These are the 300 most frequently used characters in modern Chinese. Together, they account for approximately 65% of the characters typically encountered in a modern Chinese newspaper.
These characters make up the Class I character set in the flashcards tool available on this website and as part of the Clavis Sinica software. To find out how many of them you already know, take the Chinese Character Test at the Beginner level and note your score at the end.
If you don't recognize most of these characters, you can learn them in a systematic way using the Stepping Stones lesson series provided on this site. You can also drill yourself on these characters using our Chinese Flashcards app for iPhone.
For a list of the next 500 most commonly used characters, see the Chinese Text Sampler website.