Most paper duplicate checking systems need to be paid. Some mainstream duplicate checking websites include HowNet, VIP, Wanfang and paperfree. These websites usually have free duplicate checking opportunities, but the number of times is limited. Other relatively small paper duplicate checking websites, such as Papertime and paperday, can also check duplicates for free. They are all regular duplicate checking websites, so you can use them with confidence.

The price of paper duplicate checking varies with different duplicate checking systems. Generally speaking, the prices of HowNet and Victoria Census are relatively high. The price of undergraduate thesis is about 200~300 yuan, the price of master thesis is about 300 yuan, and the price of professional periodical thesis is about 50~55 yuan. The paper prices of Wanfanghe Paper Series are relatively low, basically between 1.5 yuan/Qianzi -2.0 yuan/Qianzi, and many of them can be searched for free.

If you need to check the duplicate several times, you can find some websites that provide free duplicate checking opportunities, such as regular duplicate checking software such as paperfree and papertime. PaperFree's online duplicate checking function can modify the paper while checking the duplicate, and check the duplicate wherever you change it. According to the actual modified sentences, there is no charge for the content that is not changed.