Plot ratio tells you how much floor space may be built on a site compared with the size of the land, and gross floor area is the floor space that results. Multiply the site area by the plot ratio and you have the gross floor area the plan allows. Together they are the quickest way to judge how intensely a site will be used, which in turn shapes building height, the number of units and how much open space residents or occupiers will share.
The basic sum
The formula is simple: gross floor area equals site area multiplied by plot ratio.
Two projects in this guide publish all three figures, so you can see it in action:
- Dorset Gardens sits on 10,399.0 sq m of land at a gross plot ratio of 3.5, giving a maximum permissible gross floor area of about 36,397 sq m for 425 planned homes.
- The Serra Residences pairs a 4,774.80 sq m site with a ratio of 2.8, so 13,369.44 sq m may be built before bonus space is added, for 133 homes.
The same arithmetic applies to industrial land. Generations @ Tannery, a B1 industrial project, plans about 16,190 sq m of gross floor area on a 3,150.10 sq m site, a plot ratio of roughly 5.13.
Where the plot ratio comes from
URA's Master Plan assigns every plot a land use, such as residential, commercial or business, and a maximum gross plot ratio. For land sold by the state, the tender documents fix the ratio and the maximum floor area. For privately owned land, the developer works to the Master Plan figure unless it applies for a change, which may involve a differential premium.
Height controls, setbacks from the boundary and other planning rules apply on top. Two sites with the same plot ratio may therefore end up with quite different buildings, one a cluster of mid-rise blocks and the other a single tower with a large garden.
What counts as gross floor area
Gross floor area generally includes the enclosed floor space of every storey, measured to the outside of the walls. Certain spaces are excluded or granted as bonus floor area under URA's guidelines: some balconies, sky terraces, communal facilities and green features, within limits. This is why a project's built floor area can be somewhat higher than the base figure from the plot ratio.
When a fact sheet says "excluding bonuses", as The Serra Residences' does, it is giving the base allowance before those additions.
Reading density
Plot ratio is a measure of density, and density affects daily life in a few ways:
- **Height and form.** On a given site, a higher ratio usually means taller blocks or more of them.
- **Open space.** A lower ratio can leave more ground for landscaping and facilities, though design choices matter as much as the number.
- **Number of neighbours.** More floor area usually means more units sharing the same facilities, lifts and car park. Large estates spread the cost of facilities across more owners, which can keep maintenance contributions moderate; smaller ones offer a quieter, more exclusive feel.
- **Traffic and amenity load.** A dense site near a station or town centre makes sense; the same density on a quiet lane brings more cars onto narrow roads.
Neither high nor low density is better in itself. A city-fringe tower at a high ratio near an MRT interchange and a low-rise suburban estate at a modest ratio serve different buyers.
What the numbers do not tell you
Plot ratio and floor area say nothing about unit sizes, layouts, facing, ceiling heights or the quality of the design. Two developments with the same floor area might hold very different mixes: many compact apartments in one, fewer large family units in the other. Divide the floor area by the number of homes and you get an average size, which is a rough guide at best.
For industrial and commercial space, plot ratio sits beside more specific measures: floor loading, ceiling height, ramp or cargo-lift access and power supply. The industrial guide covers those.
Plot ratio and future change nearby
Because the Master Plan sets a ratio for every plot, it also hints at what could rise around a home later. A row of two-storey shophouses on land zoned for a higher ratio may be redeveloped one day into something much taller, while a park or a school site is likely to stay open.
URA reviews the Master Plan periodically, and ratios can be raised in growth areas such as town centres and around new rail stations. Neighbouring estates sometimes sell collectively when the allowed floor area on their land grows well beyond what stands there today. For a buyer, checking the zoning and ratio of the plots next door is a quick way to judge whether the view and the surroundings are likely to stay as they are.
Using these figures when comparing projects
Look for site area, plot ratio and the number of units on each profile in this directory, and on the developer's own fact sheet. A few comparisons are worth making:
1. **Units per hectare.** Divide the number of homes by the site area to see how crowded the estate is likely to feel. 2. **Ratio against neighbours.** Check the Master Plan for nearby plots. A low-rise neighbour zoned for a higher ratio may be redeveloped into something taller. 3. **Facilities per household.** A large estate with many facilities and a small estate with few can offer a similar amount per home.
The district pages group projects that share a postal district, which makes side-by-side comparison of these figures easier.
Last updated