Why Every Surveyor Should Understand the Difference Between the Code of Measuring Practice and IPMS

Property measurement is one of the most fundamental skills of a surveyor. Whether undertaking a valuation, preparing sales particulars, carrying out a development appraisal or measuring accommodation for lease purposes, accurate and consistent measurement underpins professional advice.

However, one area that often causes confusion—particularly amongst APC and AssocRICS candidates—is the difference between the RICS Code of Measuring Practice and the International Property Measurement Standards (IPMS).

With the Royal Institution of Chartered Surveyors (RICS) currently consulting on the 7th Edition of the Code of Measuring Practice, now is an ideal time to revisit these important standards.

Why do measurement standards matter?

Measurements are relied upon by clients, lenders, developers, investors, solicitors and occupiers. A difference in the basis of measurement can lead to different reported floor areas, which may influence:

• Property valuations.

• Marketing particulars.

• Rental assessments.

• Development appraisals.

• Service charge calculations.

• Investment decisions.

For this reason, surveyors must always be clear about which measurement standard has been adopted.

The Code of Measuring Practice

The RICS Code of Measuring Practice has historically been the principal UK standard for measuring property.

It introduced familiar measurement bases including:

• Gross External Area (GEA)

• Gross Internal Area (GIA)

• Net Internal Area (NIA)

These measurements continue to be widely used throughout the UK property industry and remain common within agency, valuation, development and construction work.

Many existing leases, valuation reports and planning documents still refer to these measurement definitions.

International Property Measurement Standards (IPMS)

As property markets have become increasingly global, the need for internationally consistent measurement standards has grown.

The International Property Measurement Standards (IPMS) were developed to create a common language for measuring buildings across different countries.

Rather than using GEA, GIA and NIA, IPMS introduces measurement categories including:

• IPMS 1

• IPMS 2

• IPMS 3

Each serves a different purpose depending upon the type of building and the intended use of the measurement.

The adoption of IPMS allows investors, developers and occupiers operating internationally to compare properties on a consistent basis.

Are GIA and IPMS the same?

No.

This is one of the most common misconceptions encountered during APC interviews.

Gross Internal Area (GIA) is not an IPMS measurement.

Although some measurements may appear similar, they are produced using different measurement methodologies and can produce different floor areas.

A professional surveyor should therefore never state that they have measured a building using "GIA under IPMS."

Instead, they should clearly identify the standard used, for example:

• Gross Internal Area (GIA) measured in accordance with the RICS Code of Measuring Practice.

• IPMS 2 measured in accordance with the International Property Measurement Standards.

Why this matters for APC candidates

Measurement is frequently examined during the APC and AssocRICS assessment.

Candidates should be able to explain:

• The different measurement bases.

• Why a particular standard was selected.

• The practical implications of using one standard over another.

• How different standards may produce different reported floor areas.

Simply knowing how to use a laser measure is not enough. Assessors expect candidates to understand the professional standards that underpin their work.

The future of property measurement

RICS is currently consulting on the 7th Edition of the Code of Measuring Practice, demonstrating that property measurement continues to evolve alongside changes in professional practice and international standards.

Surveyors should keep themselves up to date with these developments and ensure they always work in accordance with the latest professional guidance.

Final thoughts

Property measurement may seem straightforward, but selecting the correct measurement basis is a professional judgement that directly affects the advice provided to clients.

Whether you are an APC candidate preparing for your final assessment or an experienced surveyor wishing to refresh your knowledge, understanding the distinction between the Code of Measuring Practice and IPMS is an essential part of professional competence.

At Surveyor Store Ltd, we are developing a range of Reading & Reference Lists covering the RICS Mandatory Competencies. These guides bring together the key professional standards, legislation and guidance documents that every APC and AssocRICS candidate should know, helping you focus your revision and prepare with confidence.

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