The quick tool adds measured room rectangles in feet and shows their usable-area sum. It does not calculate statutory RERA carpet area: internal partition areas and the legal exclusions need the separate checks below.
Do not use the result as a legal certificate, property survey or substitute for the project’s registered disclosure and sanctioned plans. An interior site measurement may use a different boundary from RERA carpet area. Confirm which figure a quotation, drawing or property comparison uses.
How to use the add up home rooms
Add measured rooms one at a time. This usable-area sum excludes internal partitions and is not a certified RERA carpet area. Use the short form above for the initial measurement. Check your quotation PDF. Confirm the measurement basis and included work with the vendor before comparing prices.
What is carpet area under RERA?
Section 2(k) of the Real Estate (Regulation and Development) Act, 2016 defines carpet area as an apartment’s net usable floor area. It excludes the area covered by external walls, service shafts, an exclusive balcony or verandah and an exclusive open terrace. It includes the area covered by internal partition walls.
That last distinction matters. Clear floor measurements taken between finished wall faces do not automatically include the plan area beneath internal partitions. Adding only room floor areas can therefore produce a useful interior floor quantity but an incomplete RERA carpet-area calculation.
| Component | Treatment in this calculator | Evidence to use |
|---|---|---|
| Net usable room floors | Included | Dimensioned plan or checked room schedule |
| Internal passages, stores and usable enclosed areas | Included | Same measurement boundary as the room schedule |
| Internal partition-wall plan area | Included separately | Declared area or measured plan geometry |
| External-wall area | Excluded | Sanctioned or dimensioned wall plan |
| Service shafts | Excluded | Labelled plan and project disclosure |
| Exclusive balcony or verandah | Excluded | Separate declared or measured area |
| Exclusive open terrace | Excluded | Separate declared or measured area |
How is carpet area calculated?
Add the measured net usable floor areas inside the apartment. Then add the plan area covered by internal partition walls. Keep statutory exclusions outside the carpet-area total.
Carpet area = net usable floor area + internal partition-wall area
Use the single room area calculator for inside length multiplied by width. Wall area needs a separate height measurement.
The calculator also totals the excluded inputs. That separate total is an audit aid, not a built-up-area definition. “Built-up area” and “super built-up area” are used with varying boundaries in market documents, so the tool does not label the combined figure as either one.
How to use the add up home rooms
Add measured rooms one at a time. This usable-area sum excludes internal partitions and is not a certified RERA carpet area. Use the short form above for the initial measurement. Check your quotation PDF. Confirm the measurement basis and included work with the vendor before comparing prices.
Worked carpet-area example
Assume a plan shows 820 square feet of net usable floors across the living room, bedrooms, kitchen, bathrooms, passages and store. It separately shows 55 square feet under internal partition walls. The calculated carpet area is 875 square feet, or about 81.29 square metres.
The same record identifies 72 square feet of external walls, 18 square feet of shafts and 65 square feet of exclusive balcony. Those 155 square feet remain excluded. The tool reports a total recorded footprint of 1,030 square feet only to reconcile the entered components. It does not call that figure built-up, super built-up or saleable area.
If the plan does not identify the internal partition-wall area, record that gap. Do not enter zero merely to obtain a smaller finished result. The result can still help organize the usable-room schedule, but it is not a complete RERA carpet-area calculation until the included wall component is established.
How should a homebuyer verify carpet area?
Start with the project’s registration record and agreement documents. Match the apartment identifier, wing or building, floor, configuration, plan revision, unit and carpet-area figure. Obtain the dimensioned plan that supports the disclosure.
Then reconcile the plan components. Check whether an exclusive balcony, verandah or open terrace is stated separately. Identify service shafts and the apartment’s external boundary. Confirm that internal partition walls are included rather than deducted with external walls.
A physical survey answers a different question: what exists on site now. Alterations, finishes, columns, ducts and measurement points may make a clear floor reading differ from a plan figure. For a purchase, dispute or formal certification, use the responsible registered professional and legal documents. Interio does not certify either.
Keep the original square-metre disclosure when one is available. If you also need square feet for interior planning, store both values and the conversion used. Rounding several rooms separately can create a different total from converting the final combined area, so retain the unrounded source figures in the calculation record.
When comparing two flats, use the same definition and evidence level for both. A registered figure for one home and a broker’s estimated ratio for another are not comparable measurements. Mark missing figures as unknown instead of silently filling them with an average.
| Verification step | Question to answer | Record to retain |
|---|---|---|
| Identify the apartment | Is this the correct unit and plan revision? | Registration entry and plan reference |
| Confirm the unit | Are all areas in square metres or square feet consistently? | Original value and any conversion |
| Trace inclusions | Are usable floors and internal partitions accounted for? | Marked component schedule |
| Trace exclusions | Are external walls, shafts, balcony/verandah and open terrace separate? | Marked plan and disclosure |
| Compare the site | Does the built apartment match the relevant plan? | Dated checked survey |
| Resolve a mismatch | Who is qualified to explain and certify the difference? | Written professional response |
Carpet area versus interior floor area
Interior projects often need clear finished floor area, wall area, ceiling area and product order quantity. These are not synonyms for RERA carpet area. A flooring contractor may measure the finishable floor between wall faces. A painter needs wall and ceiling surfaces. A property record includes internal partition-wall area under the statutory carpet definition.
This separation also prevents budget errors. A carpenter may price a cabinet by elevation or running length. A false-ceiling installer may measure only approved ceiling faces. A designer may use clear room dimensions to test furniture. None of those quantities should be replaced with the flat’s carpet area merely because every figure is shown in square feet.
| Project decision | Quantity it needs | Why carpet area is insufficient |
|---|---|---|
| Compare registered apartments | Declared RERA carpet area under one definition | This is the carpet-area job |
| Order flooring | Measured finishable floor plus product-specific allowance | Internal wall area is not tiled floor |
| Price painting | Measured wall and ceiling faces under the quotation rule | A plan area does not show surface height or openings |
| Test furniture layout | Clear room dimensions, doors, windows and circulation | Equal areas can have different shapes |
| Price fitted joinery | Item dimensions and the bidder’s stated unit | Cabinets are not priced from whole-flat area alone |
Use the Mumbai cost guide to define the complete budget. Check actual offers with the PDF quote checker.
Carpet area questions
Does RERA carpet area include internal walls?
It includes the area covered by internal partition walls. It excludes the area covered by external walls. Use plan footprint area, not the vertical face area of a wall.
Is a balcony included in carpet area?
An exclusive balcony or verandah is excluded under section 2(k), as is an exclusive open terrace. Keep each separately identified in a comparison.
Can carpet area be calculated from super built-up area?
Not exactly from that figure alone. Common-area loading and component boundaries vary. A percentage can only be an explicitly labelled assumption, so this calculator does not offer one.
Is carpet area the same as the area where carpet can be laid?
No. The everyday phrase suggests clear usable floor, but the statutory definition also includes the area covered by internal partition walls. Use the legal definition when comparing a RERA disclosure.
Can I use room measurements for the calculation?
Yes, for the net usable floor component, if every relevant enclosed usable space is measured under one boundary. You still need the internal partition-wall area and must keep statutory exclusions separate.
Is this a RERA certificate?
No. It is deterministic arithmetic based on the values you enter. It does not verify a project record, sanctioned plan, site condition, title document or legal classification.