ISO 27001 vs SOC 2: a practical comparison

ISO 27001 and SOC 2 are the two most common information-security assurance programmes for tech companies. Here is how they differ in scope, audit process and cost — and how to choose.

What they are, in one sentence each

ISO 27001 is an international certifiable standard that requires an Information Security Management System (ISMS), a risk assessment, a set of controls (Annex A) and continuous improvement — audited in two stages by an accredited certification body.

SOC 2 is a US-originated attestation report issued by a CPA firm. It describes how your service organisation meets the AICPA Trust Services Criteria (Security, Availability, Confidentiality, Processing Integrity and Privacy) over a defined period.

In the real world, both answer the same buyer question: "Is our data safe with you?" The difference is geography, format and the level of structural discipline required.

Scope: what each programme covers

Step 1

ISO 27001 — full ISMS scope

ISO 27001 demands a complete management system: context of the organisation, leadership commitment, risk assessment, risk treatment plan, Annex A controls, operation, performance evaluation and improvement. The certificate covers the entire ISMS scope statement — usually all IT systems, offices and personnel that handle customer data.

Step 2

SOC 2 — scoped by TSC and system description

SOC 2 scope is narrower and self-defined. You choose which Trust Services Criteria apply (Security is mandatory; the rest are optional), write a system description that bounds the audit, and the auditor tests only within that boundary. Most SaaS companies start with Security + Availability + Confidentiality.

Bottom line: ISO 27001 is broader and more prescriptive about the management system itself. SOC 2 is more flexible on scope but deeper on continuous operational testing over time.

Audit process: how each one works

Step 1

ISO 27001 — two-stage certification audit

Stage 1 (documentation review): the auditor checks your ISMS documentation, risk assessment, statement of applicability and policies. Usually remote, 1–2 days.
Stage 2 (evidence and implementation): the auditor interviews staff, inspects systems and reviews records to confirm the ISMS is actually operating. Usually on-site or remote, 2–4 days.
Recertification happens every three years with annual surveillance audits.

Step 2

SOC 2 — Type I then Type II

Type I: a point-in-time audit. The auditor reviews the system description and tests that controls are designed appropriately. 2–4 weeks of auditor time.
Type II: covers a period (3–12 months). The auditor tests that controls operated effectively throughout the window, sampling evidence such as access reviews, ticket closures and backup logs.
Most SaaS companies do Type I first, then Type II in the following year.

Cost comparison

Figures vary by firm, geography and company size, but for a 50-person SaaS company the typical range is:

ISO 27001 certification: £12k–25k for the initial two-stage audit, plus consultant or internal time to build the ISMS (80–150 hours). Annual surveillance: £4k–8k.
SOC 2 Type I: £8k–18k for the audit, plus readiness work (40–80 hours). Type II adds £10k–20k depending on the observation period.
Both together: roughly 1.3× the cost of one, not 2×, because the risk register, policies and evidence library are shared.

Hidden costs to budget for: penetration testing, vulnerability scanning, background checks, security-awareness training and policy-writing time. These are required by both programmes.

Which should you choose?

Choose SOC 2 first if your primary market is North American enterprise, your customers ask for a Type II report, and you need the fastest path to a recognised assurance document.
Choose ISO 27001 first if you sell internationally, bid for public-sector or regulated contracts, or your leadership prefers a certifiable standard with a clear three-year recertification cycle.
Do both together if you have global enterprise customers, if your competitors hold both, or if you want to avoid answering the "what about ISO 27001?" question six months after finishing SOC 2.

Control overlap: why running both is easier than it looks

The Annex A controls in ISO 27001 map almost one-to-one to the Common Criteria in SOC 2 Security. Access control, cryptography, physical security, operations security, supplier relationships, incident management and business continuity appear in both. The difference is largely in how you demonstrate compliance:

ISO 27001 wants documented procedures, risk treatment records and management-review minutes.
SOC 2 wants sampled evidence that controls operated over time — screenshots, tickets, logs and approvals.

A good compliance platform stores both types of evidence in one place, linked to the same control, so you never write a policy twice or hunt for the same log twice.

Run ISO 27001 and SOC 2 from one workspace

ISO-STANDARD.app keeps your risk register, Annex A controls, SOC 2 Trust Services Criteria mapping, policies and audit evidence in a single system. No duplicate spreadsheets, no consultant lock-in, no surprise gaps when the auditor arrives.

ISO-STANDARD.app ships a ready-to-adopt ISO 27001 / SOC 2 workspace with the risk register, controls catalogue, policies and audit-ready exports already wired together — no spreadsheet sprawl, no consultant lock-in.

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Prefer a conversation? Email hello@iso-standard.app — a real human responds within one business day.

Frequently asked questions

Can we do ISO 27001 and SOC 2 at the same time?

Yes — and most fast-growing SaaS companies should. The control overlap is roughly 70 %. A single risk register, policy set and evidence library can feed both programmes, cutting total effort to about 1.3× instead of 2×.

Which is more recognised — ISO 27001 or SOC 2?

ISO 27001 is the global standard; SOC 2 dominates North America. If you sell to enterprise buyers in the US, SOC 2 Type II is usually table stakes. If you sell internationally or bid for public-sector work, ISO 27001 is often required.

Is SOC 2 a certification?

No — SOC 2 is an attestation report issued by a CPA firm. ISO 27001 is a certifiable standard issued by an accredited certification body. In practice, both satisfy the same customer question: 'can we trust you with our data?'

How long does each take from zero?

ISO 27001: 4–6 months for a first certification, including stage 1 and stage 2 audits. SOC 2 Type I: 2–3 months. SOC 2 Type II: add the observation window (3–12 months) on top.

Which is cheaper — ISO 27001 or SOC 2?

SOC 2 Type I is usually cheaper upfront because the scope is narrower and the audit is shorter. ISO 27001 has higher initial cost (full ISMS build + two-stage audit) but lower ongoing marginal cost if you later add SOC 2, because the policy and risk infrastructure is already in place.

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