Broadband and mobile checker

Search a postcode or postcode area against the current live broadband and mobile coverage seams.

Source: Ofcom broadband and mobile coverage. Coverage: Live connectivity rows matched postcode area CM1. Broadband is postcode level and mobile coverage remains area-level only in the current public seam.. Freshness: Broadband year 2024 · Mobile year 2025. Matches: 25.
Postcode Area Broadband Mobile Freshness
CM1 1AE Chelmsford Strong broadband coverage
Gigabit availability is 100%, with 100% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1AF Chelmsford Strong broadband coverage
Gigabit availability is 100%, with 100% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1AG Chelmsford Strong broadband coverage
Gigabit availability is 100%, with 100% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1AH Chelmsford Broadband coverage is mixed
Gigabit availability is 33.3%, with 33.3% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1AN Chelmsford Strong broadband coverage
Gigabit availability is 80%, with 80% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1AP Chelmsford Strong broadband coverage
Gigabit availability is 100%, with 100% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1AQ Chelmsford Strong broadband coverage
Gigabit availability is 100%, with 100% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1AT Chelmsford Partial connectivity coverage
No current broadband summary row matched this postcode.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Mobile year 2025
CM1 1AU Chelmsford Strong broadband coverage
Gigabit availability is 100%, with 100% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1AW Chelmsford Broadband coverage is mixed
Gigabit availability is 0%, with 0% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1BA Chelmsford Partial connectivity coverage
No current broadband summary row matched this postcode.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Mobile year 2025
CM1 1BB Chelmsford Partial connectivity coverage
No current broadband summary row matched this postcode.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Mobile year 2025
CM1 1BD Chelmsford Broadband coverage is mixed
Gigabit availability is 50%, with 50% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1BE Chelmsford Strong broadband coverage
Gigabit availability is 82.6%, with 82.6% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1BS Chelmsford Strong broadband coverage
Gigabit availability is 100%, with 100% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1BT Chelmsford Broadband coverage is mixed
Gigabit availability is 0%, with 0% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1BY Chelmsford Strong broadband coverage
Gigabit availability is 100%, with 100% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1DB Chelmsford Strong broadband coverage
Gigabit availability is 100%, with 100% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1DD Chelmsford Broadband coverage is mixed
Gigabit availability is 0%, with 0% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1DE Chelmsford Broadband coverage is mixed
Gigabit availability is 50%, with 50% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1DG Chelmsford Broadband coverage is mixed
Gigabit availability is 0%, with 0% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1DH Chelmsford Strong broadband coverage
Gigabit availability is 100%, with 100% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1DL Chelmsford Strong broadband coverage
Gigabit availability is 100%, with 100% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1DN Chelmsford Strong broadband coverage
Gigabit availability is 94.7%, with 94.7% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025
CM1 1DR Chelmsford Strong broadband coverage
Gigabit availability is 98.9%, with 98.9% of premises at at least 300 Mbps and 0% below the Universal Service Obligation.
 4G 100% · 5G 51.1%
4G strong-coverage share is 100%, with 5G at 51.1% in the current area-level summary.
 Broadband year 2024 · Mobile year 2025

Known caveats

  • Mobile coverage is still served at area level in the public seam, so treat it as a shortlist signal rather than a street-level verdict.
  • Connectivity rows do not replace a final provider and address-level availability check before you commit to a property.
  • If you search a postcode area, neighbouring postcode rows can differ enough that the exact postcode follow-up still matters.