Price Per Square Foot Calculator

What this calculator does

Price per square foot is the simplest way to normalise properties of different sizes: purchase price divided by internal floor area. Enter the price and the area — in square feet or square metres — and the calculator returns the rate, with a table so you can place several properties on the same scale.

It answers exactly one question, which is how much you are paying for space, and it answers it cleanly. What it excludes is everything else that drives UK values: garden size, parking, condition, lease length, service charges, EPC rating, and precise location. That makes it a quick comparison within a tightly defined local set and unreliable the moment you widen the net.

When to use it

It works best comparing similar properties on the same street or within the same development, where the factors it ignores are broadly equal. In a road of near-identical Victorian terraces, it is a fair way to spot which asking price is out of line.

Two further uses justify it on their own. First, sizing an extension or loft conversion: comparing the build cost per square foot against what finished space sells for locally answers immediately whether the work creates value. Second, learning an unfamiliar area — running the calculation across fifteen or twenty recent sold prices establishes the local rate faster than anything else, and gives you a reference for every listing thereafter.

Understanding the inputs

Property price should be a Land Registry sold price when you are building comparables and the asking price when you are assessing a listing. Do not mix the two, since asking prices generally sit above achieved prices.

Area is the input that causes trouble, because UK listings frequently omit it. The EPC register is the most consistent source and reports gross internal area in square metres — divide by 0.0929, or multiply square metres by 10.76, to convert to square feet. Be consistent about whether conservatories, garages, and loft conversions are included. Comparing a figure that includes a converted loft against one that does not will mislead you by ten percent or more.

How is this calculated?

Price Per Sq Ft = Property Price / Total Area

A worked example

Take a house on the market at £425,000 with an EPC-recorded floor area of 109.6 square metres, or about 1,180 square feet. That works out at roughly £360 per square foot, or about £3,877 per square metre.

If sold prices for similar houses on the street average £340 per square foot, the asking price is roughly six percent above the local rate — enough to warrant a question about condition or a slightly lower offer, not enough to walk away. Now use the same rate on an extension. A 20 square metre single-storey rear extension quoted at £60,000 costs about £279 per square foot to build against finished space valued at £360, so it adds roughly £77,500 of value for £60,000 of spending — provided the local ceiling price is not already close.

Limitations and assumptions

The metric ignores garden size and off-street parking, both of which carry serious weight in UK pricing, and it ignores condition, so a refurbished property and a tired one look identical. On flats it ignores service charge, ground rent, and lease length, any of which can move value by twenty percent while the rate stays unchanged.

Floor area figures also disagree between sources — an EPC, an agent's floorplan, and a surveyor's measurement can differ by five percent or more depending on how conservatories and converted spaces are treated, and that alone shifts the rate. It also cannot see a local ceiling price, which is what stops an over-extended house recovering its build cost. Use it to generate questions, then rely on sold comparables and a survey to answer them.