4,272,535 businesses employ nobody but their owners; 8,335 hold 49% of the turnover.
B2B market sizing tends to start from an inherited number. The underlying counts are public, current and free, and they break down by size and by place, which is what a plan needs. The sources sit on the series hub.
Three answers to one question
The UK has 5.7 million businesses for total demand, 2.73 million findable on the register, 2.9 million active in the year. Match the number to the claim.
How many businesses does the UK have? The Business Population Estimates say 5.7 million. The ONS register, which counts only businesses registered for VAT or PAYE, says 2.73 million. Business demography puts about 2.9 million active at some point in 2024. All three are official, and none of them is wrong, because they answer different questions. The 5.7 million includes an estimated 3.0 million unregistered traders. The 2.73 million is a March snapshot of the register. The 2.9 million counts businesses active at any point in the year.
The method is to pick the number that matches the claim. If you are sizing total demand for something any sole trader might buy, start from 5.7 million. For an addressable market you can find by industry and geography, use 2.73 million, because targeting runs on the register and the unregistered are invisible to it. Churn questions go to the demography series.
Each band is a different buyer
At zero employees the buyer is one person; past 250 staff there is a committee, a procurement function and an incumbent. A plan that treats them as one audience has averaged four markets.
Within the 5.7 million: 4,272,535 businesses employ nobody but their owners, 1,150,875 employ one to nine people, 220,085 employ ten to 49, 38,435 employ 50 to 249, and 8,335 employ 250 or more. That last band is 0.15% of businesses and holds 49% of all private sector turnover.
The no-employee business is one person making a household-scale decision. Somewhere in the one-to-nine band a first office manager starts making purchases. In the ten-to-49 band the first specialist hires arrive and buying gets a process. Past 250, there is a committee, a procurement function and an incumbent.
Treat “businesses” as one audience and you are planning for four markets that share nothing but a legal status.
Births and deaths
317,000 new businesses formed in 2024, and every new registration lands on the register by quarter and local authority.
317,000 new businesses formed in 2024, an 11.1% formation rate, against 280,000 closures, and 38.4% of the 2019 cohort survived to five years.
One business in nine is brand new this year.
New businesses formed in 2024, against 280,000 closures: a formation rate of 11.1% against the active register.
Measured. Note 3. · gabrielgruter.com
A new business has no incumbent supplier. That is a formation rate of 11.1% against the active register, not against the 5.7 million headline.
And all of it maps. The register serves enterprise counts by headcount, by industry to five-digit code, and by geography down to local authority. Manchester holds 23,715 registered enterprises on the 2025 snapshot. The same table sizes the market by city, by industry and by headcount.
What I would do
Build the market size from the bands, give new-business formation its own budget line, and weight geography by enterprise density.
Build the market size from the bands, not the headline, and show the working, because a finance director can check these numbers and the ones who matter will. Give new-business formation its own plan and its own budget line. Weight B2B geo by enterprise density, which is what the geography piece covers in general form.
Where this argument is weakest
The register trails reality by up to a year, the unregistered 3.0 million rest on survey estimates, and headcount is a rough proxy for budget.
The register snapshot is from March 2025 and updates annually, so it always trails reality. The unregistered 3.0 million rest on survey-based estimation that the release itself flags as uncertain. Size bands classify by headcount, and headcount is a rough proxy for budget: a 40-person firm can outspend a 200-person one on the right category. A count of businesses is not a count of demand, either, which is why this piece pairs with who buys B2B finance, where the bands get an actual category run through them.