Default wordpress excerpt length is 55 words. It’s easy to change the default excerpt length in wordpress in less than 2 minutes to desired length. I made changes to wordpress 2.9.2 code.

1. Login into Directory where wordpress is installed
2. Open the file Directory > wp-includes > formatting,php
3. Search for 55 or $excerpt_length = apply_filters(‘excerpt_length’, 55);
4. Change the value 55 to desired number of words and save the file.
5. Refresh the page and see the results ( you may have to clear the cache)