CM1 postcode district: Chelmsford and around, Essex
CM1 is a postcode district in Essex, with 1,561 postcodes in use in 7 sectors. It has postcodes in Chelmsford, Writtle, Broomfield and 1 more place. It is split between 2 councils: Chelmsford (1,535 postcodes) and Uttlesford (26).
- Postcodes in use
- 1,561
- Sectors
- 7
- Councils
- 2 councils
- Places
- 4 places
Source: ONS Postcode Directory, August 2026, loaded 20 October 2026.
Every postcode in CM1, by gigabit broadband
- No home or business can get gigabit: 71
- Some can get gigabit: 183
- Every home and business can get gigabit: 1,195
- Ofcom gives no figure: 112
- Outline: where 5 or more postcodes without gigabit lie together
Of the 1,561 postcodes in CM1 that ONS places, 71 have no home or business that can get gigabit, 183 have some that can, 1,195 can all get it and 112 have no Ofcom figure.
Each mark is a postcode's centre point as ONS gives it, not a building. Press one to see its postcode and open its page. A dashed outline shows where 5 or more lie within 160 metres of each other. It is not a boundary, and no boundary is drawn. Where marks overlap, the one first in the key is drawn; the counts include every postcode.
The middle of its postcodes: latitude 51.7475, longitude 0.4583. Open this area on OpenStreetMap
Sources: ONS Postcode Directory, August 2026, loaded 20 October 2026; Ofcom Connected Nations, Connected Nations, Spring 2026; roads, rivers and built-up areas: Ordnance Survey open maps. Contains OS data © Crown copyright and database right 2026. Drawn by us. Street map: Ordnance Survey, OS Open Zoomstack, Open Government Licence v3.0, drawn with MapLibre.
Postcodes without gigabit
71 postcodes here have no gigabit. These are the 12 first in postcode order.
Where the postcodes without gigabit lie together
What broadband can you get in CM1?
Ofcom reports on 1,449 of the 1,561 postcodes in CM1. At 1,195 of them every home and business can get gigabit broadband, and at 4 some cannot get decent broadband (10 Mbit/s).
Ofcom gives each postcode's share of homes and businesses, not how many there are, so these count postcodes. Each postcode page has its own figures. A provider's checker answers for one address.
Check one address on Ofcom's checkerSource: Ofcom Connected Nations, Connected Nations, Spring 2026, data for January 2026.
Is CM1 at risk of flooding?
86 of the 1,561 postcodes in CM1 have a home or business in an area at risk of flooding from rivers or the sea, the Environment Agency says. At those, it puts 314 homes and businesses in an area at high or medium risk.
High: 3.3% or more a year (1 in 30). Medium: 1% to 3.3% a year. Low: 0.1% to 1% a year. Very low: under 0.1% a year (1 in 1,000). Each band is the chance of flooding in any one year.
Homes and businesses in an area at risk of flooding from rivers or the sea, as the Environment Agency counts them, added up over the postcodes. It is for the land, not each building, and leaves out surface water, groundwater and sewers. Each postcode page has its own figures and its flood warning areas.
Source: Environment Agency flood risk, published 6 July 2026.
What do homes sell for in CM1?
Homes in CM1 sold for a typical £396,000 in the 12 months to September 2026, across 737 sales, HM Land Registry's figures show. The 12 months before gave £405,000 from 1,106 sales: not a change larger than chance would explain, given which homes happened to sell.
- Detached £605,000 172 sales
- Semi-detached £432,500 228 sales
- Terraced £360,000 160 sales
- Flat or maisonette £220,000 177 sales
Each bar is that kind's typical price, against the most expensive kind here.
Standard sales of homes at market value. A typical price is the median, the middle sale. Sales take weeks to be registered, so the last month or two are incomplete. Each postcode page gives the figure for its own postcode sector.
Source: HM Land Registry Price Paid Data, files dated 28 October 2026.
Postcodes in CM1
Pick a sector, then a postcode. A sector is the district plus the next digit.
Places in CM1
Towns and villages with postcodes in CM1, and how many each has here.
Who covers CM1
How many of the district's postcodes in use fall under each council, constituency and police force area.
Councils
- Chelmsford1,535
- Uttlesford26
Constituencies
- Chelmsford1,080
- North West Essex480
- Maldon1
Police force areas
- Essex1,561
Next to CM1
"Next to" is by number: the districts before and after CM1 in the CM area.
Check a postcode
Where the facts on this page come from
- Office for National Statistics: ONS Postcode Directory
- Ofcom Connected Nations
- Environment Agency flood risk
- HM Land Registry Price Paid Data
Contains public sector information licensed under the Open Government Licence v3.0. Contains HM Land Registry data © Crown copyright and database right 2021. This data is licensed under the Open Government Licence v3.0.
Licence: Open Government Licence v3.0.
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