Development potential: buildable area, unit yield and parking
Permissible built-up area is only the beginning. This page turns the planning envelope into the things that actually drive a scheme — saleable area, how many units it yields at your target size, and how much basement the resulting parking demand consumes. Every input is yours; nothing is inferred from a database of rules.
Site, planning and product inputs
Road widening, reservation or OSR handover
Saleable area per unit your target buyer wants
As required by the local norm or your market
Including aisles, ramps and circulation
Potential
The arithmetic
saleable area = permissible BUA × efficiency % unit yield = floor(saleable area ÷ average unit size) parking bays = ceil(unit yield × bays per unit) parking area = parking bays × area per bay basement levels = parking area ÷ ground footprint
The last line is the one that catches schemes out. Parking is built at the most expensive rate per square foot in the project and sells for the least, so a site whose footprint forces three basement levels instead of one can lose its margin without a single change to the sales rate.
How to read the output
- Unit yield vs. plate efficiency. If yield divided by indicative floors gives an implausible number of units per floor, the massing does not work and the area figure is fiction.
- Basement levels above ~2. Check excavation, shoring, water table and ramp geometry before you accept the cost.
- Unit size against the market. A yield that only works at a unit size your market does not absorb is a pricing problem, not a capacity one.
From potential to a decision
Potential is capacity, not viability. Once the area and parking are settled, cost the scheme, price it against comparable transactions and test what the land can support. The land feasibility sequence sets out the full order.
What to work out next
- Construction cost calculator
Cost the built-up and basement area you just derived.
- Residual land value calculator
Work back to the land price this potential supports.
- FSI / FAR calculator
Revisit the planning envelope on its own.
- Developer feasibility
The viability measures a developer applies before committing.
Frequently asked questions
- What does 'development potential' actually mean?
- It is the bridge between what the planning framework permits and what you can realistically build and sell: permissible built-up area converted into saleable area, a unit count at your target unit size, and the parking that unit count obliges you to provide.
- Why is unit yield lower than built-up area divided by unit size?
- Because only saleable area sells. Cores, corridors, services, refuge areas and amenity space consume built-up area, and the super built-up convention you adopt determines how much of that is chargeable. Yield should always be derived from saleable area, never from FSI-counted built-up area.
- How much area does one parking bay really consume?
- A bay is roughly 135 sq ft, but with drive aisles, ramps, columns and services the effective consumption in a basement is typically much higher. Use the figure your own recent basements achieved rather than a textbook bay size — the difference between 135 and 300 sq ft per bay changes the basement count and the cost materially.
- Does more FSI always mean more profit?
- No. Additional FSI that forces an extra basement level, a taller structural system or a unit mix the local market does not absorb can cost more than it earns. Test the increment in the residual and cost tools rather than assuming density is value.
- Can I use this for commercial or mixed-use schemes?
- The area arithmetic holds, but commercial parking norms, efficiency conventions and revenue basis differ from residential. Treat the output as a first screen and set the efficiency, unit size and parking inputs to your own commercial benchmarks.
Take this from a calculator to a decision
A single-page calculator cannot phase a programme, model cash flow, compare structures on one base or freeze a report. DevPartner's deterministic engine does — with every assumption traced back to the value you entered.