BNG Calculator
Statutory Biodiversity Metric v4.0 (JP039)· Defra GOV.UK guidance, last updated 2 June 2026· NSIP extension live 2 November 2026· Reviewed 6 August 2026

On-site vs off-site vs statutory: which BNG route wins

Off-site units typically win on cost and risk for medium-distinctiveness deltas; on-site wins for small deltas under 3 BU; statutory credits never win, they are the punitive backstop.

Awaiting MCIEEM peer review · CIEEM (Chartered Institute of Ecology and Environmental Management)

What each route is priced from

Route A
On-site delivery
Your habitat creation and 30-year management plan
Route B
Off-site units
A habitat bank's quote (no public rate card)
Route C
Statutory credits
£84,000 to £1.3m per unit (2 credits x £42,000 to £650,000)

Scoring matrix

Hierarchy change from 6 August 2026

The regulations in force since 6 August 2026 relax the biodiversity gain hierarchy for developments over 0.2 ha: a developer may now choose to go straight to off-site delivery in the first instance, rather than being required to exhaust on-site options first. On-site delivery remains generally preferred by LPAs on planning-acceptability grounds, but off-site is no longer a fallback of last resort before statutory credits. This confirms the route logic below.[S16]

Decision tree

A small delta at low or medium distinctiveness with simple habitat creation usually suits on-site delivery. A large delta, high distinctiveness, or a habitat with a very high difficulty multiplier usually points off-site. No compliant supply anywhere: statutory credits, the last resort.[S1]