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The residual is the answer. Everything else is evidence.

Viability appraisal software for planning consultants, valuers and local authorities in England. Every assumption names its source and date, and every saved appraisal reproduces exactly, so the number you defend at committee, appeal or review is the same one years later.

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Harbour Lane, Manchester: an illustrative site planA 1.1 hectare site inside a red line, between Wharf Street and the dock. Two terraces of three-bed houses, sixteen in all, face a new street and Harbour Lane. A quayside block holds twenty two-bed apartments, and a second block seven affordable rent and five shared ownership apartments. Open space with trees sits in the middle.THE DOCKHARBOUR LANEWHARF STREETN02550 m
  • 16 houses
  • 20 apartments
  • 7 affordable rent
  • 5 shared ownership
  • The red line: 1.1 ha

Residual surplus

£297,632

NPV £255,860 · IRR 35.9% · 48 homes

Reproduced exactly from the version pinned for planning

Harbour Lane is an invented demonstration scheme. Every figure was calculated by the Residual engine.

What's left is the answer.

Harbour LanePlanning submission

How Harbour Lane's residual is built up
Revenue£13,710,543
less costs(£10,887,152)
less finance(£493,243)
less developer return(£2,032,516)
Residual surplus£297,632
Drawn to scale, the answer is 2.2% of revenue.
The Working panel of Residual's appraisal workspace for the demonstration scheme Harbour Lane. It shows a residual surplus of £297,632, an NPV of £255,860, an IRR of 35.9% and an MIRR of 22.6%, then the build-up: revenue of £13,710,543 less costs of £10,887,152, finance of £493,243 and a developer return of £2,032,516. Below, the Assumptions in use list opens with the affordable rent share, 80% of market rent.

Every number shows its working.

A spreadsheet can produce a number. It can't tell you where each input came from, when it was true, or whether the result has quietly drifted. Residual can.

Trail Affordable rent, share of market rent

  1. Source

    MHCLG: Policy statement on rents for social housing

    80.0% of market rent, published, effective 1 April 2011

  2. Affordable rent apartments

    £175 market rent a week × 80.0%
    £140 a week
    £140 × 52 weeks, less £420 service charge
    £6,860 a year
    Less £1,050 management and maintenance a year
    £5,810 a year
    £5,810 ÷ 5.0% yield
    £116,200 per home
    7 homes × £116,200
    £813,400

  3. Effect on the residual

    £813,400

One engine, three questions.

The three appraisal modes
ModeThe question it answersIt returns
Viability assessmentDoes this scheme work at this land price?The surplus or (deficit).
Residual land valueWhat can we afford to pay for the land?The land value that brings the surplus to zero.
Affordable housing valuationWhat is the affordable element worth?The value of the affordable homes.

Identical inputs always return an identical result.

See where viability breaks, before anyone else does.

Take 10% off capital values and a surplus of £297,632 becomes a deficit of £884,323.

Residual's sensitivity screen for Harbour Lane. A summary says the base surplus of £297,632 first turns to a deficit at capital values minus 5%, giving (£291,079), and at build cost plus 5%, giving (£183,929). A two-way grid shows the surplus with each of six inputs moved by 2.5, 5 and 10% either way. Below it, What moves the surplus most ranks capital values, then build cost, as the largest moves.

Scroll sideways to see the whole screen.

Reports people can check.

Every report is built from a saved, signed-off version, so it reproduces exactly. Export to PDF, Word or HTML. Every assumption is footnoted.

Board paper · Viability statement · One-page summary · GLA-style output

The first page of a Residual board paper for Harbour Lane, with the Residual masthead, the scheme details including the planning authority, Manchester, six headline figures (a surplus of £297,632, NPV £255,860, IRR 35.9%, total revenue £13,710,543, total cost £10,887,152 and developer return £2,032,516), the purpose, and the start of the financial appraisal table.

Signed off Priya Raman, Development director (fictional)

Sid's panel inside Residual. A user asks 'Where do the numbers come from?' and Sid answers that every figure traces to where it came from: the Working panel says which engine calculated it and lists the Assumptions in use, each with its source, effective date and confidence tier. The topic Reading the result is shown beneath, and the footer says Sid doesn't calculate figures.

Built-in help that shows its source.

Sid doesn't calculate figures. Every number comes from the engine, and anything Sid reads from a document is shown for you to check before it's used.

Questions people ask

  • Sid

    Residual land value (RLV) is the price you could pay for the land and still make the scheme break even — what's left for land after all build costs, fees, finance and the developer's required return are met. In Residual land value mode the engine solves for it; it's typically compared against a benchmark land value.

    Source: Concepts & glossaryResidual guide

Make your next viability case easy to defend.

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