Updated on 9 November 2026 by Nicolas Finet, CEO of Sortlist. This guide has been rewritten for 2026: it keeps the definition and formulas, then adds worked UK examples, the difference between penetration rate and market share, how to use penetration in growth strategy (the Ansoff matrix) and common calculation mistakes.
The penetration rate shows what proportion of a defined population uses, owns or buys something. It is one of the simplest and most useful marketing indicators: it tells you how much room a market still has, and how well a campaign is reaching the people you want. This guide explains how to calculate and use it.
Key takeaways
- Penetration rate = (number of customers or users ÷ total target population) × 100.
- It is not market share: penetration compares customers with the total potential population, while market share compares your sales with the sales of all competitors.
- Benchmarks help set targets. In the UK, online sales made up about 27% of retail sales in 2026 (ONS) and about 91% of adults own a smartphone.
What is penetration rate?
The penetration rate is an indicator expressed as a percentage. It measures the proportion of a defined population that has a product or service, or that has been reached by a campaign. The population is whatever you choose to define as the target: all UK households, small businesses in the North West, women aged 25-34, or the customers of a retail area.
“Market penetration rate = (Number of customers/Target market size) x 100.”
nibusinessinfo.co.uk, Market penetration strategy
How to calculate the penetration rate
- Define the target population: be precise about who is included. A vague denominator gives a meaningless result.
- Count the customers or users within that population, over a defined period.
- Divide and multiply by 100.
Example of a company's penetration rate
A UK coffee-machine subscription company targets 800,000 small offices in England. It has 24,000 subscribers.
| Item | Value |
|---|---|
| Target market (small offices in England) | 800,000 |
| Customers | 24,000 |
| Penetration rate | 24,000 ÷ 800,000 × 100 = 3% |
The company then knows that 97% of its target market is untapped, and can ask whether that reflects room for growth or limits such as price, awareness or competition.
Two other types of rate
Penetration in a trading area or at the point of sale. For a shop or restaurant chain, penetration is the share of households in its catchment area that have bought in a given period. It helps decide where to open, where to advertise and how to reach under-served neighbourhoods.
Cumulative penetration. This is the total share of the population that has ever been reached or has ever bought, over several periods. It is useful for products that are bought once or rarely, such as appliances, or for the reach of a campaign across many weeks.
Penetration rate and market share: two different concepts
| Criteria | Penetration rate | Market share |
|---|---|---|
| Compares | Customers with the total population | Your sales with total sales in the market |
| Question answered | How much of the potential market do we reach? | How big are we compared with competitors? |
| Example | 3% of small offices subscribe | We sell 12% of all subscription coffee machines |
| Use | Growth potential and reach | Competitive position |
A product can have low penetration but high market share (a new category with few buyers where you are the main seller), or high penetration but low share (a widely owned product where you are a minor player).
Why use a penetration rate?
A measurement tool for advertising campaigns
Penetration measures how much of your target audience a campaign reached or converted. Compare the rate before and after a campaign, and across regions and segments, to see what worked. It complements reach and frequency; see how to create an advertising campaign.
An indicator to assess the potential of a market
Low penetration suggests room to grow; high penetration suggests a mature market where growth means taking share or finding new uses. Benchmarks give context:
- Smartphone ownership in the UK is about 91% of adults, a mature, near-saturated market.
- Online sales made up about 27% of retail sales in Great Britain in 2026, per ONS data reported by Statista and others, compared with about 19% before the pandemic, a market that has stabilised after rapid change.
- Newer categories, such as electric vehicles or AI subscriptions, have much lower penetration, so growth rates are high.
A guide to growth strategy
The Ansoff matrix lists four growth options: market penetration (existing products, existing markets), product development, market development and diversification. A market penetration strategy aims to sell more of what you already sell to the market you already serve. Common tactics:
- Increase awareness with advertising and PR.
- Improve conversion on the website and in shops; see conversion rate optimisation.
- Adjust pricing, offers and bundles.
- Improve distribution and availability.
- Encourage repeat purchase and loyalty; see customer loyalty.
- Differentiate: see differentiated marketing.
The importance of reliable calculation
- Define the denominator carefully. Counting all UK adults when you only serve small businesses understates your penetration.
- Use consistent time periods. Compare like with like (monthly active customers, not lifetime customers, unless you mean cumulative).
- Use reliable sources: ONS and Ofcom data, industry bodies, and your own CRM data.
- Avoid double counting customers who buy through several channels.
- Segment: penetration by region, age or customer type shows where the opportunity is.
- Be careful with proxies: panel data and estimates carry error. State assumptions.
Penetration rate in other contexts
- Digital and telecoms: internet or broadband penetration is the share of households with access; Ofcom publishes UK figures.
- Software and apps: the share of eligible users who adopt a product or feature.
- Retail: the share of households in a catchment area who shop with you.
- Media: the share of the population reached by a channel or campaign.
Conclusion
Penetration rate is simple to calculate and powerful when the target population is defined well. Use it to size opportunities, to evaluate campaigns and to choose between winning more of the same customers or looking for new ones. Pair it with market share, growth rate and customer value for a full picture.
Frequently asked questions about penetration rate
What is the formula for penetration rate?
(Number of customers or users ÷ total target population) × 100.
What is the difference between penetration rate and market share?
Penetration compares your customers with the total potential population; market share compares your sales with all sales in the market.
What is a good penetration rate?
It depends on the market. Mature products such as smartphones exceed 90% in the UK, while new categories can be under 10%. Compare with your sector and your own history.
What is a market penetration strategy?
A growth strategy that sells more of your existing products to your existing market, using marketing, pricing, distribution and loyalty.
How do I increase penetration?
Raise awareness, improve conversion, adjust offers and availability, and encourage repeat purchase.
What data sources can I use?
Your own customer data, ONS and Ofcom statistics, industry association figures and market research.
Want to grow your market share? Post your project on Sortlist and compare UK marketing agencies for free.
Sources: nibusinessinfo.co.uk, Investopedia, market penetration, Statista, ONS internet sales share, Switchity, UK mobile statistics (Ofcom data). The coffee-machine example is hypothetical.
