See how much of a home's gross building area is shared space. Enter the gross building area and the net internal area, and the tool returns the shared area, the shared-area ratio, the shared-area coefficient and the usable-area ratio. These results are approximations for general information only, not a survey or a quote, and definitions of shared area and usable-area ratio vary, so check the floor plan and the sale documents before relying on them.
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How to Use the Shared Area Ratio Calculator
Enter the gross building area and the net internal area, then press Calculate to see the shared area and the ratios that describe it.
What the numbers mean
Shared area is the gross area minus the net internal area.
Shared-area ratio is the shared area divided by the gross area.
Usable-area ratio (the "delivery rate") is the net area divided by the gross area, so the two ratios add up to 100%.
Shared-area coefficient is the shared area divided by the net area, used in some markets instead of the ratio.
Tips
A higher usable-area ratio means more of what you pay for is space you can use. Compare the ratio, not just the headline size, when you look at two homes with the same gross area.
Features
Shared area, shared-area ratio and usable-area ratio in one view
Both the ratio over gross and the coefficient over net
Net input can never exceed the gross area
Copy the result to your notes
All processing runs locally in your browser. Your data is not uploaded to any server.
These results are approximations for general information only and are not a survey or a quote. Definitions vary, so check the floor plan and the sale documents.