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 CM3. 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
CM3 1AA	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
CM3 1AB	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
CM3 1AD	Chelmsford	Strong broadband coverage Gigabit availability is 91.7%, with 91.7% 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
CM3 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
CM3 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
CM3 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
CM3 1AH	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
CM3 1AJ	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
CM3 1AL	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
CM3 1AN	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
CM3 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
CM3 1AQ	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
CM3 1AR	Chelmsford	Strong broadband coverage Gigabit availability is 88.9%, with 88.9% 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
CM3 1AS	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
CM3 1AT	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
CM3 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
CM3 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
CM3 1AX	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
CM3 1AY	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
CM3 1AZ	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
CM3 1BA	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
CM3 1BD	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
CM3 1BE	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
CM3 1BG	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
CM3 1BJ	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

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.