How many tonnes of steel or aluminium is the United Kingdom (UK) Carbon Border Adjustment Mechanism (CBAM) £50,000 threshold?

No single tonnage fits every product. The UK limit is a value of £50,000, counted as customs value, not a weight. The tonnes that reach it depend on what each tonne is worth. Weight matters later, when the emissions on the return are worked out.

Value, not weight

Think of a shopkeeper's takings: it is what customers paid, not how many boxes left the shop. The UK CBAM limit works the same way.

The policy summary from HM Revenue and Customs (HMRC) says the value of a CBAM good is "the same value that is used, or would be used, to calculate any applicable customs duty". The registration guidance sets the limit at CBAM goods "worth £50,000 or more".

Where weight does matter

HMRC's emissions page says embodied emissions are worked out by multiplying the weight of the imported good by its emissions intensity, in tonnes of carbon dioxide equivalent (tCO2e) per tonne, or by the default value. HMRC's records page says weight is the net mass in kilograms (kg), excluding packaging.

So weight, with the emissions intensity or default value, decides the emissions on the return. Value decides whether the buyer must register.

Why one tonnage cannot be quoted

• A tonne of low-value goods adds little to the total. A tonne of high-value goods adds a lot.
• The limit is the buyer's total across all its suppliers and all its CBAM goods, not your shipments alone.
• The buyer checks the past 12 months and, on any day, the next 30 days.

What this means for a supplier

• Ask your buyer for its own running total instead of guessing from your invoices.
• Put the customs value on every invoice line. The buyer needs it for its 12-month check.

Three example values per tonne

• At £600 per tonne: 50,000 / 600 = 83.3 tonnes reach £50,000
• At £900 per tonne: 50,000 / 900 = 55.6 tonnes
• At £2,500 per tonne: 50,000 / 2,500 = 20.0 tonnes

These per tonne values are examples for the sums. They are not market prices for any product.

What Senseible does here

Senseible reads fuel invoices and electricity bills into dated, fingerprinted records. It does not file UK CBAM returns, work out your buyer's registration date or check commodity codes. Those stay with the importer and HMRC.

• How the £50,000 value is counted
• Exactly £50,000: does it trigger registration?
• Net weight on the return
• How an emissions intensity is worked out
• UK CBAM for Indian exporters

Sources: HMRC, Carbon Border Adjustment Mechanism (CBAM): Policy summary (updated 2 November 2026), HMRC, Work out the date you will need to register for CBAM (updated 16 July 2026), HMRC, Getting the emissions intensity when importing CBAM goods (updated 16 October 2026), HMRC, Keeping records for CBAM (updated 3 November 2026)

Last reviewed 2026-11-07. Value rule from HMRC's policy summary (updated 2 November 2026) and registration guidance (updated 16 July 2026). The per tonne values are examples only.