To reset your Kindle reading time, fire up your Kindle and open a book. Head to the search box, which you would normally use to search for words or phrases in the book, and type the following case sensitive command:
Your Kindle will perform a search but won’t find anything. Press the Back button to head back to your book and you’ll now notice in the lower left corner that your reading time statistics have been reset and that the Kindle is now “(re)learning reading speed.” After a few pages of a normal reading, the stats will update with new estimated times based on your current pace.
While this is helpful for getting rid of those anomalous incidents where you left the Kindle open for a long time without turning any pages, it can also be useful if you’re loaning your Kindle to a friend or family member. By resetting the reading statistics, you’ll give the other reader more accurate data for their own usage.
Thought this may help someone as mine was constantly saying '1 minute until end of chapter' when I was at the start of one :)