What does a SO16 postcode tell you?

That the address lies in the SO16 district of the SO (Southampton) postcode area, which the directory places around South East. The inward half of the full postcode narrows it to a street or a building; the district alone does not, and an address written with a district and no inward half cannot be checked against the register.

Does a street listed here mean an address on it exists?

It means OS Open Names lists a road of that name under the district, which is what the address lookup answers as a street-level match. It says nothing about any building on it: Great Britain publishes no open register of buildings, so the lookup answers exists: null there and confirms the street alone.

Who lives at these postcodes?

Nobody on this page. A postcode directory says whether a code is in use, never who is there, and a streets register lists roads, not occupants. The address lookup carries no field about a person and never will.

SO16 postcode district

What the public directories installed here say about the SO16 postcode district: how many of its postcodes are in use, the places OS Open Names lists for them, the streets it files under the district and the district's centroid. Counted from the national postcode directory and OS Open Names on 2026-09-18, and never about who is at an address.

postcode area	SO (Southampton)
live postcodes	1,542
terminated postcodes	346
streets listed	661
centroid	50.93675, -1.43352
counted on	2026-09-18

Places the directory lists for SO16

OS Open Names places the district's postcodes in these settlements, boroughs, counties and regions, most often first. A town written as any of them matches the directory in an address lookup, and one written as another place in the SO area is reported but not scored.

South East
Southampton
City of Southampton
Test Valley
Hampshire
Rownhams
Nursling
Chilworth
Chilworth Old Village

Postcodes in use

1,542 postcodes in SO16 were in use on the day of the count. A postcode directory says whether a code is in use, never who is there. 346 of its 1,888 postcodes have been terminated: a real address written with one has moved on, which is not the same thing as a typo, and the address lookup scores it rather than refusing it.

Centroid: 50.93675, -1.43352 — the mean of the live postcodes' centroids, which locates the district, not any building in it.

Streets filed under SO16

OS Open Names files 661 roads under SO16. A road is filed under one district even where it runs through several, so a street missing here may be listed under a neighbouring district — which is why the address lookup never calls a British street absent.

A35
A3057
Abbotsfield Close
Abercrombie Gardens
Abingdon Gardens
Acorn Drive
Adanac Drive
Aldermoor Avenue
Aldermoor Close
Aldermoor Road
Alderney Close
Alder Road
Alice Mews
All Saints Close
Anderby Road
Anderdon Avenue
Andes Road
Andromeda Road
Arcadia Close
Ardnave Crescent

the first 20 of 661, alphabetically

Check an address in SO16

The address checker opens on Great Britain with the district in the field: add the street, the number and the full postcode, and it answers the postcode's status, whether the street is filed under the district, and what kind of delivery point the address names.

Check an address in SO16

curl https://spaw.co/api/v1/address \
  -H "Authorization: Bearer sk_live_…" \
  -H "Content-Type: application/json" \
  -d '{"address": "10 Downing Street, London SO16 …", "country": "GB"}'

Common questions about SO16

What does a SO16 postcode tell you?: That the address lies in the SO16 district of the SO (Southampton) postcode area, which the directory places around South East. The inward half of the full postcode narrows it to a street or a building; the district alone does not, and an address written with a district and no inward half cannot be checked against the register.
Does a street listed here mean an address on it exists?: It means OS Open Names lists a road of that name under the district, which is what the address lookup answers as a street-level match. It says nothing about any building on it: Great Britain publishes no open register of buildings, so the lookup answers exists: null there and confirms the street alone.
Who lives at these postcodes?: Nobody on this page. A postcode directory says whether a code is in use, never who is there, and a streets register lists roads, not occupants. The address lookup carries no field about a person and never will.

Where the counts come from

ons-postcode-directory · version 2026-08 · Contains ONS, OS and Royal Mail data © Crown copyright and database right 2026, Open Government Licence v3.0. Northern Ireland postcodes are excluded: their reuse needs a Land & Property Services licence.

Data synced on 2026-09-18: the newest register or postcode directory copy installed here.

Other districts in SO

Wrong result, or is it about you? If this tool said something you think is wrong, tell us and a person reads it. If Spaw is holding data about you and you never signed up here — a customer may have had your address verified, or reported that a message to it bounced — erase it yourself, confirmed by mail to that address and with no account needed.

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