RERA CARPET AREA vs MOFA CARPET AREA

MOFA Carpet Area
EXCLUDES all (1) internal walls, (2) all external walls, (3) all balconies, (4) dry spaces, (5) flower beds (6) all common areas.

Basically, MOFA CARPET AREA is the layout inside your house, the exact square feet that carpet would be required. 

RERA Carpet Area
EXCLUDES all (1) all external walls, (2) all balconies, (3) dry spaces, (4) flower beds (5) all common areas.

RERA CARPET AREA is MOFA Carpet Area + Area used by internal walls 

Hence the difference between the MOFA carpet area and the RERA carpet area is the thickness of the internal walls.

This will not seem more to you, but in a typical apartment where the e normal carpet area is 800 sq ft, the RERA carpet area can be 5% or 10% more than 850 sq. ft. to 880 sq. ft. depending on the number of internal walls and thickness of internal walls.

Hence, MOFA Carpet Area was the actual carpet area; however, builders would only use BUILT-UP Area or SUPER BUILT-UP Area while selling or booking or during the launch.

Hence in order to have uniformity amongst builders RERA Carpet Area was introduced where the builder adds the (area sq. ft of the internal wall) to the MOFA carpet area while quoting the Current RERA CARPET AREA.

NEXT TIME YOU BUY A HOUSE consider 5% to 10% lesser actual carpet area given on the RERA CARPET AREA.

...... you may also be interested in reading about the differences between the RERA carpet area v/s USABLE carpet area.