Square footage - Is there a standard?

Looking at a few properties for sale in Dublin recently, each EA seems to have a different way of calculating square footage. Is there a standard?

For example;

One Percy Lane is being marketed as 174 msq - myhome.ie/residential/brochu … ge/3070470

However, at the architect drawings for the development - dublincity.ie/AnitePublicDocs/00415768.pdf - show only 152 sqm of internal space,

Taking away the 12 msq garage, there would only be 140 sqm of internal living space - 0nly 80% of the advertised 174

I believe the standard is ‘Get your own surveyor to check the measurements’.