Onex: observed built density
Municipality in the canton of Geneva · FSO no. 6631 · Parcel data as of July 2025
- Parcels
- 1’596
2 % of the canton
- Municipal zones
- 8
- Median utilization
- 79 %
Canton: 49 %
Switzerland: 10 %
- Median GFZ
- 0.32
Canton: 0.23
Switzerland: 0.09
- Median height
- 8.7 m
Canton: 9.3 m
Switzerland: 9.5 m
- Median floors
- 2.3
Canton: 2.4
Switzerland: 2.3
About Onex
Onex is a municipality in the canton of Geneva. The parcel data lists 1’596 parcels in 8 municipal zone types. The zone types with the most parcels are Zone de développement 5 (922), Zone de développement 3 (426) and Zone de développement 4B protégée (180).
The median parcel is built to a volume utilization of 79 %; half of the parcels lie between 17 % and 145 %. The canton median is 49 %, so Onex sits above it.
The median building height is 8.7 m at 2.3 floors, and the median floor-area ratio (GFZ) is 0.32. Parcels built in the last 20 years reach a mean volume utilization of 125 % (234 parcels), lower than the 143 % across all building years.
Parcels by municipal zone
| Zone | Parcels | Median utilization |
|---|---|---|
| Zone de développement 5 | 922 | 79 % |
| Zone de développement 3 | 426 | 95 % |
| Zone de développement 4B protégée | 180 | 92 % |
| Zone agricole | 26 | 0 % |
| Zone des bois et forêts | 22 | 0 % |
| Zone de verdure | 15 | 0 % |
| Zone des eaux et des rives | 3 | 0 % |
| Zone sportive | 2 | 50 % |
Volume utilization (ratioV)
Of the 1’582 parcels with a value, half lie between 17 % and 145 %. The median is 79 % and the mean 137 %.
Share of parcels by range
- below 50 %33 %
- 50 % to below 100 %29 %
- 100 % to below 150 %13 %
- 150 % and above24 %
Floor-area ratio (GFZ)
Of the 1’582 parcels with a value, half lie between 0.10 and 0.77. The median is 0.32 and the mean 1.02.
Share of parcels by range
- below 0.5067 %
- 0.50 to below 1.0014 %
- 1.00 to below 1.503 %
- 1.50 and above17 %
Building height
Of the 1’202 parcels with a value, half lie between 7.1 m and 11.6 m. The median is 8.7 m and the mean 11.3 m.
Share of parcels by range
- below 8 m39 %
- 8 m to below 12 m38 %
- 12 m to below 20 m12 %
- 20 m and above11 %
Number of floors
Of the 982 parcels with a value, half lie between 1.7 and 3.2. The median is 2.3 and the mean 3.0.
Share of parcels by range
- below 219 %
- 2 to below 340 %
- 3 to below 530 %
- 5 and above12 %
Building age cohorts
Mean volume utilization of the parcels built inside each window, from all years on record down to the last five. The windows overlap: the last 20 years include the last 5.
| Built in | Parcels | Mean utilization |
|---|---|---|
| All years | 1’596 | 143 % |
| Last 60 years | 822 | 133 % |
| Last 40 years | 542 | 116 % |
| Last 20 years | 234 | 125 % |
| Last 15 years | 180 | 134 % |
| Last 10 years | 119 | 131 % |
| Last 5 years | 54 | 142 % |
How to read this page
room shows observed built density: what has been built on the parcels, not what the zoning permits. Volume utilization (ratioV) compares the built volume of a parcel with the reference volume of its municipal zone type. The floor-area ratio (GFZ) is floor area divided by parcel area; building height and number of floors are taken from the buildings on a parcel. Figures pool all municipal zones of the area. Medians and quartiles are read from bins 10 points (ratioV), 0.1 (GFZ), 2 m (height) and 1 floor wide, so they are exact to within one bin; means are exact. A parcel counts in a distribution only when the parcel data has a value for it. The floors distribution leaves out parcels without a building (0 floors).