EFL students tend to have a common problem of insufficient vocabulary. Some studies argued that English vocabulary was one of the most difficult areas in terms of learning English. The participants (N=1938) were asked to take the English vocabulary tests in spelling, reading, and listening. After the tests, vocabulary Quotient (VQ) was used to estimate the actual size of English vocabulary of the participants. The findings of this study were generalized as the following: (1) the growing rate of English vocabulary in spelling was about 1197 words per year, the growing rate of English vocabulary in reading was about 1443 words per year, and the growing rate of English vocabulary in listening was about 1402 words per year, (2) the growth of vocabulary size in spelling was the least, and (3) the growth of vocabulary size in reading was the greatest. Results of this study suggested that English learners did not tend to equally develop their vocabulary sizes in the areas of spelling, reading, and listening.