If you receive a high percentage on your Turnitin report, there may be a valid reason, so it’s best not to panic.
The percentage is the amount of text in your paper that has been matched to other sources. Remember this tool only matches text; it does not make any decisions about whether the matched text is plagiarism or not. Text matching can occur for many valid reasons (such as including the question in your paper, correctly quoting a source or correctly referencing a source), so a percentage of 0% matching is rare. There is also no real threshold percentage where one can say the level of text matching is acceptable or not. The determination of what is plagiarism and what is not, is a human decision, not a numerical one.
We recommend that you interpret each individual match, with the view to determining whether the matched text constitutes plagiarism or not.
If you wish to improve your work and resubmit another DRAFT to generate another report, you can do so. However, only one (1) report can be generated on any single draft box within a 24 hour period and one (1) report on any single assignment box within a 24 hours period. So submitting a draft assignment to the draft box does not preclude you from making a final assignment submission, as each box will generate separate reports within a 24 hour period.
For more information on how to interpret your Turnitin report, visit the interpreting the text-matching report FLO page. (Please note: you will need to be logged into FLO to access this link).