Detached
£486,616
41% above the Old St. Mellons average
34.0% of sales
What is the average house price in Old St. Mellons? £344,566
The average house price in Old St. Mellons is £344,566, based on 101 homes sold in the 12 months to September 2026. Prices are up 11.1% (£34,370) on a year earlier.
- 1 year change
- +11.1%
- Sold in 12 months
- 101
- Data up to
- September 2026
Sold prices from HM Land Registry, not asking prices. How we calculate this
How much does each type of property cost in Old St. Mellons?
Average sold price by property type, and each type's share of recent sales.
Semi-detached
£281,202
18% below the Old St. Mellons average
36.5% of sales
Terraced
£253,079
27% below the Old St. Mellons average
22.3% of sales
Flats
£174,250
49% below the Old St. Mellons average
7.1% of sales
Are house prices in Old St. Mellons going up or down?
House prices in Old St. Mellons are rising: up 11.1% (£34,370) over the past year. Over the past 10 years, prices are up 12.6% (£38,683).
Past 12 months
+11.1%
+£34,370From £310,196 to £344,566
£344,566£309,921
Past 10 years
+12.6%
+£38,683From £305,883 to £344,566
£344,566£248,005
Quick answers for Old St. Mellons
11 key facts at a glance.
When did prices peak?
£714,333
Highest average, reached in May 2026
How many homes sold?
101
Recorded so far for the 12 months to September 2026
What sells most often?
Semi-detached houses
36.5% of recent sales
What is the most common price range?
£200k - £300k
45.4% of sales
How many people live in Old St. Mellons?
4,701
3,478 people per square mile · Very High (Census 2021)
Population density is Very High, on a scale from Very Low to Very High.
Usual residents, including communal establishments.
How many households are in Old St. Mellons?
2,071
1,532 households per square mile · Very High (Census 2021)
Household density is Very High, on a scale from Very Low to Very High.
Occupied households, not communal establishments.
How much green space is in Old St. Mellons?
32 m² per resident
More green space per resident than 52% of areas in England and Wales. That's about 4.4 football pitches for every 1,000 residents.
4.2% of the area · 2 public parks. Parks, playing fields, allotments and other public green space, not counting golf courses. Contains OS data © Crown copyright and database right 2026.
What is the crime rate in Old St. Mellons?
67 crimes per 1,000 residents
High · −25.1% on the previous year · 12 months to September 2026
Crime rate is High, on a scale from Very Low to Very High.
Contains public sector information licensed under the Open Government Licence v3.0. Source: police.uk.
How many listed buildings are in Old St. Mellons?
18 listed buildings
Fewer listed buildings per home than 63% of areas in England and Wales.
1 Grade I · 1 scheduled monument · Source: Cadw
What's the air quality in Old St. Mellons?
NO₂ 11.5 µg/m³
Very High for England and Wales · PM2.5 7.9 µg/m³ (High) · 2025 annual average
NO₂ level is Very High, on a scale from Very Low to Very High.
Background levels where residents live, not beside busy roads. Contains public sector information licensed under the Open Government Licence v3.0. Source: Defra modelled background pollution, 2025.
How does Old St. Mellons rank?
14th most expensive area of Cardiff.
Compared with 36 areas with sales in the last 12 months
What are the most expensive homes sold in Old St. Mellons?
The highest recorded sale prices in Old St. Mellons, from HM Land Registry.
#1 Most expensive sale
maesycrochan house druidstone road, cardiff
£1,611,250
Sold June 2021
View house details
How do house prices in Old St. Mellons compare with nearby areas?
Old St. Mellons compared with the 6 nearest other areas in Cardiff.
Old St. Mellons vs Pontprennau
- Old St. Mellons
- £344,566
- Pontprennau
- £310,085−£34,481
Open comparison
Old St. Mellons vs Llanrumney
- Old St. Mellons
- £344,566
- Llanrumney
- £227,313−£117,253
Open comparison
Old St. Mellons vs Pentwyn
- Old St. Mellons
- £344,566
- Pentwyn
- £233,191−£111,375
Open comparison
Old St. Mellons vs Rumney
- Old St. Mellons
- £344,566
- Rumney
- £243,790−£100,776
Open comparison
Old St. Mellons vs Trowbridge
- Old St. Mellons
- £344,566
- Trowbridge
- £245,463−£99,103
Open comparison
Old St. Mellons vs Llanedeyrn
- Old St. Mellons
- £344,566
- Llanedeyrn
- £180,164−£164,402
Open comparison
Thinking of buying in Old St. Mellons?
There's a lot to think about. Whether it's a home to live in or a buy-to-let, our free checklist walks you through what to check before you make an offer.
What to check before you buyWhere does this data come from?
Price information is from HM Land Registry, location boundaries are from OpenStreetMap, and households and population are from Nomis Census 2021 postcode estimates (21 March 2021). Parks and green space are from OS Open Greenspace. Contains OS data © Crown copyright and database right 2026. Crime is from police.uk street-level data. Contains public sector information licensed under the Open Government Licence v3.0. Source: police.uk. Listed buildings and scheduled monuments are from Historic England and Cadw, and conservation areas from planning.data.gov.uk. Designated Historic Asset GIS Data, The Welsh Historic Environment Service (Cadw), licensed under the Open Government Licence. Air quality is from Defra modelled background pollution maps. Contains public sector information licensed under the Open Government Licence v3.0. Source: Defra modelled background pollution, 2025.
Last updated 11 November 2026 at 01:33 with the latest Land Registry data (September 2026). The Old St. Mellons dataset covers 134 postcodes.
Contains HM Land Registry data © Crown copyright and database right 2026. This data is licensed under the Open Government Licence v3.0.
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