My friend Dr. Sean McDowell has provided an informative post at his website with the latest, most researched update available on how many New Testament manuscripts we have available:
Since we do not have the original New Testament writings (the autographa), textual critics aim to determine the reliability of existing copies. For any particular work or collection of works, the greater the number and the earlier the dating of the manuscripts, the easier it is to reconstruct a text closer to the original and identify errors or discrepancies.
Greek Manuscript total: 5,856
*Earliest manuscript: AD 130 (John Rylands Papyrus: P52)
Non-Greek Manuscripts (Armenian, Latin, etc.): 18,130+
Total Manuscripts: 23,986
How do the New Testament documents compare with other ancient books? A stack of existing manuscripts from the average classical writer would measure about four feet high. Yet the New Testament manuscripts would stack to more than one-mile high.