CIL Calculator

The Spelthorne Borough Council (SBC) Community Infrastructure Levy (CIL) Calculator has been developed to assist developers and landowners in calculating an indicative charge for CIL. It is not intended to provide a definitive answer; this will be calculated by SBC officers when the application is submitted for approval or prior approval.  No allowance is made for exemptions which will be calculated separately once an application for charitable relief or social housing relief is submitted by the applicant/landowner.

Please note:

The calculator may not be compatible with software used on Macs; if this is the case please refer to the CIL Regulations 2010 (as amended) for the calculation method.

All CIL Calculations are linked to Indexation. This is to keep the levy responsive to market conditions. Indexation is a requirement of the CIL Regulations and has to be calculated using the All-in Tender Price Index (published by the Building Cost Information Service BCIS).

Calculation of charge

CIL is charged on the net additional gross internal floor area of a development.  Where buildings are demolished, the total of the demolished floorspace will be off-set against the floorspace of the new buildings, providing the buildings were in lawful use prior to demolition.

In this context, a building is considered to be in lawful use if a part of that building has been in use for a continuous period of at least six months within the period of 3 years ending on the day planning permission first permits the chargeable development.

To use the calculator, you will need to know:

  • the charging zone in which the development is proposed; a map is provided to help
  • the gross internal floor area (m2) in lawful use:

a.    To be demolished
b.    To be retained for different uses

  • the gross internal floor area (m2) proposed for different uses; definitions of the different uses are provided to help

The calculation of the chargeable amount of CIL to be paid for a development proposal is set out in Regulation 40 of the CIL Regulations 2010 and the Amendment Regulations 2011, 2012, 2013 and 2014. For details of the charge calculation, please refer to these Regulations.

Please see the attached information on pdf icon How GIA is measured [112kb].

excel icon CIL Calculator [76kb]

Paying by instalments

The Council has agreed an pdf icon CIL Instalment Policy [110kb]to allow for CIL payments to be spread over the period of a development.  The instalments calculator will indicate how the indicative CIL charge may be payable in fixed instalments.