toolkit
UK CBAM Readiness Toolkit
A Practical Guide for Importers, Supply Chain Managers and Customs Professionals
Version 1.0 — April 2026
Contents
- What is the UK CBAM?
- UK CBAM vs EU CBAM: Key Differences
- Sectors and Products in Scope
- Timeline: Key Dates and Milestones
- Who is Liable?
- Registration Requirements
- How the CBAM Charge is Calculated
- Reporting Obligations and Data Requirements
- Carbon Price Relief (Overseas Credits)
- Emissions Data: Actual vs Default Values
- Step-by-Step Preparation Checklist
- Supplier Engagement: What Data to Request
- Cost Impact Estimation Methodology
- Penalties and Enforcement
- Where Guidance is Still Pending
1. What is the UK CBAM?
The UK Carbon Border Adjustment Mechanism is a new tax on the embedded carbon in certain imported goods. It takes effect on 1 January 2027.
Its purpose is to ensure that carbon-intensive products imported into the UK face a comparable carbon price to that borne by UK manufacturers under the UK Emissions Trading Scheme (UK ETS). Without CBAM, domestic producers pay a carbon price while overseas competitors do not — creating an incentive to shift production abroad (“carbon leakage”) rather than reduce emissions.
CBAM closes this gap. Importers of specified goods will register with HMRC, report the embodied emissions in their imports, and pay a tax based on the UK ETS carbon price.
Key characteristics:
- Tax-based mechanism — Unlike the EU’s certificate/market-based CBAM, the UK’s version is a straightforward tax administered by HMRC
- No transitional reporting phase — The UK goes straight to a definitive phase with financial obligations from day one
- Direct emissions only at launch — Indirect emissions (from electricity used in production) are deferred until 2029 at the earliest
- Linked to UK ETS — The CBAM rate reflects the UK ETS carbon price, adjusted for free allowances
Source: GOV.UK — Carbon Border Adjustment Mechanism; GOV.UK — CBAM Factsheet
2. UK CBAM vs EU CBAM: Key Differences
If your business also exports to the EU, you may already be dealing with EU CBAM obligations. The two mechanisms share a common goal but differ significantly in design.
| Feature | UK CBAM | EU CBAM |
|---|---|---|
| Type | Tax (administered by HMRC) | Market-based (certificate system) |
| Launch | 1 January 2027 (no transition) | Transitional from Oct 2023; definitive from Jan 2026 |
| Sectors | Aluminium, cement, fertiliser, hydrogen, iron & steel | Same five + electricity + glass & ceramics |
| Electricity | Excluded | Included |
| Emissions scope | Direct only (indirect from 2029) | Direct and indirect |
| Registration threshold | £50,000 imports over 12 months | €150 minimum consignment value |
| First reporting period | Annual (calendar year 2027) | Quarterly (from definitive phase) |
| First return due | 31 May 2028 | Quarterly surrender of certificates |
| Rate setting | Quarterly, per sector, by HMRC | Weekly average EUA auction price |
| Default values | Single default per product | EU-developed benchmarks |
| Penalties | Penalty points (VAT-style) + sector offences | €100/tCO2e + certificate purchase |
Key implication: Businesses importing the same goods into both the UK and EU need separate compliance programmes. The systems are not interoperable at launch.
3. Sectors and Products in Scope
CBAM applies to specific imported goods within five sectors. Products are identified by 8-digit commodity codes published in HMRC’s CBAM goods annexes.
Covered Sectors
| Sector | Examples of Products in Scope | Notes |
|---|---|---|
| Iron & Steel | Pig iron, ferro-alloys, flat-rolled products, bars, rods, tubes, wire | Scrap products generally excluded |
| Aluminium | Unwrought aluminium, bars, rods, profiles, wire, plates, foil | Scrap aluminium generally excluded |
| Cement | Portland cement, aluminous cement, clinker | Covers key clinker and cement products |
| Fertilisers | Ammonia, nitric acid, urea, ammonium nitrate, mixed fertilisers | Broad coverage of nitrogen-based fertilisers |
| Hydrogen | Hydrogen gas | Emerging sector; limited trade volumes currently |
Not in Scope
- Glass and ceramics — Originally proposed but removed in October 2024
- Electricity — Excluded from UK CBAM (included in EU CBAM)
- Refined fuel products — Subject to separate Call for Evidence; may be added later
How to Check
Review your import data against the published commodity code annexes. If you import goods classified under any of the listed codes, you are potentially in scope.
Action: Run a report of all imports by commodity code for the last 12 months. Cross-reference against the CBAM goods list published by HMRC.
Source: GOV.UK — CBAM Policy Summary
4. Timeline: Key Dates and Milestones
| Date | Event |
|---|---|
| Q1 2026 | Technical consultation on draft secondary legislation (closed March 2026) |
| Q2–Q3 2026 | HMRC publishes detailed operational guidance |
| Q4 2026 | Trial CBAM rates published (one quarter before go-live) |
| 1 January 2027 | UK CBAM commences — registration and financial obligations begin |
| 31 January 2028 | Extended registration deadline for first-year importers |
| 31 May 2028 | First annual return due (covering 1 Jan–31 Dec 2027) |
| 1 January 2028 | Quarterly accounting periods begin |
| Q1 2028 onwards | Quarterly returns due within 2 months of period end |
| 2029 (earliest) | Indirect emissions potentially brought into scope |
| ~2036 | Indicative end of 9-year free allocation phase-out for CBAM sectors |
Free Allocation Phase-Out
From 2027, free allocation of UK ETS allowances for CBAM sectors will gradually phase out over approximately 9 years. This means domestic producers will progressively lose their free allowance protection as CBAM provides equivalent border protection.
Source: GOV.UK — CBAM Factsheet; GOV.UK — UK ETS Free Allocation Review
5. Who is Liable?
The liable person is the importer — specifically, the person who:
- Completes the customs declaration for CBAM goods, or
- Has CBAM goods imported into the UK on their behalf
In practice, this is typically the business named as the importer of record on the customs declaration. Tax agents and customs brokers may act on behalf of the liable person but cannot register independently.
Key points:
- The obligation sits with the importer, not the supplier or freight forwarder
- If you use a customs broker to clear goods, you remain liable — not the broker
- Joint ventures and group structures: each importing entity registers separately
- CBAM applies across the entire UK, including Northern Ireland, Crown Dependencies, and the UK Continental Shelf
Source: GOV.UK — CBAM Policy Summary
6. Registration Requirements
Threshold
You must register with HMRC if you meet either of these tests:
- Backward-looking test: You have imported CBAM goods worth more than £50,000 in the preceding 12 months
- Forward-looking test: You expect to import CBAM goods worth more than £50,000 in the next 30 days
Who is Excluded?
HMRC estimates that the £50,000 threshold will exclude over 80% of otherwise-affected importers, with over 70% of those excluded being SMEs. Approximately 10,000 businesses are expected to register.
Registration Timeline
- Standard requirement: Register within 30 days of exceeding the threshold
- First-year extension: For 2027, businesses have until 31 January 2028 to register
- Registration is with HMRC via an online system (details to be published ahead of launch)
Information Required for Registration
- Business name, registered address, company registration number
- EORI number
- VAT registration number (if applicable)
- Expected import weights by sector
- Details of authorised representatives (if any)
Source: GOV.UK — CBAM Policy Summary
7. How the CBAM Charge is Calculated
The CBAM liability follows a three-step formula:
Step 1: Calculate Gross CBAM Charge
Embodied emissions (tCO2e) x CBAM rate (£/tCO2e) = Gross CBAM charge
Step 2: Deduct Carbon Price Relief
If the goods were subject to a qualifying carbon price overseas (e.g., an ETS or carbon tax in the country of origin), the importer can claim Carbon Price Relief (CPR).
CPR = Effective overseas carbon price x Embodied emissions
CPR is capped at the gross CBAM charge — it cannot create a credit.
Step 3: Net CBAM Liability
Net liability = Gross CBAM charge - Carbon Price Relief
CBAM Rate
- Set quarterly by HMRC, per sector
- Reflects the UK ETS carbon price, adjusted for free allowances
- Trial rates will be published in Q4 2026
- The rate is applied per tonne of CO2 equivalent (tCO2e) of embodied emissions
Worked Example
A UK importer brings in 500 tonnes of hot-rolled steel from Country X.
- Default embodied emissions for that product: 1.8 tCO2e per tonne of steel
- Total embodied emissions: 500 x 1.8 = 900 tCO2e
- UK CBAM rate (illustrative): £50/tCO2e
- Gross charge: 900 x £50 = £45,000
- Country X has an ETS with effective price of £10/tCO2e
- CPR: 900 x £10 = £9,000
- Net CBAM liability: £36,000
Note: Actual rates, default values, and CPR eligibility will be published by HMRC. This example is illustrative only.
Source: GOV.UK — CBAM Policy Summary
8. Reporting Obligations and Data Requirements
What You Must Report
Each return must include:
| Data Point | Detail |
|---|---|
| Commodity codes | 8-digit codes for each CBAM good imported |
| Net weight | In kilograms, per commodity code |
| Country of origin | Per consignment |
| Embodied emissions | tCO2e per product (actual verified or default values) |
| Carbon price incurred | Any qualifying overseas carbon price paid (in GBP) |
| CPR claim | Evidence supporting Carbon Price Relief deductions |
Reporting Periods
| Period | Frequency | Return Due |
|---|---|---|
| 2027 | Annual (1 Jan – 31 Dec 2027) | 31 May 2028 |
| 2028 onwards | Quarterly | Within 2 months of period end |
Data Sources You Will Need
- Customs declaration data — commodity codes, origin, value, weight
- Supplier emissions data — actual verified emissions per product (if available)
- HMRC default values — published default emissions intensities (used where actual data is unavailable)
- Overseas carbon pricing evidence — certificates, tax receipts, ETS compliance records
Record Retention
All documentation must be retained for 6 years, covering:
- Import records and customs declarations
- Registration details
- Emissions verification reports
- CPR calculations and supporting evidence
Source: GOV.UK — CBAM Policy Summary
9. Carbon Price Relief (Overseas Credits)
If your goods were produced in a country with a qualifying carbon pricing scheme, you can reduce your CBAM liability.
Qualifying Schemes Must Be:
- Government-administered (not voluntary offset programmes)
- Mandatory for relevant installations
- Publicly transparent regarding rules and pricing
- Verified by accredited, independent bodies
Examples of Potentially Qualifying Schemes
- EU Emissions Trading System (EU ETS)
- National carbon taxes (e.g., in Scandinavian countries)
- Other national or regional ETS programmes
How to Claim
- Obtain evidence of the carbon price paid on the embodied emissions in your goods
- Convert to GBP using applicable exchange rates
- Include the CPR claim in your CBAM return
- Retain supporting documentation for 6 years
Verification
- Actual emissions data: Must be verified by a body accredited under the International Accreditation Forum (IAF)
- CPR evidence: Must be verified by a body accredited under the Global Accreditation Cooperation (GAC)
Note: Approximately 80% of CBAM goods imports originate from countries with some form of carbon pricing. Many importers will be eligible for at least partial CPR.
Source: GOV.UK — CBAM Policy Summary
10. Emissions Data: Actual vs Default Values
Importers can choose between two methods for determining embodied emissions:
Option A: Actual Verified Emissions Data
- Obtained from the overseas producer/supplier
- Must be independently verified by an IAF-accredited body
- More accurate — may reduce liability if the producer has lower-than-average emissions
- Requires supplier cooperation and data sharing
Option B: Default Emissions Values
- Published by HMRC before CBAM commences
- Single default value per product
- Simpler to use — no supplier data needed
- Will likely reflect conservative (higher) estimates
- Best suited for importers who cannot obtain actual data from suppliers
Which Should You Use?
| Scenario | Recommended Approach |
|---|---|
| Large, regular imports from cooperating suppliers | Actual verified data (lower cost potential) |
| Small, irregular imports or uncooperative suppliers | Default values (simpler compliance) |
| Imports from countries with advanced carbon reporting | Actual verified data |
| Imports from countries without established monitoring | Default values |
Practical tip: Start engaging suppliers now. Even if you plan to use defaults initially, building the data pipeline for actual emissions will reduce costs over time as default values may be set conservatively.
Source: GOV.UK — CBAM Policy Summary
11. Step-by-Step Preparation Checklist
Phase 1: Assessment (Now – Q3 2026)
- Identify CBAM goods — Review all import commodity codes against CBAM annexes
- Quantify exposure — Calculate total import value and volume for in-scope goods
- Determine registration obligation — Do you meet the £50,000 threshold?
- Map your supply chain — Identify which suppliers and countries of origin are affected
- Assign responsibility — Designate a CBAM compliance lead within your organisation
- Brief senior leadership — Present the financial and operational impact
Phase 2: Preparation (Q3 2026 – Q4 2026)
- Register for HMRC CBAM updates — Email cbampolicyteam@hmrc.gov.uk
- Review trial CBAM rates (published Q4 2026) and estimate costs
- Engage suppliers — Send data request templates (see Section 12)
- Assess data readiness — Can your systems capture the required data points?
- Evaluate IT systems — Ensure customs/trade management systems can support CBAM reporting
- Decide: actual vs default emissions — Per supplier/product
- Prepare CPR evidence — Identify which imports qualify for Carbon Price Relief
- Budget for CBAM costs — Factor into procurement and pricing decisions
Phase 3: Go-Live (Q1 2027 onwards)
- Register with HMRC (by 31 January 2028 for first-year importers)
- Implement CBAM data capture in import processes
- Monitor quarterly CBAM rates published by HMRC
- Collect supplier emissions data per consignment
- File first return by 31 May 2028
- Pay CBAM liability by the return deadline
- Review and optimise — Continuously improve data quality and CPR claims
12. Supplier Engagement: What Data to Request
Obtaining actual emissions data from suppliers will be critical for managing CBAM costs. Below is a template for initial supplier engagement.
Data Request Template
Subject: UK CBAM — Emissions Data Request
Dear [Supplier Name],
The UK is introducing a Carbon Border Adjustment Mechanism (CBAM) from 1 January 2027. As an importer of your products into the UK, we are required to report the embodied carbon emissions of goods we purchase from you.
To comply with this requirement and minimise additional costs, we need the following information for each product we import:
Product-Level Data Required:
- Product description and commodity code (8-digit HS code)
- Direct emissions intensity — tCO2e per tonne of product (Scope 1 emissions from production)
- Production facility details — Name, location, and capacity of the installation(s) where goods are produced
- Monitoring methodology — How emissions are measured or calculated
- Verification status — Whether emissions data has been independently verified, and by which body
- Carbon pricing — Details of any carbon tax or ETS charges applied to production, including:
- Name of the carbon pricing scheme
- Effective carbon price paid (per tCO2e)
- Evidence/certificates of payment
- Precursor materials — Emissions data for any relevant precursor goods used in production (e.g., clinker in cement, pig iron in steel)
Timeline: We require this data by [date] to prepare for the January 2027 launch.
Please contact [your name/email] to discuss. We are happy to arrange a call to explain the requirements in more detail.
We value our partnership and want to work together to ensure compliance while minimising costs for both parties.
Tips for Supplier Engagement
- Start early — Many suppliers will not be familiar with UK CBAM; allow time for education
- Prioritise by volume — Focus first on suppliers providing the largest volumes of CBAM goods
- Offer alternatives — Explain that if they cannot provide actual data, HMRC default values will be used (which may overstate emissions and increase costs)
- Consider contractual updates — Future procurement contracts should include CBAM data obligations
- Leverage EU CBAM precedent — Suppliers already providing data for EU CBAM may have systems in place
13. Cost Impact Estimation Methodology
Step 1: Identify In-Scope Imports
Pull import data for the last 12 months. Filter for CBAM commodity codes. Record:
- Commodity code
- Country of origin
- Net weight (kg)
- Import value (£)
Step 2: Estimate Embodied Emissions
For each product, multiply net weight by the emissions intensity factor:
Embodied emissions (tCO2e) = Net weight (tonnes) x Emissions intensity (tCO2e/tonne)
Use default values when available (HMRC to publish), or industry averages as proxies until then.
Step 3: Estimate Gross CBAM Cost
Gross cost = Embodied emissions x Estimated CBAM rate
For planning purposes before trial rates are published, use the current UK ETS carbon price as a proxy (approximately £40–60/tCO2e — check latest UKA auction prices).
Step 4: Estimate Carbon Price Relief
For each country of origin, check whether a qualifying carbon pricing scheme exists. If so:
CPR = Embodied emissions x Effective overseas carbon price
Step 5: Calculate Net CBAM Cost
Net cost = Gross cost - CPR
Step 6: Assess Impact
- What percentage of your import costs does CBAM add?
- Which products/suppliers drive the highest CBAM exposure?
- Can any exposure be reduced through supplier changes, sourcing alternatives, or actual emissions data?
- How does this affect your pricing, margins, and competitiveness?
Indicative Cost Benchmarks
| Product | Typical Emissions Intensity | Illustrative CBAM Cost per Tonne |
|---|---|---|
| Hot-rolled steel | 1.5–2.0 tCO2e/t | £75–£120 |
| Primary aluminium | 8–16 tCO2e/t | £400–£960 |
| Portland cement | 0.6–0.9 tCO2e/t | £30–£54 |
| Ammonia | 1.5–2.5 tCO2e/t | £75–£150 |
| Hydrogen | 9–12 tCO2e/t | £450–£720 |
Based on illustrative CBAM rate of £50–60/tCO2e. Actual rates will vary.
Warning: These are planning estimates only. Actual costs will depend on HMRC-published rates, your specific supply chain, and whether you use actual or default emissions data.
14. Penalties and Enforcement
HMRC will enforce CBAM compliance through a penalty regime similar to existing tax frameworks.
Penalty Triggers
- Failure to register when required
- Late or missing returns
- Late payment of CBAM liability
- Errors in returns (inaccurate emissions or CPR claims)
- Non-compliance with information notices from HMRC
- Fraudulent evasion — criminal penalties apply
Penalty Structure
The UK CBAM uses a penalty points system (similar to VAT):
- Points accrue for each compliance failure
- At a threshold, a financial penalty is triggered
- Serious or deliberate non-compliance may attract immediate penalties
Criminal Offences
Fraudulent evasion of CBAM is a criminal offence. HMRC has allocated an estimated £31 million through 2031 for enforcement and compliance monitoring.
Source: GOV.UK — CBAM Policy Summary
15. Where Guidance is Still Pending
Several areas remain subject to further government guidance as of April 2026:
| Area | Status |
|---|---|
| Detailed HMRC operational guidance | Expected ahead of January 2027 |
| Default emissions values per product | To be published before launch |
| Detailed CPR qualifying scheme list | To be confirmed |
| CBAM IT system / registration portal | Under development by HMRC |
| Indirect emissions inclusion | Deferred until 2029 at earliest |
| Refined fuel products | Subject to separate Call for Evidence |
| UK-EU ETS linking and mutual CBAM exemptions | Under negotiation |
| Free allocation phase-out annual schedule | Indicative 9-year trajectory; annual rates TBC |
| Penalty points thresholds | To be set in secondary legislation |
How to Stay Informed
- HMRC mailing list: Email cbampolicyteam@hmrc.gov.uk to subscribe
- GOV.UK consultations page: Monitor draft regulations consultation
- CBAM Joint Industrial Working Group: Industry engagement forum (contact HMRC for membership)
- UK CBAM International Group: For international stakeholders
Disclaimer
This guide is based on published UK government policy documents and consultation responses as of April 2026. It is intended for informational and planning purposes only and does not constitute legal, tax, or regulatory advice. The UK CBAM framework is subject to change as secondary legislation is finalised and HMRC publishes operational guidance. Businesses should seek professional advice tailored to their specific circumstances.
Key GOV.UK Sources: