House price per square foot: a Derry valuation guide

How to calculate house price per square foot

Divide the property price by its floor area in square feet. If your measurements are in square metres, divide by that area instead to get the price per square metre. Keep the same units throughout the comparison.

The calculation is simple, but choosing the inputs matters. An asking price produces an asking-price rate. An agreed or completed sale price produces a different kind of evidence. Label each figure so you do not mistake a seller's ambition for a result achieved in the market.

For a homeowner in Derry or Londonderry, this can be a useful way to compare the size of competing homes. It is a cross-check, not a shortcut to a dependable asking price.

Write down the evidence before calculating

For each comparison, record the address or listing, property type, price, price status, date, floor area, measurement source and any obvious differences. Keep the original floor plan or listing alongside your notes so you can revisit the calculation.

Do not add advertised room dimensions together and assume you have a comparable total. Check whether the floor-area figure includes circulation space, a garage, outbuildings or other accommodation. If the measurement basis is unclear, mark the comparison as uncertain.

Avoid comparing an apartment measured on one basis with a detached home measured on another. A precise-looking answer can still be misleading when the underlying areas do not describe the same thing.

Why the lowest rate is not automatically the best value

RICS valuation standards recognise price per square metre or square foot as a possible unit of comparison, but require consistent use and consideration of differences between properties. Location, specification and the nature of the property still matter.

In practice, use your notes to explain the result. Does one property need work? Is the extra floor space usable in the way your household needs? Does the garden, parking or access arrangement change its appeal? Those questions belong beside the arithmetic.

Two homes with the same bedroom count may offer very different layouts. Equally, a larger house is not necessarily the right comparison for a smaller home simply because both are nearby. Start with the closest matches, then consider the differences.

Is there one price per square foot for Derry?

This guide does not claim a single verified rate for Derry. A headline Northern Ireland average, a portal asking-price sample and a small group of local completed sales describe different evidence. They should not be combined into one local benchmark without checking their coverage.

BT47 and BT48 also contain a range of property types and settings. Use a postcode to narrow your search, then examine the actual street, property and comparison dates. Do not copy a rate from a different city and multiply it by your floor area.

Our guide to sold house prices in Northern Ireland explains why the source and status of a price need checking.

Use it alongside your valuation range

Run your House Price Derry guide estimate using the property details as they stand today. Compare the result with your evidence notes. If they differ sharply, check the price status, floor area and property match before deciding that either figure must be right.

The HPD result is not calculated by multiplying the rate in this article by your floor area. Read the methodology and the source explanation supplied with your result to understand what has actually been used.

Enter your name and email to view the guide range and receive your report. House Price Derry follow-up is optional, and estate-agent contact requires a separate choice naming the agent.

Start with the free Derry valuation guide for your postcode and property type.

Read how the valuation works before using the figure for planning.

When to ask for a property-specific assessment

Take your comparison notes to a local appraisal when preparing to sell. Ask which properties are the closest matches, what their price status is and how differences in condition and accommodation affect the advice.

For a mortgage, tax, legal or other formal purpose, establish the required valuation with the relevant qualified professional. A floor-area calculation and an online guide do not replace that assessment.