Impact calculator

This calculator is aimed at developers wishing to obtain an estimate of how many conservation credits they might need to purchase in order to compensate or offset for the impacts caused by a particular development. It may be possible to reduce this impact by enhancing other habitats on-site. The value that can be generated will depend on the types of habitat present, their condition and whether habitats will be created or restored.

The calculator is based on a Government metric, tested by Defra in 6 county-sized pilots in 2013/2014 and by other local authorities who wanted to use it. The metric design draws upon offsetting metrics that have already been used for decades in other countries (e.g. Australia).

When entering the size of your site, please only enter values rounded up or down to whole numbers, for example, an area of 3.7 ha will be rounded up to 4 and an area of 3.2ha be rounded down to 3.

Please note This information relies on certain assumptions. It has only been designed to give a useful general indication of the impact in biodiversity units of your site. It is important you always get a specific assessment which includes any avoidance, mitigation and compensation works, as this will reduce your offset, before acting on the information. We cannot accept responsibility for any errors.

We encourage you to contact us for a more accurate assessment of impacts, potential for on-site enhancements and how offsetting works. Our vast experience in providing impact assessment reports, using our in-house calculator, gives developers and planning authorities confidence in the calculations that we provide to accompany planning applications.


Biodiversity value: 0 units

Total biodiversity value

Biodiversity: 0 units. Linear: 0units