Average CIL Charges by Development Typology
CIL costs vary drastically across different construction typologies:
• Single Replacement Dwelling: If an old 100 m² bungalow is demolished and replaced with a 220 m² house, CIL is charged only on the net gain of 120 m² (approx. £14,000–£28,000).
• Residential Extension Over 100 m²: An extension adding 110 m² of GIA triggers full CIL liability on all 110 m² unless a statutory residential extension exemption (Form 9) is granted prior to commencement.
• Commercial to Residential Conversion (Class MA): If the commercial building was lawfully occupied for 6 months in the last 3 years, net additional floorspace is zero, resulting in a £0 CIL bill.
Benchmark CIL Costs Across UK Regions for a 150 m² Detached Home
| Geographical Region | Average Local CIL Rate (£/m²) | Mayoral CIL | Estimated Total CIL Bill |
|---|---|---|---|
| Inner London (Zone 1/2) | £350 – £650 / m² | £80 / m² (MCIL2) | £64,500 – £109,500 |
| Outer London (Zone 4/5/6) | £150 – £300 / m² | £60 / m² (MCIL2) | £31,500 – £54,000 |
| South East & Home Counties | £120 – £280 / m² | £0 | £18,000 – £42,000 |
| South West (Bath, Bristol, Exeter) | £100 – £220 / m² | £0 | £15,000 – £33,000 |
| East of England (Cambridgeshire) | £90 – £200 / m² | £0 | £13,500 – £30,000 |
| Midlands (Birmingham, Solihull) | £50 – £150 / m² | £0 | £7,500 – £22,500 |
| North & Wales (Leeds, Sheffield) | £0 – £90 / m² | £0 | £0 – £13,500 |