1PaperFree: provides free duplicate checking service, and can also receive free duplicate checking words through activities, and also provides online manuscript revision, machine weight reduction and other functions.
2Papertime: You can test once for free, and you can get repeated words for free through the official website activity.
3PaperDay: provide the standard version of free duplicate checking service.
4PaperYY: The first draft can be viewed once a day, and the flagship version can be viewed twice a day.
5PaperOk: Send the word 1w to the registered account for duplicate checking.
In addition, there are many other free duplicate checking software. You can choose the right software to check the duplicate according to your own needs and preferences. It should be noted that different software may provide different services and accuracy, so you need to choose the right software according to your own needs.