Measure your plot
FSI compares all proposed floor area with plot area. Coverage compares the ground footprint with plot area.
Property/Finance · FREE
Floor Space Index
Measure proposed FSI and ground coverage without mistaking the result for building permission.
Your planning summary
Complete the inputs to see your result and assumptions. No login or contact details required.
UNDERSTAND YOUR RESULT
Understand Your Plot and Floor Area
Compare your proposed total floor area with your plot size. FSI and ground coverage describe different parts of a plan; neither grants permission.
Add proposed floors
Permitted FSI depends on the applicable authority, road and site rules. The calculated ratio does not establish legal eligibility.
Review ratio and coverage
Review the displayed breakdown and assumptions before using this estimate.
Explore an illustrative example
30 × 50 ft plot. Use the example button in the calculator to apply these editable inputs.
Illustrative measurements or assumptions only; not an approved design, quote or offer.
What changes your result?
- FSI and coverage answer different questions. FSI compares all proposed floor area with plot area. Coverage compares the ground footprint with plot area.
- A ratio is not permission. Permitted FSI depends on the applicable authority, road and site rules. The calculated ratio does not establish legal eligibility.
Assumptions and limits
Confirm measurements, inclusions and price assumptions. These planning results do not replace professional engineering, legal or lender advice.
Results retain the assumptions you selected. Compare like-for-like areas and avoid counting the same item twice.
View Technical Calculation Details
FSI = total proposed floor area / plot area. In uniform mode total area = entered area per floor × floors. Ground coverage = footprint / plot × 100; permitted FSI remains a separate authority decision.
Currency totals: 2 decimal places; geometry and quantities: 6. Whole units/boxes round upward with floating-point ULP correction; internal calculation precision is retained.
Formula 2.0.0 · Content/schema 2
Sources and review information
References last checked 2026-10-29. This is not certification of a fee schedule or property.
Your questions, answered
FSI and coverage answer different questions
FSI compares all proposed floor area with plot area. Coverage compares the ground footprint with plot area.
A ratio is not permission
Permitted FSI depends on the applicable authority, road and site rules. The calculated ratio does not establish legal eligibility.
Can I save or download for free?
Yes. PDF and comparisons are free. Saving a report is optional and needs consent; a calculation needs no contact details.
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