HMRC's default figures don't know your mill. That's expensive.
Procurement sees which suppliers will cost you at the border. Finance gets the evidence to prove it to HMRC. One number, before January 2027.
A UK importer of 10,000 tonnes of steel from Turkey using HMRC default emission factors faces
£1,265,000 in gross CBAM liability. Default values are built for the worst-case producer — not yours.
Verified mill data is the only mechanism that moves the number.
8-Step
Reg. 5 Methodology
6-Year
Reg. 16 Audit Spine
Sch. 18
Built Against Schedule 18 Risk
--
Days to Enforcement
The Compliance Problem
Most importers don't know what they owe
CBAM is a border tax with embedded complexity — most finance teams are not ready
Unknown liability
Default emission factors can significantly overstate your liability. Without verified mill data, you're planning around the worst-case figure.
CPR left unclaimed
Carbon Price Relief is available for imports from qualifying ETS countries — but only with documented evidence. Most importers miss it.
Record-keeping gap
Regulation 16 requires 6 years of CBAM records including emissions intensity to 5 decimal places. Almost no importer has this in place.
⏱️
Rolling registration trigger
Registration triggers the moment your trailing 12-month imports cross £50,000 — checked monthly — or when you expect to cross it within 30 days. Normally you register within 30 days of the trigger; 2027 triggers get HMRC's first-year easement to 31 January 2028. Liability and record-keeping run from the trigger date — and data collection must begin 1 January 2027.
Before HMRC publishes rates
How to estimate your CBAM exposure now
01Pull commodity codes and volumes from customs records
02Begin supplier engagement now — request emissions data and carbon price enrolment evidence
03Model conservative, central, and stressed rate scenarios against UK ETS price history
04Update when HMRC publishes its illustrative rate (Autumn 2026) then confirmed Q1 2027 rates
The planning window is now
The businesses that wait will be 12 months behind
Supplier data collection, CPR verification, HMRC registration — none of it can happen overnight. At 5,000t of steel using HMRC default emission factors, switching to verified facility-specific data can reduce gross liability significantly — entirely within your control if you start now. For origins where the effective carbon price is near-zero (Turkey, China, South Korea) or no qualifying scheme yet exists (India), the verification gap — not Carbon Price Relief — is where the savings are.
Forward Planning & De-Risking
Know your number before HMRC does.
AI agents plan and run the forward-modelling workload — liability scenarios, supplier data validation, threshold and rate monitoring — and every client deliverable is reviewed by a named specialist before it reaches you. Not a static calculator. Not a consultancy working from a spreadsheet.
Adaptive data handling
Supplier data rarely arrives clean. What comes back is validated and gap-checked — unit errors, missing precursors, unverified figures all get flagged with a plain-English fix — instead of forcing every mill through one rigid template.
Monitoring that doesn't sleep
The registration trigger is rolling — £50k trailing-12-month, checked monthly, plus a 30-day forward test — and the CBAM rate recalculates quarterly. On the Continuous Compliance retainer, your position is tracked against every change, so you're never planning on stale numbers.
Fast output, human sign-off
The 48-hour board-ready audit is possible because automation assembles the analysis — and a named specialist reviews every figure before it goes out. Direct access to jason@cbamproof.co.uk is expert oversight on top of the automation, not a substitute for it.
Free CBAM Calculator
Your indicative CBAM liability in 90 seconds
Full regulatory compliance — aligned to CBAM (Emissions & Verification) Regulations 2026
Import Parameters
Monitoring Period (Reg. 9)
Reg. 9(2): imports before 1 Jan 2028 may use either basis. From 1 Jan 2028, Reg. 9(3) applies.
Production-year basis requires supporting evidence of production date (Reg. 16(1)(c))
Cement — Clinker Content Functional Unit
UK CBAM applies the emission factor to tonnes of clinker content, not total product weight. For blended cements, multiply import volume by the clinker fraction before using this figure. Portland cement ≈ 95% clinker; blended cements vary.
Fertiliser — Nitrogen Content Functional Unit
UK CBAM applies the emission factor to tonnes of nitrogen content, not total product weight. Multiply import volume by the nitrogen fraction of the specific product before using this figure (e.g. urea ≈ 46% N; ammonium nitrate ≈ 35% N).
Default Is a Blended Planning Estimate — Route Matters
This figure blends across production routes and origins. Confirmed EAF (electric arc furnace) production typically verifies well below this — published EAF-route data commonly falls in the 0.3–0.5 tCO₂e/t range. Confirmed BF-BOF (blast furnace–basic oxygen furnace) production typically verifies at or above it — real third-party EPD data has shown BF-BOF wire at ~2.49 tCO₂e/t, and a single higher-emission origin's own default can run considerably higher again. Know your supplier's actual route before assuming which way verification moves your number.
Reg. 8 — GWP Conversion Required
For actual emissions data, apply statutory GWP factors before reporting.
PRECURSOR GOODS — System Boundaries v1.00 (Reg. 7)
Precursor emissions must be added at Step 5 of the Reg. 5 calculation.
Commodity Type (Schedule 16 FA 2026)
Importing iron goods not listed here? — emission factors vary by product and production route.
Confirm Your Exact CN Code — optional, Annex A
This confirms whether your specific product is in scope under Schedule 16 FA 2026 — it does not change the emission factor used above, since HMRC has not published code-specific default values. Source: Annex A commodity code list.
Import Volume (Metric Tonnes)
= 10,000,000 kg (net of packing)
Quick:
Export Country
Place of Origin — Country of Production (Reg. 5)
Per customs rules of origin (TCTA 2018 ss.17(1)-(6)). May differ from export country.
⏱ Reference ETS prices as at Q2 2026. Source: ICAP Carbon Action. Actual CPR requires verified evidence of the price paid by your specific supplier — free allocation reduces effective CPR to zero in several origins shown below.
Emissions Data Type (Reg. 6(1)(c)-(e))
Actual Emission Intensity (tCO₂/tonne)
Leave blank to use sector default
Carbon Price Relief (CPR)
CPR requires GACI-accredited verification (standards confirmed 16 July 2026: ISO/IEC 17029, 14064-3, 14065, 14066) · 6-year record retention
Net Zero Commercial Analysis
SEPARATE from CBAM compliance — voluntary credits do NOT reduce CBAM liability
CCUS Tier
CBAM Compliance Liability
Gross CBAM Levy
£0
0 tCO₂ × £55/t
Full liability without CPR
Carbon Price Relief (CPR)
£0
Net Payable to HMRC
£0
Gross − CPR = Net
CY2027 Return · Due 31 May 2028
CPR at risk: £0 — documentation required
This deduction is only claimable with verified carbon pricing data from your supplier.
Without them, you pay the full gross levy.
Verified Facility Data Service — £1,500 fixed fee
We contact your suppliers, collect GACI-verified pricing data, and produce your audit-ready evidence pack.
Rate Sensitivity — two levers, not one
HMRC publishes the official UK CBAM rate quarterly from Q1 2027. See what's outside your control, and what your own data changes.
Lever 1 · outside your control
HMRC's eventual rate
£45£55/tCO₂£65
Lever 2 · within your control
Emissions data status
This Range Models Price Volatility Only — Not the Full Rate Formula
The £45–£65 range reflects short-term UK ETS auction price movement only. The actual UK CBAM rate is calculated as: auction price × (1 − BFAP × reduction factor). The reduction factor is a single, already-legislated schedule applying uniformly across all sectors — confirmed at 97.5% for 2027, easing to 95% (2028), 90% (2029), 77.5% (2030), down to 0% by 2035. The BFAP — each sector's own historical share of emissions covered by free allocation — is the piece HMRC hasn't published yet, and it varies by sector. Once BFAP is confirmed, the real rate for any sector shown here could sit well below this range's floor — and is expected to rise in later years as the reduction factor itself declines. (This UK-side mechanism is separate from the EU producer free-allocation figures referenced elsewhere on this page for Carbon Price Relief — different jurisdiction, different question, similar-looking numbers by coincidence.)
Net payable, this combination
£0
Rate uncertainty alone
±£0
resolves when HMRC publishes — nothing to action
Verification alone
£0
holding rate constant — this is what we fix
Verified figures shown here are illustrative — the actual saving depends entirely on your specific supplier's measured intensity. For origins where a real carbon price is paid, verification is also the gate Carbon Price Relief sits behind: CPR cannot be claimed without GACI-accredited verification.
0%
CPR
Levy Breakdown
■ Carbon Price Relief■ Net Payable
Net Zero Commercial Analysis — NOT a CBAM Deduction
Voluntary carbon credits do NOT reduce CBAM liability. Separate commercial analysis only.
CCUS Investment
£0
Green Premium Recovery
£0
Est. 15% premium on Net Zero supply
Net Commercial Benefit
£0
Calculation Detail
Please accept the declaration of accuracy to continue
Personal follow-up within 24 hours · Fixed fee £2,500
CBAM Proof™ by Archimedes Lever Ltd (Co. 16859569). Estimates only — not tax advice. Consult a qualified adviser before filing HMRC declarations.
Planning rate £55/tCO₂ is the current UK ETS price used as a proxy — HMRC will publish sector-specific quarterly CBAM rates from Q1 2027; actual liability determined at that point. This proxy reflects UK ETS price levels only — it does not yet reflect the free-allocation adjustment built into the real rate formula: auction price × (1 − BFAP × reduction factor). The reduction factor is a single schedule confirmed in law across all sectors (97.5% in 2027, easing to 95% in 2028, 90% in 2029, 77.5% in 2030, 0% by 2035); the Baseline Free Allocation Percentage (BFAP) is the sector-specific piece HMRC hasn't published yet. The real published rate could sit well below £55 once BFAP is confirmed for each sector, and is expected to rise in later years as the reduction factor declines. Note: under Regulation 9, you may use either the import year or the production year as your monitoring period for goods imported before 1 January 2028 — so verified data from an already-completed prior year (e.g. 2025 or 2026 production) can be used now, and supplier engagement for verified emissions data should begin immediately rather than waiting for any period to close. HMRC has confirmed the full verifier accreditation standards (16 July 2026): GACI full membership, GACI Multilateral Recognition Agreement signatory, and accreditation to ISO/IEC 17029:2019, ISO 14064-3:2019, ISO 14065:2020 and ISO 14066:2023 — this confirms the qualifying criteria, not a named list of individually approved verifiers.
Default emission values shown here are illustrative planning estimates, not confirmed HMRC figures — HMRC has not yet published UK-specific default values, and the draft System Boundaries Document itself confirms these remain unpublished. Steel, cement and aluminium figures are informed by the same category of data HMRC has said its own defaults will draw on — country-level averages used within EU CBAM, per Implementing Regulation (EU) 2025/2621 — cross-checked against independently published production data and, for steel, a real third-party Environmental Product Declaration. UK CBAM covers direct (Scope 1) production emissions only from 1 January 2027 — indirect emissions such as purchased electricity are excluded until 2029 at the earliest; the aluminium figure has been set on a direct-only basis to reflect this. Cement calculations apply EF to total import weight — actual liability uses clinker content as the functional unit; fertiliser calculations use total product weight — actual liability uses nitrogen content. Carbon prices sourced from ICAP Carbon Action (Q2 2026).
Voluntary carbon credits cannot reduce CBAM liability — Net Zero analysis shown separately for commercial planning only. Registration triggers on a rolling basis (£50,000 trailing-12-month test checked monthly, or 30-day forward test) and is normally due within 30 days of the trigger; HMRC's first-year easement extends this to 31 January 2028 for 2027 triggers. The first accounting period is annual (2027) with return and payment due 31 May 2028, then quarterly from 2028 — per HMRC's April 2026 policy summary; final regulations pending.
Next Step
Get the data that moves this number
HMRC's default emission factor assumes the worst-case producer. Your actual mill may perform better — but you need supplier data to evidence that for your verifier.
Free · 60 seconds · Built against Regulations 5 and 9–16
CBAM Proof™ — Supplier Data Request Generator
Step 1 of 5 — Confirm your calculator context
Pre-populated from your calculator. Edit if needed.
EMISSIONS DATA TYPE
These details will appear in the generated letter header.
Note: this letter collects supplier data — independent GACI-accredited verification is still required before figures are used on a return.
Your supplier data request is ready
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CBAM Compliance Services & Pricing
Start free with the calculator. When you need a board-ready number, choose the audit, data service, or ongoing retainer below.
Exposure Check
Free
Instant CBAM liability estimate across Conservative, Central and Stressed scenarios
CBAM liability calculator
5 commodity types covered
10+ source countries
Carbon Price Relief estimate
HMRC guidance links
Time-Critical
Verified Facility Data Service
£1,500 fixed fee
Verified mill data, GACI-aligned — the evidence base that replaces HMRC's worst-case default
Direct supplier engagement — production route, emissions intensity, precursor data
Annual return preparation session, ahead of the 31 May deadline
6-year record retention
Carbon price alerts
GACI verification coordination
Priority support
FAQ
Common questions
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Readiness Audit — £2,500
I confirm the information provided is accurate to the best of my knowledge and is submitted for compliance planning purposes only. I understand this is an estimate and not a binding HMRC determination.