About the IRP Market Data Centre Methodology & Definitions

The IRP Market Data Centre combines researched market intelligence with first-party eCommerce benchmark data to provide a quantitative view of UK and Irish eCommerce. 

The Market Data Centre brings together three distinct datasets:

• Market Data – Estimated market sizes and market structure.
• Merchant Data – Estimated merchant online turnover and market position.
• Benchmark Data – Operational eCommerce metrics calculated directly from trading data within the IRP platform.

Together these datasets help merchants understand their markets, benchmark their performance and make better commercial decisions.

The Market Data Centre currently focuses on B2C eCommerce within Great Britain, Northern Ireland and Ireland. We separated Nothern Ireland from the UK as Northern Ireland currently has a unique position of free trade to the EU and United Kingdom.

Independent Merchant Market Share

A large proportion of UK and Irish eCommerce is controlled by major retailers and marketplaces with Amazon taking up close to 30% of UK eCommerce and the top 10 taking 50% share collectively.

IRP uses approximately 30% as a working estimate of the market represented by independent SME and mid-market merchants. The actual proportion varies significantly between market verticals.

Even at 30%, the independent opportunity remains substantial. Within a £200 billion UK eCommerce market, this would represent approximately £60 billion in annual online sales.

This estimate is intended to help independent merchants understand the scale of the market available to them rather than define an exact share for every sector.  This SME sector is the area that IRP is primarily interested in - for example we list smallers Merchants in a market like Baby and Nursery rather than Amazon and eBay.  We do however take the total size of the Vertical.

Market Size Estimates in Market Data

There is no single authoritative source for the size of every eCommerce market. Published estimates often differ because of varying definitions, methodologies and market boundaries.

IRP estimates market sizes using multiple sources, including:

• Government statistics
• Industry and sector reports
• Public company accounts
• Merchant websites
• Marketplace information
• Trade publications
• Search and traffic estimates
• IRP market research
• First-party IRP trading data where appropriate

Where several sources are available, IRP compares the available evidence and adopts the estimate considered most representative of the defined market.

Market size figures should therefore be regarded as informed estimates rather than audited values and are reviewed as better information becomes available.

Estimating Merchant Online Turnovers

Most merchants do not publish their online turnover separately from other business activity.

Many combine online and physical retail, B2C and B2B sales, marketplaces, international trading and multiple websites. Direct measurement is therefore rarely possible. We are estimating their B2C online turnovers only.

IRP estimates online turnover using observable commercial indicators, including:

• Estimated website traffic
• Market conversion rates
• Average order values
• Product pricing
• Public company information
• Search visibility
• Marketplace presence
• Sector knowledge

A simplified turnover estimate is based on:

Estimated Sessions × Estimated Conversion Rate × Estimated Average Order Value

Merchant turnover figures are intended to indicate relative online scale and market position. They should not be interpreted as audited financial information.

IRP welcomes feedback where merchants believe published estimates can be improved.

Ecommerce Benchmark Data

The distinguishing feature of the IRP Market Data Centre is its first-party benchmark data.

Unlike survey-based reports, benchmark metrics are calculated directly from operational trading data recorded within the IRP platform using consistent definitions, attribution methods and calculations.

Benchmark data currently includes metrics such as:

• Sales Growth
• Sales Forecast
• Cost Per Acquisition
• Conversion Rate
• Average Order Value
• Average Selling Price
• Traffic Channel Share
• Others

Benchmark figures are aggregated to protect the confidentiality of individual merchants.

Calculations are performed using the underlying trading data before published values are rounded for presentation.

Ecommerce Attribution

Traffic-channel reporting uses IRP's first-party Last Click Attribution model.

Each completed order is attributed to the final recognised traffic source before purchase. This provides a consistent method for calculating channel revenue, channel share and marketing cost across all merchants.

Free traffic — including direct visits, organic search and unpaid referrals — is grouped under Direct.

No attribution model captures every customer interaction. IRP uses Last Click because it provides a clear, transparent and repeatable standard for benchmarking.