FSI / FAR Calculator
What your plot may carry — and how much of it your building already uses.
Plot
Permissible FSI / FAR
Fill from Maharashtra’s UDCPR (Table 6-G)
Basic FSI, premium FSI and TDR for plots in non-congested areas, by the width of the road the plot faces, from the Unified Development Control and Promotion Regulations (not Greater Mumbai). UDCPR at the Directorate of Town Planning.
Footprint and floors
Your building optional
An existing building or a design: add its floors to see the FSI it uses and the area still left.
Built-up area by FSI component
| Component | FSI / FAR | Area | Area |
|---|
How it was worked out
For general information only, not legal advice. Templates are generic starting points — have a qualified lawyer review anything you rely on.
About the FSI / FAR Calculator
Find out how much floor area a plot may carry. Enter the plot area, the FSI (floor space index) or FAR (floor area ratio) that your development control regulations or zoning code allow — the base value plus any premium FSI you can buy, TDR (transferable development rights) you can load and ancillary FSI added as a percentage — and the ground coverage. The calculator gives the maximum built-up area, the largest footprint the building may cover, how many floors that makes and, for an existing or proposed building, the FSI it uses and the area still left to build.
The arithmetic is the same everywhere: the National Building Code of India defines FAR as the quotient obtained by dividing the total covered area (plinth area) on all floors by the area of the plot, and New York City’s Zoning Resolution calls floor area ratio the total floor area on a zoning lot, divided by the lot area of that zoning lot. Planners in other places say plot ratio. What changes from place to place are the limits, so every value here is yours to enter — or, for Maharashtra, filled from Table 6-G of the UDCPR.
How to use it
- Enter the plot area and its unit. If your regulations take land off before FSI is worked out — road widening, a reservation, an amenity space — enter it under Area deducted; tick Work premium FSI and TDR on the whole plot if your rules allow that for land you hand over.
- Choose whether your regulations write FSI as a ratio (1.5) or a percentage (150 %), then enter the base FSI and, if they apply, the premium FSI, the TDR you will load and the ancillary FSI percentage. In Maharashtra, open Fill from UDCPR Table 6-G, pick the road width and the authority, and the values are filled in.
- Add the ground coverage and a floor limit if your rules set them, and the area of a typical floor of your design if you know it. The floors are worked out with that floor plate, or else with the maximum footprint.
- To check a building, add its floors under Your building — each with its area and how many such floors — and read the FSI it uses and what is left.
- Copy the summary or download the figures as a CSV file; Reset brings back the example.
Examples
Plot 10,000 sq ft · base FAR 2.0 · lot coverage 50 %
Maximum floor area 20,000 sq ft · footprint 5,000 sq ft · 4 full floors
The first figure is the example the NYC Zoning Resolution gives under “floor area ratio”.
Base 1.10 · premium 0.50 · TDR 0.65 · ancillary 60 %
1.10 + 0.50 + 0.65 = 2.25 → 1,125 m²; ancillary 60 % of 2.25 = 1.35 → total FSI 3.60 → maximum 1,800 m²
Plot 1,000 m² · FSI 1.5 · ground coverage 40 % · at most 3 floors
Maximum 1,500 m² · footprint 400 m² · 3 full floors = 1,200 m²; 300 m² of the FSI stays unused under the floor limit
Plot 600 m² · FSI 1.5 · ground floor 280 m² + 2 floors of 290 m²
Built 860 m² of the 900 m² allowed: FSI used 1.43 (95.6 %), 40 m² left
Common uses
- Checking how much a plot can carry before buying it or agreeing a joint development.
- Planning floors and a footprint before the architect draws the first sketch.
- Seeing how much premium FSI or TDR is worth buying to add a floor.
- Finding how much area an existing building has left for an extension or another floor.
How the figures are worked out
- Plot area for the rules = plot area − area deducted (road widening, reservations, amenity space). Leave the deduction empty if your rules work on the whole plot.
- Total FSI = (base + premium + TDR) × (1 + ancillary % ÷ 100). With FSI written as a percentage, 150 % is the same as 1.5.
- Maximum built-up area = plot area for the rules × total FSI. With premium FSI and TDR on the whole plot, it is (plot area for the rules × base + whole plot × (premium + TDR)) × (1 + ancillary % ÷ 100), and the FSI shown is that area ÷ the plot area for the rules.
- Maximum footprint = plot area for the rules × ground coverage ÷ 100.
- Floors = maximum built-up area ÷ floor plate, where the floor plate is your typical floor or, without one, the maximum footprint. The whole number is the full floors; the rest is the area of one more, part floor. Floors count the ground floor (ground + 3 is 4 floors). A floor limit caps the floors, and the FSI above it stays unused.
- Your building: FSI used = its floor area ÷ plot area for the rules; remaining = maximum built-up area − its floor area.
FSI, FAR and plot ratio
They are one idea under three names: the floor area a building may have, as a multiple of its plot. FSI 1.5 on a 1,000 m² plot allows 1,500 m² of floor area — on 2 floors of 750 m², 3 of 500 m² or 6 of 250 m² — and ground coverage decides how large each floor can be. The National Building Code of India notes that in some state byelaws, the FAR (or FSI) has been expressed in the form of percentage, while the Code itself writes a ratio; the calculator takes either.
What counts as floor area differs between regulations: some leave out parking floors, staircases, lift wells, balconies or basements, or count them only in part. Enter the floor areas of your building the way your regulations measure them.
Maharashtra’s UDCPR preset
The Unified Development Control and Promotion Regulations for Maharashtra (UDCPR) apply across the state outside Greater Mumbai and a few special areas. Their Table 6-G (Regulation 6.3, plots in non-congested areas) gives a basic FSI of 1.10 on every plot, and premium FSI and TDR loading by the width of the road the plot faces: for municipal corporations (and CIDCO as planning authority for NTDA) from nothing below 9 m up to premium 0.50 and TDR 1.40 on roads of 30 m and more, a maximum building potential of 3.00; for the remaining authorities and areas up to premium 0.30 and TDR 1.10, a maximum of 2.50. Note (i) to the table adds ancillary area FSI of up to 60 % of the proposed FSI (up to 80 % for non-residential use), on payment of premium.
Under UDCPR, FSI is worked on the net plot area (definition 63; Regulation 3.9 takes off the amenity space and the development plan’s roads and road widening), so enter those areas under Area deducted. Where the reservation or amenity space is handed over to the authority, note (xiv) lets the potential in premium FSI and TDR be worked on the whole plot and only the basic FSI on the net plot: tick Work premium FSI and TDR on the whole plot. Congested areas follow a different table (6-A), Chapter 10 adds rules of its own for some cities (Pune, Thane, Nagpur, Navi Mumbai and others), special schemes have their own, and where there is no planning authority the TDR column does not apply. The preset fills the fields; check them against the current regulations before relying on them.
Sources
- National Building Code of India (SP 7), Bureau of Indian Standards — definition of floor area ratio; transferable development rights as compensation in the form of floor area ratio (FAR) or development right.
- NYC Zoning Resolution, Section 12-10 (definitions) — floor area ratio and lot coverage.
- UDCPR for Maharashtra, Directorate of Town Planning — Acts and Rules — definition 63 (FSI on the net plot area), Regulation 3.9 (net plot area) and Regulation 6.3, Table 6-G with its notes (i) ancillary FSI and (xiv) premium FSI and TDR on the whole plot.
Limitations
- Every limit is the one you enter: FSI, coverage and floor limits change with the city, zone, road width, use and plot size, and the regulations that apply decide — check them with the planning authority.
- Setbacks (marginal distances), height limits, parking, fire and open-space rules also limit what can be built; the calculator checks none of them except the floor limit you enter.
- Regulations differ on what counts as floor area and on whether FSI is worked on the gross or the net plot; enter areas the way yours measure them.
- This is an estimate, not legal advice or a building approval: only the authority’s sanctioned plan says what you may build. Have an architect or licensed engineer check the plan.
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
What is FSI or FAR?
The floor area a building may have as a multiple of its plot area: total floor area of all floors ÷ plot area. FSI 2 on a 500 m² plot allows 1,000 m² of floor area in all, spread over as many floors as the coverage and height rules allow.
How do I calculate the maximum built-up area of my plot?
Multiply the plot area (after any deductions your rules make) by the total permissible FSI: base FSI, plus premium FSI and TDR if you use them, plus any ancillary FSI. A 500 m² plot at 1.10 + 0.50 + 0.65 = 2.25 may have 1,125 m²; with 60 % ancillary FSI, 1,800 m².
What is the difference between FSI and ground coverage?
FSI limits the floor area of all floors together; ground coverage limits how much of the plot the building may cover. With FSI 1.5 and 50 % coverage on 600 m², you may build 900 m² in all on a footprint of at most 300 m² — 3 floors of 300 m², or more, smaller floors.
What are premium FSI and TDR?
Premium FSI is extra FSI the authority grants on payment of a premium. TDR (transferable development rights) is development right in the form of floor area, given as compensation for land surrendered elsewhere — for a road widening, for example — and bought and loaded onto another plot. Both add to the base FSI up to the limits your regulations set.
Is FSI worked out on the gross or the net plot area?
It depends on the regulations. The National Building Code divides by the plot area; Maharashtra’s UDCPR divides by the net plot area, but where the land is handed over it lets premium FSI and TDR be worked on the whole plot (Table 6-G, note xiv). If yours use the net area, enter what is deducted (road widening, reservations, amenity space) and the calculator works on the rest; tick the whole-plot box when your rules allow it.
How many floors can I build?
Divide the maximum built-up area by the area of one floor. 1,500 m² on floors of 400 m² is 3 full floors and 300 m² on a fourth. Height limits, setbacks and the floor limit of your zone can stop you earlier — then part of the FSI stays unused.
My rules say FSI 150 % — is that the same as 1.5?
Yes. Some regulations write FSI or FAR as a percentage of the plot area, others as a ratio. Choose Percent or Ratio above the FSI fields and type it the way your regulations do.