Globally there are now approximately 17,300 nuclear warheads.
(Upated as of early 2013)
United States 7,700
United Kingdom 225
North Korea <10
Estimated Total: 17,300
This total is from the Federation of American Scientists source:
(FAS data is from the Nuclear Notebook in the Bulletin of the Atomic Scientists,
and the nuclear appendix in the SIPRI Yearbook.)
This is a decrease from the global high of 70,000 nuclear warheads in 1986.
For updates or comparisons, go to:
• The Bulletin of the Atomic Scientists
• Center for Defense Information (Washington)
(Note that where there are discrepancies about numbers, you may wish to check the above sources and compare.)
To view the world Proliferation Status and Warheads (2007) map (a list of countries Possessing Ballistic Missiles, and how many) go to The Carnegie Endowment for International Peace site here
For a graphic idea of the number of nuclear weapons currently in the US arsenal, have a look at the "ball bearing demonstration": http://truemajority.org/fun/