House prices in CF3 6 (Old St Mellons)

This article reveals price per square metre data and various charts to help you understand current housing market in Old St Mellons, St Mellons (CF3 6).

Defining 'CF3 6'

This analysis is limited to properties whose postcode starts with "CF3 6", this is also called the postcode sector. It is shown in red on the map above. There are no official names for postcode sectors so I've just labelled it Old St Mellons.

You can click on the map labels to change to a neighbouring sector, or you can enter a different postcode sector (e.g. CM23 4) below.

FYI, a postcode sector is the full postcode without the last two letters.

Price per square metre

Knowing the average house price in Old St Mellons is not much use. However, knowing average price per square metre can be quite useful. Price per sqm allows some comparison between properties of different size. We define price per square metre as the sold price divided by the internal area of a property:

£ per sqm = price ÷ internal area
E.g. 185, Mortimer Avenue, Old St Mellons, St Mellons, sold for £260,000 on Apr-2024. Given the internal area of 94 square metres, the price per sqm is £2,765.

England & Wales have been officially metric since 1965. However house price per square foot is prefered by some estate agents and those of sufficiently advanced age ;-) They may want to convert square meters on this page to square feet.

The chart below is called a histogram, it helps you see the distribution of this house price per sqm data. To make this chart we put the sales data into a series of £ per sqm 'buckets' (e.g. £3,800-£4,000, £4,000-£4,200, £4,200-£4,400 etc...) we then count the number of sales with within in each bucket and plot the results. The chart is based on 80 sales in Old St Mellons (CF3 6) that took place in the last two years.

Distribution of £ per sqm for Old St Mellons, St Mellons
Distribution of £ per sqm house prices in Old St Mellons

You can see the spread of prices above. This is because although internal area is a key factor in determining valuation, it is not the only factor. Many factors other than size affect desirability; these factors could be condition, aspect, garden size, negotiating power of the vendor etc.

The spread of prices will give you a feel of the typical range to expect in Old St Mellons (CF3 6). Of the 80 transactions, half were sold for between £3,200 and £4,010 per square metre. The median, or 'middle', price per square metre in 'CF3 6' is £3,710. Notably, only 25% of properties that sold recently were valued at more than £4,010 sqm. For anything to be valued more than this means it has to be more desireable than the clear majority of homes.

Price map for Old St Mellons, St Mellons

Do have a look at the interactive price map I created. I find it useful and I am sure it will help you in exploring St Mellons. You can zoom in all the way to individual properties and then all the way back out to see the whole country. The colours show the current estimated property values.

Property price heatmap for Old St Mellons
House price heatmap for Old St Mellons, St Mellons

Comparison with neighbouring postcode sectors

The table below shows how 'CF3 6' compares to neighbouring postcode sectors.

Postcode sector Lower quartile Middle quartile Upper quartile
CF3 2 Marshfield £2,820 sqm £3,390 sqm £3,920 sqm
CF3 5 Llanrumney £2,210 sqm £2,500 sqm £2,810 sqm
CF3 6 Old St Mellons £3,200 sqm £3,710 sqm £4,010 sqm
CF3 3 Rumney £2,320 sqm £2,760 sqm £3,280 sqm
CF3 0 St Mellons £2,640 sqm £3,130 sqm £3,440 sqm
CF3 4 Llanrumney £1,990 sqm £2,360 sqm £2,750 sqm
CF3 1 Rumney £2,010 sqm £2,220 sqm £2,610 sqm

Will St Mellons house prices drop in 2024?

I cannot tell the future and don't believe anyone who says they can. I can however plot price trends - I have done this in the chart below for CF3 6 (Old St Mellons) compared with both the wider area CF3 and inflation (CPIH from the Office of National Statistics). The dashed trend lines in the chart show the average over time.

Historic price per square metre in Old St Mellons,St Mellons
House price trends for Old St Mellons

For the most recent sales activity, rather than a summarized average, it is better to see the underlying data. This is shown in the chart below, where blue dots represent individual sales, click on them to see details. If there is an obvious trend you should be able to spot it here amid the noise from outliers.

Most recent CF3 6 sales
Recent trends for Old St Mellons

Data from Land Registry comes in gradually over time. I update it every month but it takes about 5 months for the majority of sales for St Mellons to be recorded. Disclaimer: I do not verify and cannot guarantee the accuracy of any data shown. Outliers exist in the data, typically these are where the EPC registry records the internal area incorrectly, sometimes although very rarely the Land Registry price paid data can be wrong. The data provided throughout this website about St Mellons and any other area, is not financial advice. Any information provided does not and cannot ever take in to account the particular financial situation, objectives or property needs of either you or anyone reading this information.

Street level data

Street Avg size Avg £sqm Recent sales
Mortimer Avenue, Old St Mellons, CF3 6Y 83 sqm £3,201 34
Heol Bennett, Old St Mellons, CF3 6A 122 sqm £3,060 21
Heol Booths, Old St Mellons, CF3 6W 79 sqm £3,389 21
Heol Williams, Old St Mellons, CF3 6A 78 sqm £3,478 13
Boyce Way, Old St Mellons, CF3 6A 67 sqm £3,474 11
Rhodfa Lewis, Old St Mellons, CF3 6Y 147 sqm £2,820 11
Lewis Crescent, Old St Mellons, CF3 6Y 83 sqm £3,051 10
Druidstone Road, Old St Mellons, CF3 6X 280 sqm £3,847 9

Search for your street here.

New build activity

Street Avg size Avg £sqm New build sales
Church Road, Old St Mellons, CF3 6A 66 sqm £2,926 20
Clos Thomas, Old St Mellons, CF3 6Y 83 sqm £3,131 23
Church Road, Old St Mellons, CF3 6Y 95 sqm £2,849 13

Church Road, Old St Mellons, CF3 6A has seen 20 new build sales in the last 4 years (average price £195,052). These new build homes typically have an internal area of 66 sqm, with an average price of £2,926 sqm. This £sqm average is £-784 below the average for CF3 6. New builds typically command a £ per sqm premium. In the case of Church Road the premium seems not to exist. Without more info we can only speculate why this may be. Perhaps it may be greater density and smaller gardens, but this is just a guess.

Raw data

Our analysis of Old St Mellons is derived from what is essentially a big table of sold prices from Land Registry with added property size information. Below are three rows from this table to give you an idea.

Address Paid sqm £/sqm
185, Mortimer Avenue, Old St Mellons, St Mellons £260,000
94 2,765
30, Heol Williams, Old St Mellons, St Mellons £311,000
99 3,141
8, Heol Booths, Old St Mellons, St Mellons £215,000
51 4,215

See the entire list of all sales in Old St Mellons (CF3 6) here.


I created HouseMetric because I wanted to see this data and analysis myself, I also wanted to teach myself to build a website. Please give me feedback or spread the word about it. I'm constantly tinkering and adding more stuff to it.