What is a good efficiency ratio for a residential project?

It depends entirely on typology. Low-rise plotted and villa development can exceed ninety percent, mid-rise apartments commonly sit in the high seventies to mid eighties, and high-rise towers with large cores, refuge floors and extensive amenity fall lower. Compare against your own comparable schemes rather than a published benchmark.

Should amenity area be treated as saleable?

Only if you are actually selling it. Clubhouses, management offices and utility blocks are usually built and handed over rather than sold, so they consume construction cost without generating direct revenue — although they may support the achievable rate.

Does higher loading increase profit?

It increases quoted area and therefore headline revenue at a given rate, but buyers in informed markets price on carpet area. Raising loading generally shows up as a lower achievable rate rather than as additional profit, which is why sensitivity on rate matters more than the loading assumption.

What efficiency should I assume for my scheme?

None from us. Efficiency is an output of your service cores, circulation, amenity provision and building type, and it varies widely between low-rise, tower and commercial schemes. Enter your own assumptions here, then replace them with the architect's measured area statement as soon as one exists.

Saleable area and efficiency calculator for a development

Take a total built area down to what you can actually sell after services, circulation and amenity, then back up to the super built-up figure you would quote.

Scheme

Total built-up areayou enter

Unityou enter

Non-saleable

Services and plantyou enter

Electrical rooms, pump rooms, tanks, refuge areas, shafts.

Circulation and coresyou enter

Lobbies, corridors, staircases, lift cores.

Amenity and non-sale blocksyou enter

Amenity unityou enter

Quoting

Loading applied when quotingyou enter

Result — calculated from your inputs

Net saleable area1,62,000 sq ft

Project efficiency81%

Quoted super built-up2,02,500 sq ft

From built-up to saleable

Total built-up area2,00,000 sq ft

Less services and plant− 8,000 sq ft

Less circulation and cores− 24,000 sq ft

Less amenity blocks− 6,000 sq ft

Net saleable1,62,000 sq ft

Continue to a full site assessment

A calculator answers one question. A DevPartner assessment carries planning capacity, programme, cost, revenue, deal structure and cash flow through one deterministic model and freezes a versioned decision report.

Nothing from this calculator maps into the assessment intake, so you will start from a blank site. No opportunity is created until you save one.

Continue to a full site assessment See a sample decision report

How this calculator works

services    = total × services %
circulation = total × circulation %
net saleable= total − services − circulation − amenity
efficiency  = net saleable ÷ total × 100
quoted super= net saleable × (1 + loading %)

You enter: A value you supply. Nothing is assumed for you.
Calculated: Arithmetic on your inputs, shown in the working.
Assumption: A factor or allowance you can change — mix ratios, wastage, dry-volume factors.
Approximation: Geometry or method that approximates reality; labelled wherever used.
Verify locally: Planning parameters, statutory rates and structural design must come from the authority or a qualified professional.

Efficiency is where schemes quietly lose money

Efficiency — net saleable area divided by total built area — is the ratio that converts planning capacity into revenue. A scheme at eighty-four percent efficiency and one at seventy-six percent, built on the same plot with the same FSI, differ by roughly ten percent in revenue while carrying almost identical construction cost.

Efficiency is set by the plan: core placement, corridor length, single- versus double-loaded circulation, and how much amenity the market expects. It is decided at concept design and is expensive to recover later, which is why it belongs in a feasibility model rather than in a post-design review.

Quoted area is not saleable area

Net saleable area is real space that a buyer occupies. Quoted super built-up area is that space grossed up by a loading factor. Revenue is calculated on the quoted figure multiplied by the rate, so a change in loading changes revenue without changing a single square foot of construction — which is exactly why loading is scrutinised by buyers and regulators.

Model both. Keep net saleable for cost and design decisions, and quoted area for pricing and revenue. Confusing the two is one of the most frequent errors in early appraisals.

Worked example

A scheme with 100,000 sq ft of built-up area loses 5% to services and 10% to circulation, plus 5,000 sq ft of amenity block. Net saleable is 80,000 sq ft, an efficiency of 80%. Quoted at 20% loading the sellable super built-up becomes 96,000 sq ft.

A five-point drop in efficiency removes 5,000 sq ft of sellable product from the same construction cost — usually a larger swing than the sales rate assumption everyone argues about.

Mistakes in saleable area

Applying an efficiency ratio borrowed from a different building type. Tower efficiency, low-rise efficiency and commercial efficiency are not interchangeable.

Selling amenity area twice — once as an amenity and once inside the loaded super built-up.

Assuming loading can be raised indefinitely to fix a weak scheme. What is quotable is constrained by law, by lenders and by what buyers accept.

Limits of this calculator

Efficiency here is the output of your service, circulation and amenity assumptions, not a benchmark supplied by DevPartner. Replace the inputs with your architect's measured schedule as soon as one exists.

Revenue also depends on mix, phasing and absorption, none of which this page models.

Frequently asked questions

What is a good efficiency ratio for a residential project?: It depends entirely on typology. Low-rise plotted and villa development can exceed ninety percent, mid-rise apartments commonly sit in the high seventies to mid eighties, and high-rise towers with large cores, refuge floors and extensive amenity fall lower. Compare against your own comparable schemes rather than a published benchmark.
Should amenity area be treated as saleable?: Only if you are actually selling it. Clubhouses, management offices and utility blocks are usually built and handed over rather than sold, so they consume construction cost without generating direct revenue — although they may support the achievable rate.
Does higher loading increase profit?: It increases quoted area and therefore headline revenue at a given rate, but buyers in informed markets price on carpet area. Raising loading generally shows up as a lower achievable rate rather than as additional profit, which is why sensitivity on rate matters more than the loading assumption.
What efficiency should I assume for my scheme?: None from us. Efficiency is an output of your service cores, circulation, amenity provision and building type, and it varies widely between low-rise, tower and commercial schemes. Enter your own assumptions here, then replace them with the architect's measured area statement as soon as one exists.