ISO 27001 and SOC 2 both prove to buyers that you handle data responsibly, but they are different instruments. ISO 27001 is an international certification awarded by an accredited body; SOC 2 is an attestation report written by a licensed CPA firm. Which you need is driven mainly by where your buyers are and what they ask for.
What is the core difference: a certificate versus an attestation report?
The two frameworks produce different things. ISO/IEC 27001 results in a certificate: an accredited certification body audits your information security management system (ISMS) and, if you pass, issues a pass or fail certification that is recognised internationally. SOC 2 results in a report: a licensed CPA firm examines your controls against the American Institute of Certified Public Accountants (AICPA) Trust Services Criteria and writes a detailed attestation describing what they found.
That distinction matters in practice. A certificate is a short, standardised document a buyer can verify quickly. A SOC 2 report is a longer narrative, often dozens of pages, that a buyer’s security team reads to judge your controls for themselves. One says you passed an independent standard; the other shows the working.
ISO 27001 also carries a defined control set. The current 2022 version lists 93 Annex A controls grouped into four themes: organisational, people, physical and technological. You select and justify which apply in a Statement of Applicability. SOC 2 is built around the Trust Services Criteria, always including Security and optionally Availability, Processing Integrity, Confidentiality and Privacy, with the specific controls tailored to your business rather than fixed by the standard.
Who asks for which, and why?
The decision is usually made for you by your buyers. ISO 27001 is the more widely recognised standard in Europe and internationally; if you are selling to enterprises in the UK, Ireland, mainland Europe, the Middle East or Asia, it is the certification most procurement teams know and ask for. SOC 2 originated in the United States and remains the default in North America, where most enterprise buyers expect to receive a SOC 2 report as part of vendor due diligence.
So the honest first question is not which framework is better, it is which one your customers are already requesting. Look at the security questionnaires landing in your inbox and the contracts stalling in procurement. If the request says SOC 2, ISO 27001 will rarely substitute cleanly, and the reverse is also true. The framework that unblocks revenue is the one your pipeline is asking for.
For startups selling on both sides of the Atlantic, the answer is often both, in sequence. We will come back to how to order that decision below.
How do cost and timeline compare?
Neither framework has a fixed price, and any single figure quoted online should be treated with caution. The real cost of both is driven by the same handful of factors: the size of your organisation, the number of systems and locations in scope, how mature your existing controls are, the amount of internal effort needed to close gaps, and the external auditor’s own fees. The largest variable is almost always internal time, not the audit invoice.
On timeline, the structures differ. ISO 27001 certification runs through a two-stage external audit, a Stage 1 review of your documentation followed by a Stage 2 review of how the system works in practice, and once awarded the certificate is maintained through annual surveillance audits over a three-year cycle. SOC 2 comes in two forms: a Type 1 report assesses the design of your controls at a single point in time, while a Type 2 report assesses how those controls operated across a defined period, which means a Type 2 inherently takes longer because the auditor needs evidence spanning that window. We explain the choice in detail in our guide to SOC 2 Type 1 vs Type 2.
Because the effort sits mostly in building and evidencing controls rather than the audit itself, a company that already holds one framework has a real head start on the other.
Can you do both on one control set?
Yes, and this is the part that changes the economics. The control sets behind ISO 27001 and SOC 2 overlap heavily. Access control, change management, risk assessment, vendor management, encryption, logging, incident response and physical security all appear, in different language, in both. A single well-designed set of controls and the evidence that proves they work can satisfy most of what each framework asks for.
In practice that means you build one security programme, then map it twice: once to ISO 27001’s Annex A and clause requirements, once to the SOC 2 Trust Services Criteria. The two audits remain separate, run by different parties under different rules, but you are not building two programmes. The incremental cost of adding the second framework is far lower than doing it cold, which is why sequencing them deliberately tends to beat treating them as unrelated projects.
A decision framework: usually sequence, not either/or
For most startups the useful question is not “which one” but “which one first”. A simple way to decide:
- Selling mainly into North America? Start with SOC 2, because that is what your buyers will ask for, and a Type 1 can give you something to show relatively quickly.
- Selling mainly into Europe or internationally? Start with ISO 27001, because it is the certification European procurement teams recognise.
- Selling into both, or planning to? Pick the framework your nearest-term deals demand, build the control set with the second framework in mind, then add it once the first is in place.
The trap to avoid is treating this as a permanent either/or. For a scaling SaaS company, the realistic end state is often both, and the question that actually saves money is the order you tackle them in and whether you design the underlying programme once.
How Atoro helps
Atoro is Europe’s first ISO 42001 certified consultancy, with more than 200 certifications delivered across security and compliance. We help startups decide which framework their buyers actually need, then build one control set that can carry both. We offer ISO 27001 implementation and SOC 2 implementation, scoped so that pursuing the second framework reuses the work behind the first.
ISO 27001 vs SOC 2 FAQs
Is ISO 27001 or SOC 2 better?
Neither is better in the abstract; they answer different buyer expectations. ISO 27001 is the more recognised certification in Europe and internationally, while SOC 2 is the default in North America. The right choice is driven by where your customers are and which one they ask for.
What is the main difference between ISO 27001 and SOC 2?
ISO 27001 is an international certification awarded by an accredited certification body, resulting in a pass or fail certificate. SOC 2 is an attestation report written by a licensed CPA firm against the AICPA Trust Services Criteria, describing your controls in detail rather than issuing a certificate.
Does SOC 2 cover ISO 27001?
No. Holding one does not grant the other, because they are issued under different rules by different parties. The underlying controls overlap heavily, so a single security programme can satisfy most of both, but each still requires its own separate audit.
Can you be certified to both ISO 27001 and SOC 2?
Yes, and many companies are. Because the ISO 27001 Annex A controls and the SOC 2 Trust Services Criteria overlap substantially, you can build one control set and map it to both frameworks, then run the two audits separately. The second framework costs far less to add than to start from scratch.
Which should a startup get first?
Start with whichever your nearest-term deals require. If you are selling mainly into North America, that is usually SOC 2; if you are selling into Europe or internationally, it is usually ISO 27001. Build the control set with the second framework in mind so you can add it later without redoing the work.
What is the difference between SOC 2 Type 1 and Type 2?
A SOC 2 Type 1 report assesses the design of your controls at a single point in time. A Type 2 report assesses how those controls operated over a defined period, so it takes longer because the auditor needs evidence spanning that window. Type 2 is the report most enterprise buyers eventually expect.
How much do ISO 27001 and SOC 2 cost?
There is no fixed price for either. Cost is driven by your organisation’s size, the systems in scope, how mature your existing controls are, the internal effort to close gaps, and the external auditor’s fees. The largest variable for both is usually internal time rather than the audit invoice itself.
Are ISO 27001 and SOC 2 recognised internationally?
ISO 27001 is an international standard and is the more widely recognised certification across Europe and globally. SOC 2 originated in the United States and is most common in North America, though it is increasingly seen elsewhere. Many buyers in each region prefer the framework native to their market.