Welcome! If you are new to the world of information security standards, you have come to the right place. Let’s strip away the jargon and start with the basics.
In simple terms, ISO 27001 is the international standard for managing information security. Think of it as a rulebook or a blueprint that helps an organisation protect its sensitive data. Certification is simply the official “stamp of approval” from an independent body proving you have followed that rulebook correctly.
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How much does ISO 27001 cost?
This is the most common question we get. The answer isn’t a single price tag; it is a structured journey. To give you a quick answer: costs can range from a few thousand pounds for small businesses doing it themselves, to significantly more for larger enterprises using consultants.
The Big Picture: Your 4-Phase Cost Breakdown
To understand ISO 27001 costs simply, we need to break the financial outlay down into four distinct phases. Here is what you are actually paying for:
- Phase 1: Preparation (£300 to £10,000)
This covers getting ready. It includes buying the official standard documents and conducting an optional “gap analysis” to see where your security currently stands compared to the rules. - Phase 2: Implementation (£500 to £40,000)
This is where the real work happens. You are building your Information Security Management System (ISMS). You might do this via a DIY toolkit, an online platform, or by hiring a consultant. - Phase 3: The Audit (Varies by employee count)
This is the formal test. An external auditor checks your system in two stages. We will break down the specific pricing for this below. - Phase 4: Ongoing Costs (Recurring annually)
Certification requires yearly check-ups and a full recertification every three years.
The Audit Cost: 4 Key Factors That Influence the Price
While preparation and implementation costs are variable based on how much help you hire, the certification audit fee is calculated using a specific formula. Here are the four factors that dictate that price.
1. Company Size (The Primary Driver)
The biggest influence on your quote is the number of employees in your organisation. Certification bodies use your headcount to calculate “audit days”, literally, how many days an auditor needs to verify your system.
The formula is simple: Audit Days x Daily Rate = Total Cost.
Note: The average daily rate for an auditor in the UK is around £1,250. This reflects 2026 market rates.
Here is a table to help you estimate your costs based on your team size:
| Number of Employees | Audit Days Required | Estimated Cost (@ £1,250/day) |
|---|---|---|
| 1 – 10 | 5 | £6,250 |
| 11 – 15 | 6 | £7,500 |
| 16 – 25 | 7 | £8,750 |
| 26 – 45 | 8.5 | £10,625 |
| 46 – 65 | 10 | £12,500 |
2. Certification Scope
The “scope” defines what parts of your business are covered. If you include every department, product, and service, the auditor has more to check, which takes more time. Spending time to accurately define your scope can help manage these expenses significantly.
3. Number of Locations
Do you have multiple physical offices or data centres? If the scope covers multiple sites, the auditor must visit them. This increases the audit days required and adds travel and accommodation expenses to your bill.
4. Choice of Certification Body
Even though the final certificate is the same, different bodies charge different rates. Larger, well-known bodies may charge a premium due to higher overheads and marketing.
Top Tip: Always get at least three quotes. Many bodies use the same pool of freelance auditors, so shopping around ensures you aren’t paying extra just for a brand name.
It’s Not a One-Time Fee: The 3-Year Cycle
Budgeting for ISO 27001 requires long-term thinking. The certificate is valid for three years, creating a recurring cost cycle.
- Year 1 (Initial Certification): The full two-stage audit. (e.g., £6,250 – £12,500 for small firms).
- Year 2 (Surveillance Audit): A mandatory check-up. Costs roughly one-third of the initial fee.
- Year 3 (Surveillance Audit): Another mandatory check-up. Costs roughly one-third of the initial fee.
- Year 4 (Recertification): The cycle restarts. You undergo a full audit again with costs similar to Year 1.
Summary: How to Budget Effectively
To wrap up, here is your cheat sheet for managing ISO 27001 costs:
- Check your headcount: This is your starting point for pricing.
- Define your scope: Don’t over-complicate the audit by including unnecessary departments.
- Shop around: Get three quotes to compare daily rates.
- Plan ahead: Remember to budget for the annual surveillance audits, not just the initial certificate.
About the author
Stuart Barker is a veteran practitioner with over 30 years of experience in systems security and risk management.
Holding an MSc in Software and Systems Security, Stuart combines academic rigor with extensive operational experience. His background includes over a decade leading Data Governance for General Electric (GE) across Europe, as well as founding and exiting a successful cyber security consultancy.
As a qualified ISO 27001 Lead Auditor and Lead Implementer, Stuart possesses distinct insight into the specific evidence standards required by certification bodies. He has successfully guided hundreds of organizations – from high-growth technology startups to enterprise financial institutions – through the audit lifecycle.
His toolkits represents the distillation of that field experience into a standardised framework. They move beyond theoretical compliance, providing a pragmatic, auditor-verified methodology designed to satisfy ISO/IEC 27001:2022 while minimising operational friction.
