Understanding penetration testing costs is essential for any business planning its security budget. Whether you're preparing for compliance certification, responding to board-level security concerns, or simply taking a proactive approach to cyber risk, knowing what to expect financially helps you make informed decisions and avoid both overpaying and underinvesting.

Typical UK Penetration Testing Costs

In the UK, penetration testing is typically priced either as a fixed-fee engagement or based on day rates. The total cost depends primarily on the scope and complexity of what's being tested.

For small to medium-sized businesses, expect to pay between £3,000 and £10,000 for a standard penetration test. Larger organisations with complex environments—multiple networks, numerous applications, or hybrid cloud infrastructure—should budget £20,000 or more.

Day rates from reputable UK penetration testing companies typically fall between £1,000 and £1,500. Rates below £500 per day should raise concerns about the quality and depth of testing you'll receive. Conversely, rates above £2,000 per day are usually only justified for highly specialised work, such as reverse engineering or advanced red team operations.

Costs by Test Type

Different types of penetration tests carry different price tags based on the expertise required and time involved:

• External network testing: £3,000–£6,000. This examines your internet-facing systems and is often the most straightforward engagement.
• Web application testing: £2,500–£8,000. Costs vary significantly based on application complexity, number of user roles, and functionality depth.
• Internal network testing: £5,000–£12,000. These tests require more access and deeper analysis, examining what an attacker could achieve once inside your network.
• Cloud penetration testing: £4,000–£10,000. Testing AWS, Azure, or GCP environments requires specialised cloud security expertise.
• Red teaming: £20,000–£50,000+. These comprehensive exercises simulate real-world adversaries across multiple attack vectors over extended periods.

What Drives the Cost?

Several factors determine where your engagement falls within these ranges:

Scope and complexity are the primary cost drivers. Testing a single web application costs considerably less than assessing an entire corporate network with multiple sites, cloud services, and dozens of applications. A thorough scoping conversation with your testing provider should clarify exactly what's included.

Compliance requirements can affect both depth and documentation. Tests supporting PCI DSS, ISO 27001, or SOC 2 certification often require more rigorous methodology and detailed reporting, which increases costs.

Tester expertise and accreditation matter significantly. CREST-accredited companies with experienced offensive security professionals command higher rates—but they also deliver more thorough, higher-quality assessments. The difference between a checkbox exercise and a genuine security evaluation often comes down to who's doing the testing.

Duration directly impacts cost. According to UK Cyber Security Council data, the average penetration test takes around seven working days, with roughly 60% of engagements using at least two testers. Larger scopes naturally require more time.

Warning Signs of Poor Value

Not all penetration testing delivers equal value. Be cautious of providers who:

• Quote without asking detailed scoping questions about your environment
• Offer rates significantly below £500 per day
• Promise to test everything in just one or two days
• Can't explain their methodology or provide sample reports
• Lack recognised accreditations such as CREST, CHECK, or Tiger Scheme

A surprisingly cheap quote often means you'll receive automated vulnerability scanning dressed up as penetration testing—a very different service that won't identify the business logic flaws, chained vulnerabilities, and creative attack paths that skilled testers find.

Getting Value from Your Investment

To ensure you receive genuine value from your penetration testing budget:

Define your objectives clearly. Are you testing for compliance? Validating specific security controls? Assessing your overall security posture? Clear goals help testers focus their efforts where it matters most.

Provide thorough scoping information. The more accurately a provider understands your environment, the more precise their quote will be. Expect detailed questions about IP ranges, application inventories, authentication mechanisms, and testing constraints.

Ask about methodology. Reputable providers follow established frameworks like OWASP, PTES, or OSSTMM. They should explain their approach and how it maps to your requirements.

Evaluate the deliverables. A quality penetration test report should include an executive summary for leadership, detailed technical findings with evidence, risk ratings, and practical remediation guidance. Ask to see a sample report before engaging.

The Bottom Line

Most UK businesses should expect to spend between £5,000 and £15,000 for a meaningful penetration test. This investment provides genuine insight into your security vulnerabilities and actionable guidance for improving your defences.

While it's tempting to minimise costs, penetration testing is not an area where the cheapest option serves your interests. The goal isn't simply to tick a compliance box—it's to identify real weaknesses before attackers do. A thorough test from experienced professionals delivers substantially more value than a superficial scan at half the price.

When budgeting for penetration testing, focus on finding a provider whose expertise, methodology, and reporting quality match your security needs. The right testing partner becomes a valuable resource for improving your security posture over time, not just a vendor completing a one-off transaction.