If you look at the chart above (click to enlarge) you can see that the number of unallocated /8s has now halved since the start of the year. In 2010, we have been allocating IPv4 address space at a rate of more than one /8 per month.
So does this mean that the last /8 will be allocated in about another 10 months time? Probably not. It is hard to predict the exact rate at which addresses will be allocated. We know that the last five /8s will all be allocated on a single day. This is because the Global Policy for the Allocation of the Remaining IPv4 Address Space requires us to allocate one /8 to each RIR when the pool falls to five /8s. An RIR will request additional IPv4 addresses, be allocated one or more /8s and that event will trigger the last allocation of IPv4 space from IANA to the RIRs.
For the last few years, Geoff Huston has been using mathematical modelling to project the changing set of dates for when the IANA pool of unallocated /8s will be empty and when the RIRs’ own pools will follow. At the moment his site predicts June 2011 for the IANA pool with the RIRs following about six months later. Of course, his site models future trends based on historical behaviour and people might well act differently in the future than they have in the past, so we might see something different but at this point we are looking at fine detail rather than significant extensions.
So we can’t give you a precise date for when the final allocations will be made but we can say “not long now!”