What Turnitin Similarity Score Is Acceptable for a TMA?

“My Turnitin score is 28%. Will I fail?” It is one of the most common worries students bring to us before a TMA deadline. The honest answer is that the number on its own tells you very little. Turnitin does not decide whether you plagiarised; your tutor and your university do, by looking at what the matches actually are.

This guide explains how the Turnitin similarity score works, what different ranges usually mean, and how to read your report so you can fix genuine problems. It is about text matching only. If your concern is that your TMA has been flagged as AI-written, that is a separate issue covered on our Turnitin AI flag help page.

What does the Turnitin similarity score actually measure?

The similarity score is the percentage of your submission that matches or closely resembles text in Turnitin’s databases. Those databases include web pages, published material and previously submitted student work.

That is all it measures. It does not know whether a matched passage is a properly referenced quotation, a common phrase, your reference list, the question text you copied into your answer, or copied work. A 30% score made up of quotations and references is very different from a 10% score that comes from one unreferenced paragraph taken from a website.

Turnitin’s own guidance makes the same point: the report shows matching text, and judging whether that amounts to plagiarism is a matter of academic judgement.

Is there an acceptable Turnitin similarity score for a TMA?

There is no universal “safe” percentage. Universities and tutors generally say there is no ideal score, because what is normal depends on the type of assignment, its length and how much quotation or technical language it needs.

Some patterns are common:

• A short reflective TMA in your own words will usually have a low score.
• A law TMA quoting statutes, or a TMA that must reproduce a set question or template, may score higher without any problem.
• A score of 0% is not automatically good. It can simply mean nothing matched, which is normal, but it is not a target.

If a number circulates among your classmates as “the limit”, treat it with caution. Unless your module guide or course page states a threshold, your tutor will look at the matches, not just the total. If your module does state one, follow it.

What do the colours on a Turnitin similarity report mean?

Turnitin shows the overall score with a colour band. The bands simply group the percentage; they are not grades or verdicts.

Colour	Similarity range	What it usually suggests
Blue	No matching text	Nothing matched the databases
Green	One word up to 24%	The most common range; still check individual matches
Yellow	25–49%	Worth reviewing what is driving the matches
Orange	50–74%	A large share of text matches; needs careful review
Red	75–100%	Most of the text matches, for example a resubmitted or copied file

Even within green, one large match from a single source can be a problem. Within yellow, a long reference list and many short quotations can be perfectly fine. Always open the report.

How do I read my similarity report line by line?

If your university lets you see the report, work through it in this order:

1. Check the source list. Is the score spread across many sources at 1% each, or is one source responsible for a big chunk? A single large source is the first thing to investigate.
2. Look at each highlighted passage. Is it a quotation in quotation marks with a reference? A reference list entry? A common phrase or technical term? Text from the TMA question itself?
3. Find the risky matches. Long passages without quotation marks, sentences that follow a source closely with a few words changed, or text from a classmate or an earlier submission.
4. Check matches to your own earlier work. If you are resubmitting a module, reusing your old TMA may count as self-plagiarism. Check your university’s rules.

Your tutor may use filters to exclude quoted text, bibliographies or very small matches. You may not see those filters applied in your own view, so do not panic if your score looks higher than you expected.

Why might my Turnitin score be high even if I did not copy?

A high score without wrongdoing is common. Typical reasons include:

• Reference lists. Other students cite the same textbooks and module materials.
• Quotations. Correctly quoted and referenced, but still matched.
• Question text and headings. Copying the TMA question or a required template into your answer.
• Standard phrases and terminology. Definitions, legal tests, model names and set phrases in your subject.
• Your own draft. If you submitted a draft to the same assignment and it was stored, your final version may match it. Check your university’s settings and guidance on draft submissions.

None of these is plagiarism in itself. What matters is that every borrowed idea and phrase is properly referenced.

How can I lower a Turnitin similarity score the right way?

The aim is not to beat a number. It is to make sure the work is genuinely yours and correctly referenced. That will usually lower the score as a side effect.

• Reduce long quotations. Quote only when the exact wording matters. Otherwise, explain the idea in your own words and reference it.
• Paraphrase properly. Read the source, close it, write the idea from your understanding, then check you have not followed its sentence structure. Swapping a few synonyms is still too close.
• Add your own analysis. Comment on what the source means for your argument. Analysis is always original, and it is where the marks are.
• Fix referencing. Every quotation needs quotation marks and a citation; every paraphrase needs a citation. Our guides to APA 7 for SUSS TMAs and Cite Them Right Harvard for OU TMAs show the formats.

Never use paraphrasing tools or “word spinners” to disguise matched text. They often produce awkward or wrong meaning, tutors can usually spot them, and they may breach your university’s rules on generative AI and academic conduct.

Do SUSS and the Open University use Turnitin for TMAs?

SUSS uses Turnitin. Several universities have also stopped relying on Turnitin’s AI writing score and focus instead on whether students understand and own their work; text matching is a separate feature, so check which reports your course actually uses. Whether you can see your own similarity report, and whether you can resubmit before the deadline, depends on how each course sets up its submission. Check your course guide or Canvas page.

The Open University offers Turnitin to support students in developing academic literacy skills, but not every assignment is suitable for it, and arrangements differ between modules. Your module website will tell you whether and how it applies to your TMAs.

For Malaysian, Australian and Gulf universities, practice varies again. If you are unsure, ask your tutor how similarity checking is used on your course.

What should I do if my tutor raises a concern about matching text?

A query about similarity is not the same as a finding of plagiarism. Stay calm and respond promptly. Practical steps:

• Read the message carefully. Note exactly which passages or sources the tutor mentions, and any deadline for a reply.
• Gather your evidence. Notes, earlier drafts, file version history and the sources you used can all show how your work developed.
• Be honest. If a passage was poorly referenced, say so and explain how it happened. Mistakes in referencing are usually treated differently from deliberate copying.
• Check your university’s procedure. SUSS, the OU and other universities each publish academic conduct procedures, and many have student advice services that can support you.

Most importantly, learn from it for the next TMA. Build referencing into your drafting rather than adding it at the end, when it is easy to lose track of which ideas came from where.

When should I ask someone to look at my similarity report or draft?

If your report shows a large match you do not understand, or you are not confident your paraphrasing and referencing are right, getting a tutor’s view before the deadline is far easier than dealing with an academic conduct query afterwards. Our TMA draft review looks at a draft you have written and gives feedback on referencing, paraphrasing and structure so you can make the changes yourself. We never promise a particular score, and the work you submit must remain your own under your university’s rules.