Community Infrastructure Levy
CIL is the most commonly miscalculated development cost.
Calculate CIL liability from your postcode
Wrong floorspace basis. Wrong zone. Indexation ignored. Exemptions missed. PlanSureAI calculates CIL liability automatically — charging schedule, net additional floorspace, zone, exemptions, and instalment timing — and puts it inside the viability model where it belongs.
Calculate your CIL liability free
Enter a postcode. Get your CIL zone, rate and total liability in seconds.
Run a free postcode checkWhat is the Community Infrastructure Levy?
The Community Infrastructure Levy (CIL) is a charge on new development in England and Wales, levied by local planning authorities under the Planning Act 2008. It is calculated per square metre of net additional floorspace created and is used to fund local infrastructure — roads, schools, parks, and community facilities.
Unlike Section 106 planning obligations — which are individually negotiated between developer and local authority — CIL is a standardised, non-negotiable charge based on a published charging schedule. The rate varies by development type, by zone within an authority, and by authority. Not every authority has adopted CIL; some still rely entirely on S106 for infrastructure contributions.
CIL is payable on commencement of development. Failure to comply with CIL payment requirements — including late payment or failure to claim available exemptions correctly — triggers surcharges and can result in stop notices.
CIL vs S106 — not the same thing
Both CIL and S106 are costs associated with planning permission. Both belong in the viability model. They work differently and the distinction matters for lenders.
CIL
- Standardised — rate set in published charging schedule
- Non-negotiable — applies automatically to qualifying development
- Calculated on net additional floorspace × applicable rate
- Paid in instalments — commencement and occupation triggers
- Indexed annually — rate at payment differs from rate at consent
- Exemptions must be formally claimed before commencement
Section 106
- Negotiated — agreed between developer and LPA as a condition of consent
- Site-specific — obligations vary by scheme and authority
- Can include affordable housing, highways, ecology, education
- Trigger points vary — commencement, occupation thresholds, completion
- Legal agreement — must be executed before planning permission is granted
- Indexed or fixed — depends on what the S106 agreement specifies
How CIL goes wrong in development appraisals
CIL errors are not rare. They appear in appraisals prepared by experienced developers and in lender-ready evidence packs prepared by experienced brokers. Each of the following can materially affect the lender's assessment of deal viability.
- Gross floorspace used instead of net additional floorspace — the most common error; inflates liability on schemes with existing buildings
- Wrong charging zone — CIL rates vary by zone within a single authority; applying the wrong rate invalidates the entire appraisal
- Exemptions not claimed — self-build, affordable housing units, and charitable use all carry full or partial CIL relief; missing them overstates the liability
- Indexation not applied — CIL rates are indexed annually to the BCIS All-in Tender Price Index; a rate from the charging schedule is not necessarily the rate payable at commencement
- Instalment timing ignored — CIL is paid in instalments triggered at commencement and on occupation; the cash timing affects the finance model, not just the total
- CIL omitted entirely — common on small sites where the assumption is that CIL will be nil; it is not always nil, and the assumption is never evidenced
What PlanSureAI calculates automatically
Enter a postcode. PlanSureAI identifies the local authority, looks up the current charging schedule, and calculates CIL liability for the scheme type and floorspace. Every input is named. Every figure is traceable.
Charging schedule lookup
Local authority charging schedule identified from postcode. Rate applied by development type — residential, commercial, mixed-use. Zone-specific rates where the authority uses spatial charging.
Net additional floorspace
CIL is calculated on net additional floorspace, not gross. Existing floorspace in lawful use at the time of permission is deducted. PlanSureAI applies the correct NIA basis from the scheme spec.
Applicable rate and zone
Where an authority has multiple charging zones, the site postcode is matched to the correct zone. The applicable rate per sqm is confirmed, not assumed from a national average.
Exemptions and reliefs
Self-build exemption, affordable housing relief, and charitable use exemptions flagged where the scheme spec indicates eligibility. Exemptions must be claimed correctly — automatic exemption is not guaranteed.
Instalment schedule
CIL instalment payment dates modelled against the programme — commencement trigger and occupation thresholds. Cash timing sits inside the finance cost model, not as a lump sum at completion.
Indexation to payment date
CIL rates are indexed annually. The rate at commencement is not necessarily the rate in the charging schedule. Indexation is applied to the payment-date figure, not the consent-date figure.
CIL sits inside the viability model — not as a footnote outside it. The liability is calculated before profit is stated. A lender reading the lender-ready evidence pack sees CIL as a confirmed cost, not an assumption.
CIL in the lender-ready evidence pack — §4, not an appendix
Most lender-ready evidence packs either omit CIL entirely or mention it in a footnote without quantifying it. PlanSureAI assembles CIL as part of §4 — the regulatory and infrastructure costs section — alongside S106 obligations, FHBS compliance status, and Building Safety Levy applicability.
The lender sees: the applicable rate, the charging zone, the net floorspace basis, the total liability, the instalment schedule, and whether any exemptions apply. CIL is a line in the cost stack — not a discussion to have after the pack is submitted.
Check CIL liability for your next site
Enter a postcode. PlanSureAI identifies the local authority, looks up the charging schedule, and returns the CIL liability alongside planning risk, S106 obligations, and viability indicators — free, no login required.