SG1 postcode district: Stevenage and around, Hertfordshire

SG1 is a postcode district in Hertfordshire, with 1,284 postcodes in use in 7 sectors. It has postcodes in Stevenage. It is split between 2 councils: Stevenage (1,216 postcodes) and North Hertfordshire (68).

Postcodes in use: 1,284
Sectors: 7
Councils: 2 councils
Places: Stevenage

Source: Office for National Statistics (ONS) Postcode Directory, August 2026, loaded 20 October 2026. See all our data sources

Every postcode in SG1, and which are new since 2020

New since 2020: 96
In use before 2020: 1,188
Outline: where 5 or more new postcodes since 2020 lie together

Of the 1,284 postcodes in SG1 that ONS places, 96 are new since 2020 and 1,188 were in use before 2020.

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. New since 2020 means it came into use in January 2020 or later. A dashed outline shows where 5 or more lie within 150 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 51.9133, longitude -0.1956. Open this area on OpenStreetMap

Source: Office for National Statistics (ONS) Postcode Directory, August 2026, loaded 20 October 2026, the centre point of each postcode; when each came into use: the same directory; roads, rivers and built-up areas: 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. How we use them

The 5 newest postcodes

SG1 4YWJuly 2026 SG1 4YXJuly 2026 SG1 4ZAJuly 2026 SG1 4ZEJuly 2026 SG1 9TAJuly 2026

Where the new postcodes lie together

29 new postcodes since 2020, outlined on the map. SG1 4YX, is the newest of them.
27 new postcodes since 2020, outlined on the map. SG1 9TA, is the newest of them.
13 new postcodes since 2020, outlined on the map. SG1 2ZF, is the newest of them.
6 new postcodes since 2020, outlined on the map. SG1 1FU, is the newest of them.

What broadband can you get in SG1?

Ofcom reports on 1,185 of the 1,284 postcodes in SG1. At 898 of them every home and business can get gigabit broadband.

Postcodes where every home can get gigabit898 of 1,185

Postcodes where every home can get superfast1,133 of 1,185

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 checker

Source: Ofcom, Connected Nations, Spring 2026, data for January 2026, Open Government Licence v3.0. How we use it

Is SG1 at risk of flooding?

19 of the 1,284 postcodes in SG1 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 2 homes and businesses in an area at high or medium risk.

Homes and businesses in an area at risk, at 19 of 1,284 postcodes Medium: 2Low: 284Very low: 6

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, Risk of Flooding from Rivers and Sea (postcodes in areas at risk), published 6 July 2026, Open Government Licence v3.0. How we use it

What do homes sell for in SG1?

Homes in SG1 sold for a typical £350,000 in the 12 months to August 2026, across 460 sales, up 0.6% on the 12 months before, HM Land Registry's figures show.

£350,000 typical price, the 12 months to August 2026

£347,750 12 months to August 2025

▲ up 0.6% on the 12 months before

Detached £600,000 59 sales
Semi-detached £425,000 88 sales
Terraced £340,000 216 sales
Flat or maisonette £207,200 97 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 September 2026. Contains HM Land Registry data © Crown copyright and database right 2021. This data is licensed under the Open Government Licence v3.0. How we use it