it on the date above. Institutions can configure it differently, so check with yours.