Units, off-site delivery and credits · England
BNG units
BNG units are biodiversity units, the standardised measure of habitat value produced by England's statutory biodiversity metric and the currency in which the 10% biodiversity net gain is delivered. Developers create units on site, buy registered off-site units from habitat banks, or as a last resort buy statutory biodiversity credits from government at £42,000 to £650,000 per credit. Biodiversity Net Gain Hub explains the market and lists providers; it does not sell or broker units.
Units versus credits
| Route | What it is | Who provides it | Duration | Price signal |
|---|---|---|---|---|
| 1. On-site units | Habitat retained, created or enhanced inside the red line boundary | The developer | Significant on-site gains managed for 30 years | Design and maintenance cost |
| 2. Off-site units | Units generated on a registered biodiversity gain site elsewhere in England and allocated to the development | Land managers, habitat banks, via brokers | 30-year legal agreement | Private market; varies by habitat and location |
| 3. Statutory credits | Last-resort credits sold by government; revenue funds habitat creation | Defra / Natural England | n/a to buyer | £42,000–£650,000 per credit; 2 credits per unit |
This order is the biodiversity gain hierarchy. Developers may combine routes but must follow the steps in order and evidence why earlier steps were insufficient. From 6 August 2026, small ("minor") developments may consider on-site and off-site delivery at the same time.
Delivery options at a high level
On-site
Retaining existing habitat is the cheapest unit there is, because it carries no difficulty or temporal discount. Creating habitat on site counts, but the metric discounts it for the years it takes to reach target condition and for how hard the habitat is to establish. Significant on-site gains must be secured by condition, planning obligation or conservation covenant for 30 years.
Off-site
A land manager registers land on the national biodiversity gain sites register, signs a 30-year legal agreement with a responsible body or local authority, and calculates units with the statutory metric. When a developer buys, the allocation of those units to the development is recorded on the register. Off-site units are further discounted by a spatial risk multiplier the further they are from the development, so local units are worth more to the buyer. Habitat banks aggregate this into ready-made supply; brokers match buyers with sellers.
Statutory credits
Only when on-site and off-site routes are shown to be unavailable. Defra sets prices in tiers by habitat distinctiveness and type, reviews them every six months with at least 10 weeks' notice of change, and applies a spatial risk multiplier that doubles the number of credits needed. VAT is not charged on credits.
| Tier | Price per credit | Examples |
|---|---|---|
| A1 | £42,000 | All low distinctiveness; medium grassland, heathland and shrub, cropland, urban, individual trees; reedbeds; traditional orchards |
| A2 | £48,000 | Medium woodland; lowland and upland calcareous grassland; lowland and upland heathland; open mosaic habitats |
| A3 | £66,000 | Wet woodland; upland birchwoods; littoral mud and mixed sediments |
| A4 | £125,000 | Priority ponds; lowland mixed deciduous woodland; saltmarsh; coastal lagoons; floodplain wetland mosaic |
| A5 | £650,000 | High, low, moderate alkalinity, marl and peat lakes |
| H | £44,000 | All hedgerows |
| W | £230,000 | All watercourses |
Market caveats
- Statutory credit prices are a ceiling signal, not a guide to off-site unit prices, which are negotiated privately.
- Trading rules mean units are not fully interchangeable: losses of medium and higher distinctiveness habitat must be compensated like-for-like or better.
- Location matters: the spatial risk multiplier rewards gain sites in the same local planning authority or National Character Area.
- Supply is uneven across England; check the biodiversity gain sites register for registered sites near you.
- Legal agreements bind land for 30 years; sellers need specialist advice before committing.
Find providers (listings only)
The BNG directory lists habitat banks, brokers, consultant ecologists and legal advisers. Biodiversity Net Gain Hub is not a party to any unit transaction: we do not hold, sell, broker or take commission on biodiversity units or statutory credits. Use the directory to shortlist, then contract directly with the provider.
Frequently asked questions
What is the difference between BNG units and BNG credits?
Biodiversity units are the metric's measure of habitat value and are what developers must deliver: on site, or by buying off-site units from a registered biodiversity gain site. Statutory biodiversity credits are a last-resort product sold by the government when on-site and off-site options are not possible; they are priced by Defra, carry a spatial risk multiplier of 2 credits per unit, and are deliberately expensive so they do not undercut the private market.
How much is a biodiversity unit worth?
Off-site biodiversity units are traded privately and prices vary by habitat type, location and market conditions; GOV.UK states that statutory credit prices are not guideline prices for off-site units. Statutory credits themselves cost from £42,000 per credit (tier A1, low and most medium distinctiveness habitats) to £650,000 (tier A5, certain lakes), with hedgerow credits at £44,000 and watercourse credits at £230,000, per the GOV.UK prices page updated 2 June 2026. Two credits are needed per unit.
Who can sell biodiversity units?
Any land manager in England can sell off-site biodiversity units if they register the land as a biodiversity gain site on the national register, enter a legal agreement (planning obligation or conservation covenant) with a local authority or responsible body lasting at least 30 years, and calculate the units with the statutory biodiversity metric. Sales are recorded by allocating units to a specific development on the register.
Does Biodiversity Net Gain Hub sell biodiversity units?
No. Biodiversity Net Gain Hub is an educational hub with a directory of third-party providers. It does not own gain sites, hold or sell units or credits, act as broker or principal in any transaction, or take a commission on unit sales. Enquiries submitted through the directory are passed to listed firms.
Sources
Official guidance this page relies on, with the "last updated" date shown on each source when this page was written. Always check the live GOV.UK page before acting.
- Understanding biodiversity net gain — GOV.UK (Defra) (updated 14 July 2026)
- Statutory biodiversity credit prices — GOV.UK (Defra) (updated 2 June 2026)
- Search the biodiversity gain sites register — GOV.UK (updated 2 June 2026)
- Biodiversity net gain: guidance for developers, land managers and authorities — GOV.UK (updated 27 August 2026)