House prices in SL9 (Chalfont St Peter)

Price per square metre data and charts to help you understand the housing market in SL9 - stats were last calculated on 01 December 2025.

Defining 'SL9'

This analysis is limited to properties whose postcode starts with "SL9", this is also called the postcode district. There are no official postcode district names so I've just labelled it SL9, Chalfont St Peter. It is shown in red on the map below.

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Price per square metre

Knowing the average house price in SL9 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 2025, 3, Lambscroft Way, Chalfont St Peter, SL9 9AY sold for £640,000. Given the internal area of 80 square metres recorded on the EPC, the price per sqm is £640,000 ÷ 80 sqm = £8,000.

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 SL9 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 SL9

The chart above is called a histogram, it helps you see the distribution of house price per sqm in SL9 To make this chart we put all the sales data into a series of £ per sqm 'buckets' (e.g. £6,250 to £6,500, £6,500 to £6,750, £6,750 to £7,000 etc...) we then count the number of sales with within in each bucket and plot the results. The histogram is based on 517 sales that took place in SL9, 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 SL9, Chalfont St Peter. Notably, only 25% of properties that sold recently were valued at more than £7,010 sqm. For anything to be valued more than this means it has to be more desireable than the clear majority of SL9 homes.

Box plot of £ per sqm for SL9

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. Chalfont St Peter. The chart above shows a boxplot for 'SL9' as well as the 'SL' 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 'SL9' is £6,000.
  • 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 517 transactions in SL9, Chalfont St Peter half were sold for between £5,380 and £7,010 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; 517 for SL9, Chalfont St Peter.

    • Property price map for Chalfont St Peter

    Have a look at the interactive price map I created for myself. Use it to explore 'SL9' house prices all the way down to individual property plots.

    Property price heatmap for Chalfont St Peter
    House price map for Chalfont St Peter

    Will SL9 house prices drop in 2025?

    House prices in SL9 fell -0.3% in the last year, -4.0% after inflation. Whether or not this trend will continue depends on many factors, such as wage growth, net migration, interest rates and the level of house building. No one can predict these things with certainty however we can plot the historic trends in house prices in SL9 (Chalfont St Peter) compared with the wider postcode area 'SL'.You can extrapolate from this based on your own views.

    House price index for SL9

    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 'SL9' property prices over the last 20 years. The index is calculated from the average price paid per sqm for property in SL9 and is set to 100 in 2004. The chart compares trends for SL9, Chalfont St Peter against those of the broader postcode area 'SL'. 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 Buckinghamshire 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 SL9
    SL area SL9 district
    Nominal Real Nominal Real
    20 yr per annum 3.5% 0.7% 3.6% 0.8%
    20 yr total 99.2% 15.5% 102.3% 17.3%
    10 yr per annum 2.3% -0.8% 1.5% -1.5%
    10 yr total 25.8% -7.6% 16.6% -14.4%
    5 yr per annum 2.1% -2.4% 1.4% -3.0%
    5 yr total 10.7% -11.3% 7.1% -14.2%
    1 yr per annum 0.6% -3.2% -0.3% -4.0%
    1 yr total 0.6% -3.2% -0.3% -4.0%

    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, SL9 district have seen a 0.8% annual change when adjusted for inflation. This translates to a total change of 17.3% in real terms.
    • Over the past 5 years, SL9 district have seen a -3.0% annual change when adjusted for inflation. This translates to a total change of -14.2% in real terms.

    Most recent SL9 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
    Grange Road, , SL9 9F 71 sqm £5,219 22
    High Street, , SL9 9Q 60 sqm £5,444 16
    Fulmer Drive, , SL9 7H 331 sqm £6,011 15
    Criss Grove, , SL9 9H 107 sqm £6,234 12
    Leachcroft, , SL9 9L 89 sqm £5,412 12
    Windsor Road, , SL9 7N 353 sqm £5,234 12
    Hill Rise, , SL9 9B 172 sqm £6,879 11
    Joiners Lane, , SL9 0A 148 sqm £7,101 11

    Search for your street here.

    Nearby geographies

    The table below shows how 'SL9' compares to the other postcode districts nearby 'SL9'.

    District Lower quartile Median Upper quartile Sales in last 2yr
    WD3 Croxley Green £5,350 sqm £6,310 sqm £7,140 sqm 1,013
    UB9 Harefield £4,860 sqm £5,540 sqm £6,340 sqm 332
    UB8 Uxbridge £4,800 sqm £5,480 sqm £6,160 sqm 675
    SL9 Chalfont St Peter £5,380 sqm £6,000 sqm £7,010 sqm 517
    SL8 Bourne End £5,000 sqm £5,730 sqm £6,440 sqm 188
    SL7 Marlow £5,380 sqm £6,390 sqm £7,350 sqm 515
    SL6 Maidenhead £4,680 sqm £5,360 sqm £6,180 sqm 2,104
    SL5 Ascot £4,890 sqm £5,730 sqm £6,590 sqm 759
    SL4 Windsor £4,920 sqm £5,620 sqm £6,440 sqm 1,080
    SL3 Slough £4,540 sqm £5,210 sqm £6,090 sqm 757

    Raw data

    Our analysis of SL9 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
    3, Lambscroft Way, £640,000
    Oct-2025
    		 80 8,000
    Hampden House, Churchfield Rd, £730,000
    Oct-2025
    		 141 5,177
    32, Gaviots Way, £995,000
    Oct-2025
    		 125 7,960

    See the entire list of all sales in SL9 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.