Opinions are divided over how much it will cost businesses worldwide to prepare their computer systems for the year 2000. Most observers are happy simply to say "nobody knows". The most commonly-quoted figure was calculated by the independent market analysts, the US-based Gartner Group, who reckon that the cost to industry and governments across the globe will be between US $300bn and US $600bn - the GDP of a decent-sized developed country.

UK observers are happier to stick to micro-economic costings, with the consensus being that the likely cost of having programs checked for date compatibility will begin at about 80 pence per line of computer code. However, this expenditure - which would automatically amount to millions for some companies - will cover only the checking of the programs. Actually changing them where necessary, and then re-testing them, will cost extra. Industry estimates suggest the cost to a medium-sized company of checking and amending all its systems may be pounds 50m to pounds 70m.