Measurements inside or outside

[simonmac]

Hi folks,
Could anyone tell me if i were to get a build price for four flats would the m2 be calculated on the internal or external measurements?
Thank you in advance Simon

[dan.b]

There's internal 'floor area', which is uses interior dimensions and includes multiple stories (so a simple construction can take one floor area and simply multiply it by the number of stories).
Then there's the building footprint, which use the external dimensions.

Depends what you need.