Building Safety Levy for England: Estimator Tool
The Building Safety Levy for England comes into force on 1 October 2026.
The Levy, which is designed to contribute to the cost of remediation of unsafe buildings, will be charged on new buildings constructed in England. It aims to collect £3.4 billion from UK home builders for building safety-related purposes. It will be charged before completion of building work and occupation of buildings and collected by local authorities.
All developments which deliver at least 10 additional dwellings (or 30 additional purpose-built student accommodation bedspaces) will be liable to pay the levy, which is calculated based on net additional chargeable floorspace. Chargeable floorspace is any floorspace created within ordinary residential dwellings and purpose-built student accommodation (PBSA), as well as a share of the floorspace in any communal area, proportionate to the share of ordinary resident units or PBSA bedspaces using that communal space.
Thus, if a new development consisted of a single building of 20 identical flats, of which 16 were ordinary residential flats and 4 were social rent flats, with a shared hallway, the development would be in scope for the Levy, and the chargeable floorspace would be the total floorspace of the 16 ordinary residential flats, plus 80% (i.e., 16/20) of the floorspace of the hallway.
To support CIAT members and affiliates in calculating Levy liabilities, CIAT has developed a Building Safety Levy estimator tool, which can be downloaded below. Please note, this tool only provides an estimate of liabilities, designed to support you. The tool should be used alongside relevant legislation and guidance, including:
N.B., You must be logged in as a member or affiliate to download the estimator tool.
Important information
This estimator tool has been developed by CIAT to provide an indicative estimate of the Building Safety Levy that may apply to a development in England. It is provided for general information and guidance only.
The tool does not determine whether a development is liable for the Building Safety Levy and does not calculate or confirm the amount legally payable. The relevant collecting authority is responsible for determining the levy in accordance with the Building Safety Levy (England) Regulations 2025, as amended, and the circumstances of the individual development.
The estimate produced will depend on the accuracy and completeness of the information entered and may differ from the amount determined by the collecting authority. Particular care should be taken where a development covers multiple local authorities or where it includes multiple buildings, mixed uses, exempt accommodation, shared communal areas, existing residential floorspace, previously developed land or other circumstances which may affect the calculation.
Users should refer to the current Building Safety Levy Regulations and Government guidance and, where appropriate, seek independent professional or legal advice. CIAT members and affiliates remain responsible for exercising their own professional judgement and for ensuring that advice and services provided to clients are appropriate to the circumstances of the project.
Levy rates, legislation and Government guidance may change. The estimator tool reflects the information available at the date stated and users should check that they are using the latest version.
CIAT accepts no responsibility for decisions made or costs incurred solely in reliance on an estimate produced by this tool. The final levy amount, including the application of any exemption or discounted rate, will be determined by the relevant collecting authority.
Any questions or feedback regarding the Levy or the estimator tool should be directed to [email protected]
