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Built-Up Area

General

Built-Up Area

Carpet area plus the wall thickness of a flat, typically 10-15% more than carpet area, but still excluding shared common areas counted in super built-up area.

Definition

Built-up area is a flat's carpet area plus the thickness of its internal and external walls, capturing the full physical footprint of the unit rather than just the open, usable floor space. It typically runs 10-15% larger than carpet area, reflecting the real but non-usable space walls occupy within the flat's boundaries.

Built-up area sits between carpet area and super built-up area in the hierarchy of space measurements. Unlike super built-up area, it doesn't include any proportional share of common building spaces like lobbies, staircases, or corridors, those additions only enter the picture at the super built-up level.

Formula

Built-Up Area = Carpet Area + Wall Thickness (internal and external walls within the unit)

Worked Example

A flat has a carpet area of 800 sq ft, with wall thickness adding approximately 12% to the total.

  • Built-up area: 800 × 1.12 = 896 sq ft

If this same flat is marketed with a super built-up area of 1,050 sq ft (adding a proportional share of common areas on top of built-up area), the buyer is paying for roughly 1,050 sq ft while actually getting only 800 sq ft of genuinely usable carpet area, a meaningful gap worth understanding before comparing price per square foot across properties.

Key Things to Know

  • Sits between carpet area and super built-up area in the measurement hierarchy. Carpet area is smallest and most accurate for usable space, built-up area adds walls, super built-up area adds common areas on top of that.
  • Typically 10-15% larger than carpet area. This percentage reflects the flat's own wall thickness, not shared building spaces, which come later in the super built-up figure.
  • Doesn't include any share of common areas. This is the key distinction from super built-up area, built-up area is still contained entirely within the unit's own physical boundaries.
  • Not the primary RERA-mandated disclosure figure. Carpet area carries that specific regulatory requirement, built-up area is often provided as useful supplementary context rather than the mandated headline number.
  • Useful as a middle-ground reference point, but carpet area remains the most reliable basis for comparison. When evaluating true value, always anchor comparisons to carpet area rather than built-up or super built-up figures.

Related Terms

Carpet AreaCarpet Area

Frequently Asked Questions

Is built-up area the figure I should use to compare flat prices?
It's better than super built-up area for comparison, but [carpet area](/glossary/carpet-area/) is still the most accurate basis, since built-up area includes wall thickness that isn't actually usable floor space, even though it's closer to the real figure than super built-up area.
Why does built-up area include wall thickness at all?
Because walls are a real, unavoidable part of a flat's physical footprint, built-up area accounts for the full structural area within the unit's boundaries, not just the open, walkable floor space that carpet area captures.
How much bigger is built-up area compared to carpet area typically?
Commonly 10-15% larger, reflecting the wall thickness within the flat, thicker walls, common in older or higher-quality construction, can push this percentage somewhat higher.
Does built-up area include a share of common building areas?
No, that's specifically what distinguishes it from super built-up area, which does add a proportional share of lobbies, staircases, and other shared spaces on top of built-up area.
Is built-up area a legally mandated disclosure like carpet area?
RERA specifically mandates carpet area disclosure, built-up area is often provided as supplementary information but doesn't carry the same regulatory disclosure requirement as carpet area does.