Penetration testing cost: what UK businesses (10–200 staff) should budget for

If you run a business with 10 to 200 people in the UK, you’ve probably heard the phrase “penetration testing” bandied about. It sounds expensive and technical — and yes, it can be both. But more useful than the tech waffle is a plain answer to this question: how much should you expect to pay, and what business benefit do you get for the money?

Why penetration testing matters (in plain business terms)

Penetration testing is essentially a simulated attack on your systems. The aim isn’t to beat an attacker at cyber-nerd chess; it’s to find the weak bits before someone with worse intent does. For UK firms the business impacts are clear: avoid downtime, protect customer data (and the GDPR headaches that come with losing it), preserve reputation and keep contracts with suppliers who insist on security checks.

What affects penetration testing cost?

There isn’t a single price tag because the cost depends on the aim and the size of the target. Key factors include:

• Scope — external internet-facing systems are cheaper to test than an entire estate of servers, laptops and bespoke applications.
• Type of test — a web-application test, an internal network test, a wireless assessment or social engineering (phishing) are different beasts.
• Complexity — custom applications, legacy systems, and hybrid cloud setups need more time and specialist skills.
• Depth — a light vulnerability scan is much cheaper than a thorough manual penetration test that tries to chain vulnerabilities together.
• Remediation and retest — many providers offer a follow-up retest once fixes are applied; that adds cost but closes the loop.
• Credentials and insurance — ensuring testers hold recognised qualifications and professional indemnity/PCIDSS insurance can increase price, but it’s worth it.

Typical price ranges (realistic ballpark)

Every provider will have their own pricing, but for UK businesses of your size, expect the following broad ranges:

• Basic external penetration test / single web application: roughly £1,000–£4,000. This is a focused, short engagement testing public-facing systems.
• Comprehensive internal + external test (mid-sized estate): typically £4,000–£12,000. Suitable for businesses with multiple servers, internal networks and a few bespoke apps.
• Large or complex engagements: £12,000–£30,000+. This covers complex cloud environments, multiple web apps, wireless, and social-engineering components.

These ranges are guidance, not a quote. VAT, emergency scheduling and urgent retests will increase costs. On the flip side, a tight, well-defined scope often brings better value.

What you get for your money (business outcomes)

Good penetration testing isn’t a compliance tick-box. It should deliver:

• Clear prioritised findings — the few issues that would actually hurt your business first.
• Practical remediation advice — not just a list of CVEs and scary IDs, but steps your IT team can action.
• Risk-based scoring — so board members can understand the business impact and set budgets accordingly.
• Retest options — verify the fixes worked; otherwise you’re paying for a paper exercise.

How often should you test?

At a minimum, test annually. But you should also test after significant changes — a new web app launch, a major migration to the cloud, or after serious security incidents. For firms handling payment data or regulated information, testing more frequently is sensible and often required by partners.

Choosing a provider: questions to ask (and why they matter)

When you’re getting quotes, ask for plain answers to these points — they’ll expose whether you’re getting value or just marketing:

• What exactly is in scope? Ambiguity costs money. Define targets, timing and allowed techniques.
• Who will do the work? Ask for experience relevant to your stack — people who’ve seen UK businesses and supply-chain quirks before often go faster.
• What are the deliverables? You want an executive summary, a technical appendix, and remediation steps with prioritisation.
• Is retesting included? A retest after fixes is vital to close the loop.
• How will they run disruptive tests? You need assurances that testing won’t take systems offline at a busy time.

If you need wider advice on security strategy or follow-up work, consider suppliers who also provide ongoing services — it reduces context switching and saves time. For example, many firms pair penetration testing with broader cyber security services to turn findings into long-term improvement plans.

Getting the best value

Price per se isn’t the only consideration. Cheaper providers may rely heavily on automated scans that throw up lots of low-value noise. The best value often comes from teams who combine automated tools with hands-on, experienced testers who understand which vulnerabilities actually matter to your business.

Small budget? Prioritise wisely

If you can only afford one test, test what faces the internet: your website, remote access and email gateways. That’s where attackers most often start. Then plan a schedule to cover internal systems and staff phishing over the next 12 months.

FAQ

How long does a typical penetration test take?

Short tests (single web app) can be done in a few days. Comprehensive internal and external tests typically take one to three weeks including reporting. Remember to allow extra time for remediation and retest.

Will penetration testing disrupt my business?

Responsible testers minimise disruption and agree a test window. Some intrusive tests can risk service interruption, so plan them during quieter periods and agree rollback procedures.

Does penetration testing satisfy GDPR requirements?

Penetration testing helps demonstrate appropriate technical measures under GDPR, but it’s one piece of a wider data protection programme. Keep records, act on findings, and integrate testing into your wider compliance work.

Is it better to use an external firm or an in-house team?

External teams bring fresh eyes and varied experience. In-house teams are useful for continuous testing. Many UK businesses combine both: external tests annually, with in-house checks more frequently.

How quickly should I act on high-risk findings?

High-risk issues deserve immediate attention — days, not weeks. Medium and low risks can be scheduled, but make sure there’s accountability and deadlines.

Penetration testing cost varies, but think of it as an insurance premium that buys time, money and credibility. A well-scoped test prevents embarrassing outages, costly data breaches and the scramble to explain to customers and regulators. If you budget sensibly and pick the right provider, you’ll sleep easier knowing you’ve reduced the risk of a disruptive surprise.

Tip: start with a clear scope, focus on business-critical assets, and insist on practical remediation and a retest. The result should be fewer nasty surprises, lower likely downtime and better evidence of security for partners — all of which save money and hassle in the long run.

Ready to reduce risk and protect time, money and reputation? Plan a sensible test, prioritise follow-up fixes, and book a retest — the calm that comes after is worth the investment.