Back to Homepage
Floor Area & IPMS Calculator
Add rooms as length x width, mark deductions, and total them on a GIA, GEA, NIA or IPMS basis — to the RICS Code of Measuring Practice.
GIA / GEA / NIAIPMSRICS measurementPDF scheduleFree to use
Gross Internal Area — Area within the internal face of the external walls, measured at each floor. Includes internal walls, columns, stairwells and lift wells. Excludes external open balconies and the wall thickness itself.
Rooms & spaces
Room / spaceL (m)W (m)AreaDeduct
17.10
9.28
2.00
Area within the internal face of the external walls, measured at each floor. Includes internal walls, columns, stairwells and lift wells. Excludes external open balconies and the wall thickness itself.
Gross Internal Area (GIA)
28.38 m²
305.5 ft²
Gross
28.38 m²
Deductions
0.00 m²
Measurement bases
GIA — Gross Internal Area
Area within the internal face of the external walls, measured at each floor. Includes internal walls, columns, stairwells and lift wells. Excludes external open balconies and the wall thickness itself.
GEA — Gross External Area
Area measured to the external face of the external walls. Used for planning, council tax banding and some cost estimates.
NIA — Net Internal Area
Usable area within the internal finishes. Deduct stairwells, lift wells, WCs, plant rooms, common entrance halls, internal structural walls and columns. Used for office and retail lettings.
IPMS — International Property Measurement Standards
Globally consistent basis. Record components separately (internal walls, balconies, etc.) so the area can be reported as IPMS 1/2/3. Preferred for cross-border and institutional work, including Singapore (alongside URA Gross Floor Area and strata area), the Gulf, Australia and North America.
Using this correctly
Frequently Asked Questions
Disclaimer: This calculator totals room areas you enter and applies deductions you flag. It is a calculation aid, not a measured survey or valuation. For formal work follow the current RICS Code of Measuring Practice / RICS Property Measurement (IPMS), state the basis and any assumptions, and verify all dimensions on site.
