Southwark SE1 GDV Calculator | London

GDV and CIL working numbers

GDV: 840 to 1350 £/sqft
Mid GDV: 1050 £/sqft
Borough CIL (residential): 598 £/sqm
Mayoral CIL2: Z2

Southwark's third charging schedule took effect on 29 September 2026. Its Annual CIL Rate Summary 2026 (Part 2) sets residential CIL at £598/sqm in Zone 1, £300 in Zone 2 and £74 in Zone 3 for permissions from that date. Zone 1 is the riverside strip from Bankside to London Bridge; the rest of SE1, including Borough, Elephant and Castle and the Old Kent Road, is Zone 2 on the council's 2026 zone map. The figure shown is the Zone 1 rate. Permissions granted from 1 January 2027 index to £615.94 (Zone 1) under Southwark's 2027 summary. Mayoral CIL2 adds £72.73/sqm (Zone 2, 2026-indexed, £60 base).

Local context

SE1 covers Borough, Bermondsey, Elephant and Castle.
Southwark CIL from 29 Sep 2026: Zone 1 (riverside) £598/sqm, Zone 2 (Borough, Elephant, Old Kent Road) £300/sqm, plus Mayoral CIL2 Zone 2 £72.73/sqm (2026-indexed, £60 base).
35 percent affordable threshold applies above 10 units.

Open the workbench

InputsUnits

GIA per unit

sqft

NIA ratio

GDV

£/sqft

Build cost

£/sqm

Prof fees

Contingency

s106 / CIL / BNG per unit

Finance rate

Duration

months

LTGDV cap

Target profit on cost

SDLT on land rate

MAX LAND BID£4,568,111At 20% profit on cost, 9 units, 950 sqft GIA each.

MARGINAL

GDV£7,630,875

Build cost£1,494,911

Prof fees£179,389

s106/CIL/BNG£376,740

Contingency£153,828

Finance interest£157,097

Target profit£472,393

Total costs (excl land)£2,361,966

Senior debt @ LTGDV£4,960,069

PoC10.1%

PoGDV9.2%

LTC71.6%

Sensitivity (PoC %)

Build -5%Build +5%Build +10%Build +15%Build +20%

GDV -15%11%11%12%12%12%

GDV -10%10%11%11%11%12%

GDV -5%10%11%11%11%11%

GDV 0%10%10%11%11%11%

GDV +5%10%10%10%10%11%

Cells show profit-on-cost percentage at each GDV stress / build-cost shock pair. Cells below your target PoC turn amber-warm; cells below 10 percent abort.