Informal phonics quizzes are not so much a test of ability but a developmental tool. Free printouts on the Internet offer multiple choice sheets with pictures that help children match simple sounds with letters and objects.
Once letters are matched with basic letters, word decoding is the next step. Children learn to decode long and unfamiliar words by breaking the words into small pieces and sounding out each part. Simply reading a book together is a good test of a child's ability to decode words.
The Internet offers a variety of printable tests regarding word recognition. There is a certain vocabulary level 6-year-old students are expected to have achieved to meet the accepted reading level.
There are free tests available online designed to determine if 6-year-old students are meeting the acceptable standards for their grade level. The free printable tests at the Child Development Institute will enable you to determine the current academic reading level of your 6-year-old child based on simple tests and an online evaluation process.