Free Grammar Checker
  • Grammar & Spelling Check
  • Free Online Proofreading
  • Plagiarism Detection
  • No Downloads

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About Paper Rater is a free resource that utilizes Artificial Intelligence to help students write better. Our Paper Checker technology combines Natural Language Processing, Machine Learning, Information Retrieval, Computational Linguistics, and Data Mining to produce the most powerful automated proofreading tool available on the Internet today. is used by schools and universities in over 100 countries to help students improve their writing and check for plagiarism. It has been our mission to offer tools that are both powerful and accessible to users regardless of income.

As part of the development process, we put together a team of computational linguists and subject matter experts to develop a core Natural Language Processing (NLP) engine using statistical and rules-based NLP to extract language features from essays and robustly translate that into statistical models. The end product is a state-of-the-art system combining Automated Grammatical Error Detection, Automated Essay Scoring, Automated Proofreading, and plagiarism detection.

What makes us different?
We've tried out similar websites and found them to be out of touch with most writers' needs. We found false-positive rates as high as 50% on grammar detection. As the Hippocratic Oath encourages medical doctors to "first do no harm", we wanted to create tools that do not muddy the waters in the process of assisting with the craft of writing. These same websites require hefty payments for the use of their services, while our goal has always been to provide tools that are universally accessible. By 'accessible', we mean that our tools are free and not hidden behind signups, logins, and trial offers.

Plagiarism checker
In addition to our free online grammar check, we offer a free plagiarism detector that utilizes the massive indexes of the major search engines.


Vocabulary Builder
Besides our flagship product, we also offer a premiere Vocabulary Builder tool designed to help students learn proper usage of more sophisticated words. Learning a new word with just a definition was always a frustrating experience when growing up, so we solve this problem by integrating example sentences to show the correct usage of each word in a real context.

Social Responsibility

It's easy to provide lip service towards being a socially responsible business, but at PaperRater we want our actions to speak louder than our words. We strive to conduct business in a way that protects the environment, treats all humans with compassion, and helps those who are most in need. We hope that you do the same. Here are some of the causes that we currently support:
  • Poverty Reduction By partnering with the One Acre Fund, we provide training, seeds, and fertilizer to smallholder farmers, allowing them to increase their harvests and literally grow themselves and their communities out of poverty. We also provide scholarships to children in Guatemala allowing them to receive a good education.
  • Environmental Healing. We support conservation and reforestation initiatives. In September, we will be planting a forest with your help. More details coming soon...
  • Eradication of Slavery It's difficult to comprehend the acceptance of any form of slavery in the modern world. Help us eradicate sexual slavery and forced labor.
  • Clean Energy. All of our operations are powered by renewables (primarily wind and solar) so you can feel good when you submit a paper knowing that our servers are not contributing to pollution and greenhouse gases.
  • Microlending. Providing bags of rice harms local economies and creates dependency. Interest-free loans empower individuals in developing nations to build sustainable solutions to the problems that they face.
  • Medical Research. We support breakthrough research in cancer and aging.