Kukri before WWI often had blade lengths around 15", but ther were quite a few that were not that size as well, anything from 122 upwards, epending on the regiment and were in India or Nepal they were made.
WWI kukri have blade lengths from 12-14" in length and there are endless variations, as there is in all periods up to the end of WWII.
WWII blades generally start from 12" and go up to 13.5" blade lengths, one of the most used tyes was a horn handled 12.5" blade, also the M43, which has a blade variation length of 13"-13.25" as a general rule.
WWII handle lengths did vary as quite a few were also made for British as opposed to Gurkha troops, especially the Chindits.
By the Borneo conflict, the kukri had for most of the time a blade length of 11" and a 5" horn handle. Occasionally there there was isued a 10.25-10.5" version, and there was an 11.5" version.
Today however, the only issued kukri by the MOD in the UK is the 11" blade 5" horn handle type, the 10.25-10.5" Kukri blade is no longer issued, and hasnt been for some time now.
I hope that has clarrified blade sizes Tora