House prices in SN8 (Marlborough)

This article shows price per square metre data and various charts to help you understand the housing market in SN8 - stats were last calculated on 03 December 2024.

Defining 'SN8'

This analysis is limited to properties whose postcode starts with "SN8", this is also called the postcode district. There are no official postcode district names so I've just labelled it SN8, Marlborough. It is shown in red on the map below.

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Price per square metre

Knowing the average house price in SN8 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

For example in October 2024, 148, High Street, Marlborough, SN8 3AB sold for £237,500. Given the internal area of 115 square metres recorded on the EPC, the price per sqm is £237,500 ÷ 115 sqm = £2,065.

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 ;-). It is a huge pain to code the automatic conversion for square meters to square feet for all the graphs and charts on SN8 and elsewhere. All the conditionals turn my tidy code for into spaghetti. I will get around to it at some point, but for now you can just divide everything by 10 in your head, move a decimal place and you'll be close enough. If you want to be more precise 1 sqm = 10.76391 sqft.

Distribution of £ per sqm for houses vs flats in SN8

The chart above is called a histogram, it helps you see the distribution of house price per sqm in SN8 To make this chart we put all the sales data into a series of £ per sqm 'buckets' (e.g. £4,250 to £4,500, £4,500 to £4,750, £4,750 to £5,000 etc...) we then count the number of sales with within in each bucket and plot the results. The histogram is based on 479 sales that took place in SN8, in the last 24 months.

Generate a custom histogram like the one above but based on your own criteria.

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 SN8, Marlborough. Notably, only 25% of properties that sold recently were valued at more than £4,910 sqm. For anything to be valued more than this means it has to be more desireable than the clear majority of SN8 homes.

Box plot of £ per sqm for SN8

Tip: click on the chart to see the values.

The chart above is called a boxplot (or a box-and-whisker plot). Box plots, like histograms, are used to graphically represent the distribution of data, showing the central tendency, spread of the distribution. In the context of £ per square metre property price distributions, box plots represent the variation in property prices within a geographic area e.g. Marlborough. The chart above shows a boxplot for 'SN8' as well as the 'SN' postcode area.

  • Median: The horizontal line inside the box represents the median (£ per square meter). This is the midpoint of the data, meaning 50% of the prices are below this value, and 50% are above. The middle price per square metre in 'SN8' is £4,220.
  • Interquartile Range (IQR): The box spans from the 25th percentile (Q1) to the 75th percentile (Q3). This is the range where the middle 50% of the data lies, giving a good indication of the typical price spread. Of the 479 transactions in SN8, Marlborough half were sold for between £3,480 and £4,910 per square metre.
  • Whiskers: In our case, the whiskers extend from the 9th percentile (at the lower end) to the 91st percentile (at the upper end), This provides a slightly broader view of the distribution by including the middle 82% of records. The whiskers capture most of the variation but exclude extreme outliers caused by data errors in recording sold house prices or internal area.
  • 'n=' is the number of property transactions the box plot is based on; 479 for SN8, Marlborough.

    • Property price map for Marlborough

    Have a look at the interactive price map I created for myself. Use it to explore 'SN8' house prices all the way down to individual property plots.

    Property price heatmap for Marlborough
    House price map for Marlborough

    Will SN8 house prices drop in 2025?

    I cannot tell what house prices will do in the future and don't believe anyone who says they can. However we can plot price trends, I have done this in the chart below for SN8 (Marlborough) compared with the wider postcode area 'SN'. You can extrapolate from this based on your own views on future interest rates, inflation and other factors.

    House price index for SN8

    Tip: click on the legend items to show/hide different lines

    Download house price index as CSV (premium users only).

    The chart above shows changes in 'SN8' property prices over the last 20 years. The index is calculated from the average price paid per sqm for property in SN8 and is set to 100 in 2004. The chart compares trends for SN8, Marlborough against those of the broader postcode area 'SN'. What is more interesting is to look at the difference between flats and houses, even those in the same area follow a very different trend, to get a robust enough sample size to see this we need to zoom out and look at house price trends for the entire Wiltshire local authority.

    The dashed lines show nominal house price changes, the solid lines show the same data adjusted for inflation. Economists call this the 'real' price change. You have to take inflation into account when comparing prices over time. It's calculated using the formula:

    Real Rate of Return = (1 + Nominal Rate) ÷ (1 + Inflation Rate) – 1
    In this formula, the nominal rate is the rate of change before any adjustments, and the inflation rate is taken from the Consumer Price Index. The real rate of return is a more accurate measure of change in value, because £1 today does not have the same buying power as £1 in the past. For example, if a savings account pays an interest rate of 3% per year and the inflation rate is 5% per year, the real rate of return is -2%. This means that the investment's value is shrinking by 2% each year.

    Historic returns for SN8
    SN area SN8 district
    Nominal Real Nominal Real
    20 yr per annum 3.0% 0.3% 2.9% 0.3%
    20 yr total 79.7% 6.4% 77.7% 5.3%
    10 yr per annum 4.2% 1.3% 2.9% 0.1%
    10 yr total 50.3% 14.1% 33.1% 1.1%
    5 yr per annum 3.7% -0.4% 3.4% -0.6%
    5 yr total 19.7% -2.0% 18.4% -3.1%
    1 yr per annum -0.8% -4.8% -0.6% -4.6%
    1 yr total -0.8% -4.8% -0.6% -4.6%

    This table complements the house price index chart above, presenting the data in a more detailed format. It breaks down the information into 20-year, 10-year, 5-year, and 1-year periods, further categorized by property type. For each period, we display both a per annum rate of change and a total rate of change.

    The total rate of change represents the overall change over the entire period. The formula for total return is:

    Total return = (Index at end of period ÷ Index at start of period) - 1

    The per annum rate of change is the annualized rate of change over the period. This is equivalent to the annual bank savings rate you would need to achieve the same total return over the given period. This annualized return is also known as the Compound Annual Growth Rate (CAGR). The formula for CAGR is:

    CAGR = (1 + Total return) ^ (1 ÷ Number of years) - 1

    Some specific examples:

    • Over the past 20 years, SN area have seen a 0.3% annual change when adjusted for inflation. This translates to a total change of 6.4% in real terms.
    • Over the past 5 years, SN8 district have seen a -0.6% annual change when adjusted for inflation. This translates to a total change of -3.1% in real terms.

    Most recent SN8 sales

    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.

    Tip: hover over dots to see details

    Street level data

    Street Avg size Avg £sqm Recent sales
    Cherry Orchard, , SN8 4A 91 sqm £3,888 23
    Salisbury Road, , SN8 4A 95 sqm £3,503 21
    London Road, , SN8 2A 112 sqm £3,527 17
    River Park, , SN8 1X 55 sqm £3,226 16
    Priorsfield, , SN8 4A 99 sqm £4,572 16
    George Lane, , SN8 4B 106 sqm £3,256 15
    Church Street, , SN8 3P 130 sqm £4,669 13
    High Street, , SN8 3A 147 sqm £4,440 13

    Search for your street here.

    Nearby geographies

    The table below shows how 'SN8' compares to the other postcode districts nearby 'SN8'.

    District Lower quartile Median Upper quartile Sales in last 2yr
    SP9 Shipton Bellinger £2,700 sqm £3,250 sqm £3,790 sqm 128
    SP4 Amesbury £3,020 sqm £3,570 sqm £4,000 sqm 738
    SP11 Ludgershall £3,070 sqm £3,750 sqm £4,290 sqm 771
    SN9 Pewsey £3,440 sqm £3,920 sqm £4,400 sqm 166
    SN8 Marlborough £3,480 sqm £4,220 sqm £4,910 sqm 479
    SN7 Faringdon £3,220 sqm £3,790 sqm £4,250 sqm 429
    SN6 Highworth £3,290 sqm £3,770 sqm £4,170 sqm 551
    SN5 Grange Park £3,100 sqm £3,550 sqm £3,960 sqm 823
    SN4 Wootton Bassett £2,930 sqm £3,540 sqm £4,050 sqm 725
    SN3 Swindon £2,810 sqm £3,290 sqm £3,800 sqm 1,280

    Raw data

    Our analysis of SN8 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
    148, High St, £237,500
    Oct-2024
    		 115 2,065
    1, Knights Close, £460,000
    Oct-2024
    		 111 4,144
    28, Stonebridge Close, £275,000
    Oct-2024
    		 79 3,481

    See the entire list of all sales in SN8 here.

    About

    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.