SG3 postcode district: Knebworth and around, Hertfordshire

SG3 is a postcode district in Hertfordshire, with 206 postcodes in use in 1 sector. It has postcodes in Knebworth and Woolmer Green. It is split between 3 councils: North Hertfordshire (119 postcodes), Welwyn Hatfield (49) and East Hertfordshire (38).

Postcodes in use
206
Sectors
1
Councils
3 councils
Places
2 places

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

Every postcode in SG3, and which are new since 2020

Map of every postcode in SG3, by new since 2020 Of the 206 postcodes in SG3 that ONS places, 17 are new since 2020 and 189 were in use before 2020. One group of new postcodes is outlined: 10 new postcodes since 2020. 2 postcodes lie beyond the edge and are listed under the map. Places named: Knebworth, Woolmer Green. Drawn over roads, rivers and built-up areas. North is up; the scale bar is 1 km. A1(M)A602 SG3 6AA: before 2020SG3 6AB: before 2020SG3 6AD: before 2020SG3 6AE: before 2020SG3 6AF: before 2020SG3 6AG: before 2020SG3 6AH: before 2020SG3 6AJ: before 2020SG3 6AL: before 2020SG3 6AN: before 2020SG3 6AP: before 2020SG3 6AQ: before 2020SG3 6AR: before 2020SG3 6AS: before 2020SG3 6AT: before 2020SG3 6AU: before 2020SG3 6AW: before 2020SG3 6AX: before 2020SG3 6AY: before 2020SG3 6AZ: before 2020SG3 6BA: before 2020SG3 6BB: before 2020SG3 6BD: before 2020SG3 6BE: before 2020SG3 6BG: before 2020SG3 6BH: before 2020SG3 6BJ: before 2020SG3 6BL: before 2020SG3 6BN: before 2020SG3 6BP: before 2020SG3 6BQ: before 2020SG3 6BS: before 2020SG3 6BT: before 2020SG3 6BU: before 2020SG3 6BW: before 2020SG3 6BX: before 2020SG3 6BY: before 2020SG3 6DA: before 2020SG3 6DB: before 2020SG3 6DD: before 2020SG3 6DE: before 2020SG3 6DF: before 2020SG3 6DG: before 2020SG3 6DH: before 2020SG3 6DJ: before 2020SG3 6DN: before 2020SG3 6DP: before 2020SG3 6DQ: before 2020SG3 6DR: before 2020SG3 6DS: before 2020SG3 6DT: before 2020SG3 6DU: before 2020SG3 6DX: before 2020SG3 6DZ: before 2020SG3 6EA: before 2020SG3 6EB: before 2020SG3 6ED: before 2020SG3 6EE: before 2020SG3 6EH: before 2020SG3 6EL: before 2020SG3 6EN: before 2020SG3 6EQ: before 2020SG3 6ER: before 2020SG3 6EX: before 2020SG3 6EY: before 2020SG3 6FD: before 2020SG3 6GL: before 2020SG3 6HB: before 2020SG3 6HE: before 2020SG3 6HF: before 2020SG3 6HG: before 2020SG3 6HH: before 2020SG3 6HJ: before 2020SG3 6HP: before 2020SG3 6HS: before 2020SG3 6HW: before 2020SG3 6HY: before 2020SG3 6JD: before 2020SG3 6JE: before 2020SG3 6JF: before 2020SG3 6JG: before 2020SG3 6JJ: before 2020SG3 6JL: before 2020SG3 6JN: before 2020SG3 6JP: before 2020SG3 6JS: before 2020SG3 6JU: before 2020SG3 6JW: before 2020SG3 6JX: before 2020SG3 6JY: before 2020SG3 6JZ: before 2020SG3 6LA: before 2020SG3 6LB: before 2020SG3 6LD: before 2020SG3 6LE: before 2020SG3 6LG: before 2020SG3 6LJ: before 2020SG3 6LL: before 2020SG3 6LN: before 2020SG3 6LP: before 2020SG3 6LR: before 2020SG3 6LS: before 2020SG3 6LT: before 2020SG3 6LU: before 2020SG3 6LW: before 2020SG3 6LX: before 2020SG3 6LZ: before 2020SG3 6NA: before 2020SG3 6NB: before 2020SG3 6ND: before 2020SG3 6NL: before 2020SG3 6NN: before 2020SG3 6NP: before 2020SG3 6NS: before 2020SG3 6NU: before 2020SG3 6NX: before 2020SG3 6PB: before 2020SG3 6PD: before 2020SG3 6PE: before 2020SG3 6PF: before 2020SG3 6PG: before 2020SG3 6PH: before 2020SG3 6PL: before 2020SG3 6PP: before 2020SG3 6PR: before 2020SG3 6PS: before 2020SG3 6PT: before 2020SG3 6PU: before 2020SG3 6PW: before 2020SG3 6PY: before 2020SG3 6QA: before 2020SG3 6QB: before 2020SG3 6QD: before 2020SG3 6QE: before 2020SG3 6QF: before 2020SG3 6QG: before 2020SG3 6QH: before 2020SG3 6QJ: before 2020SG3 6QL: before 2020SG3 6QN: before 2020SG3 6QT: before 2020SG3 6QX: before 2020SG3 6QZ: before 2020SG3 6RA: before 2020SG3 6RB: before 2020SG3 6RD: before 2020SG3 6RE: before 2020SG3 6RF: before 2020SG3 6RG: before 2020SG3 6RH: before 2020SG3 6RJ: before 2020SG3 6RL: before 2020SG3 6RN: before 2020SG3 6RP: before 2020SG3 6RR: before 2020SG3 6RS: before 2020SG3 6RU: before 2020SG3 6RX: before 2020SG3 6RZ: before 2020SG3 6SA: before 2020SG3 6SB: before 2020SG3 6SE: before 2020SG3 6SG: before 2020SG3 6SL: before 2020SG3 6SP: before 2020SG3 6SR: before 2020SG3 6SS: before 2020SG3 6ST: before 2020SG3 6SU: before 2020SG3 6SX: before 2020SG3 6SZ: before 2020SG3 6TA: before 2020SG3 6TB: before 2020SG3 6TD: before 2020SG3 6TE: before 2020SG3 6TF: before 2020SG3 6TG: before 2020SG3 6TL: before 2020SG3 6TN: before 2020SG3 6TP: before 2020SG3 6TQ: before 2020SG3 6EU: new since 2020SG3 6EW: new since 2020SG3 6FA: new since 2020SG3 6FB: new since 2020SG3 6FE: new since 2020SG3 6FF: new since 2020SG3 6FG: new since 2020SG3 6FH: new since 2020SG3 6FN: new since 2020SG3 6FP: new since 2020SG3 6FS: new since 2020SG3 6HL: new since 2020SG3 6FQ: new since 2020SG3 6YY: new since 2020 KnebworthWoolmer Green 10 new postcodes since 2020, outlined: this goes to SG3 6FL, the newest of them10 new postcodes since 2020 Map of every postcode in SG3, by new since 2020 Of the 206 postcodes in SG3 that ONS places, 17 are new since 2020 and 189 were in use before 2020. One group of new postcodes is outlined: 10 new postcodes since 2020. 2 postcodes lie beyond the edge and are listed under the map. Places named: Knebworth, Woolmer Green. Drawn over roads, rivers and built-up areas. North is up; the scale bar is 1 km. A1(M) KnebworthWoolmer Green 10 new postcodes since 2020, outlined: this goes to SG3 6FL, the newest of them10 new postcodes since 2020
  • New since 2020: 17
  • In use before 2020: 189
  • Outline: where 5 or more new postcodes since 2020 lie together

Of the 206 postcodes in SG3 that ONS places, 17 are new since 2020 and 189 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 180 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 51.8603, longitude -0.1825. 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

SG3 6FSOctober 2025SG3 6FRSeptember 2024SG3 6YYMay 2023SG3 6FLApril 2022SG3 6FNApril 2022

2 further out, not drawn

These postcodes lie well apart from the rest, so the map is drawn without them to show the rest closer; they are in every count.

SG3 6FRSG3 6PX

Where the new postcodes lie together

  • 10 new postcodes since 2020, outlined on the map. SG3 6FL, is the newest of them.

What broadband can you get in SG3?

Ofcom reports on 203 of the 206 postcodes in SG3. At 142 of them every home and business can get gigabit broadband.

Postcodes where every home can get gigabit142 of 203
Postcodes where every home can get superfast190 of 203

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 SG3 at risk of flooding?

None of the 206 postcodes in SG3 is on the Environment Agency's list of postcodes with a home or business in an area at risk of flooding from rivers or the sea.

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 SG3?

Homes in SG3 sold for a typical £452,000 in the 12 months to August 2026, across 95 sales, down 6.8% on the 12 months before, HM Land Registry's figures show.

£452,000 typical price, the 12 months to August 2026
£485,000 12 months to August 2025
▼ down 6.8% on the 12 months before
  • Detached £750,000 19 sales
  • Semi-detached £507,500 24 sales
  • Terraced £400,000 30 sales
  • Flat or maisonette £263,500 22 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

Postcodes in SG3

Pick a sector, then a postcode. A sector is the district plus the next digit.

SG3 6206 postcodes
UK postcode format explained

Places in SG3

Towns and villages with postcodes in SG3, and how many each has here.

Knebworth postcodes,98Woolmer Green postcodes,48

Who covers SG3

How many of the district's postcodes in use fall under each council, constituency and police force area.

Councils

What council am I in?

Constituencies

  • Stevenage156
  • Welwyn Hatfield49
  • North East Hertfordshire1

Police force areas

  • Hertfordshire206

Next to SG3

SG2 postcode district SG4 postcode district All SG districts Knebworth postcodes

"Next to" is by number: the districts before and after SG3 in the SG area.

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