CBAMReturn

Rate watch · no official rate exists yet

The UK CBAM rate: what's known, what's coming, what to budget.

Every “your CBAM bill will be £X” number you see today rests on an assumption about the rate — because HMRC has not yet published one. This page tracks the rate story from primary sources only, and says plainly which numbers are official and which are scenarios.

How the rate is set (this part is law)

Under the made regulations (S.I. 2026/809), each quarter's sectoral rate starts from the mean UK ETS auction clearing price of the preceding quarter, reduced to reflect the free allocation UK producers in that sector still receive — a discount that shrinks each year as free allocation phases out. The Treasury publishes the rate at the start of each quarter from January 2027; your Q1 2027 rate is therefore set by Q4 2026's auctions.

The timeline

Autumn 2026Illustrative CBAM rate published (HMRC's stated intention) — the first official number anyone can budget with.
Oct–Dec 2026Q4 auctions run — their mean sets the first real rate.
Early Jan 2027First live quarterly sectoral rates published; CBAM in force.
Quarterly afterNew rates at each quarter's start, from the preceding quarter's auctions.

What public price data shows

The official monthly average UK allowance price published on gov.uk (a futures-settlement series — an indicator of where the market is, not the statutory auction mean itself):

MonthAvg price (£/tCO2e)
Dec 202562.13
Jan 202668.26
Feb 202650.83
Mar 202639.46
Apr 202646.82
May 202652.41
Jun 202657.02
Jul 202658.68

The shape matters more than any single month: a winter spike, a spring slump, and a steady climb since April — July was the highest month since January. Whatever Q4 2026 averages is, near enough, your first CBAM rate's starting point.

Know the moment it's real

One email when the illustrative rate publishes, one when each real quarterly rate lands. No spam, unsubscribe anytime.

Want the rate applied to your actual imports? Run the liability preview — every line shows which rate it used and why.

Basis: FA 2026 s.149; S.I. 2026/809 regs 3–4 (made); HMRC policy summary (revised 16 Jul 2026). Rules basis draft-2; last reviewed 2026-08-31. General information, not tax advice.