SOC 2 vs ISO 27001: how to pick (and when to do both)

Two frameworks, two acronyms, one procurement questionnaire that asks for both. Most founders searching "SOC 2 vs ISO 27001" are not trying to learn the theory. They are trying to decide what to put on the security page this quarter without burning twelve months and a hundred thousand dollars on the wrong one.

Here is how we help our clients pick.

The one-sentence answer

If your buyers are in the United States, start with SOC 2. If your buyers are in Europe, the UK, Japan, or the Middle East, start with ISO 27001. If your pipeline has meaningful logos on both sides, plan to do both, and plan the evidence library so it feeds both audits from day one.

Everything below is the reasoning behind that sentence.

What each one actually is

The two frameworks look similar on a procurement spreadsheet and are structurally different under the hood.

SOC 2 is an attestation performed by a licensed CPA firm against the AICPA's Trust Services Criteria. The output is a report, signed by the auditor, that describes your system, lists your controls, and states whether those controls were suitably designed (Type I) or operating effectively over a period (Type II). There is no certificate. There is no logo. There is a PDF your buyer reads. Our what is SOC 2 primer covers the attestation from the ground up, and SOC 2 compliance requirements digs into the control set.

ISO 27001 is a certification against ISO/IEC 27001:2022, issued by an accredited certification body. The output is a one-page certificate saying your Information Security Management System conforms to the standard. The evidence lives in the CB's files, not yours. Your buyer sees the certificate, optionally plus a Statement of Applicability. For the plain- English version of the standard itself, see what is ISO 27001.

SecurancePro is a CPA firm. We perform SOC 1, SOC 2, and SOC 3 attestations, and we help companies get ready for ISO 27001. We do not issue ISO 27001 certificates. No single firm can be both your consultant and your certification body, and anybody who tells you otherwise is not accredited. For the full mechanics of the ISO side, see our ISO 27001 certification walkthrough.

Who asks for which

This is the part that decides the order.

US enterprise procurement has been trained on SOC 2 since the mid-2010s. When a Fortune 500 security team opens your vendor portal, they are looking for a SOC 2 Type II report and they know exactly which section they are flipping to.

European procurement, by contrast, was trained on ISO. DACH-region buyers, UK public sector, large Japanese enterprises, and most Middle Eastern regulated industries will list "ISO 27001 certification" as a hard requirement in the RFP. ISO reports over 70,000 valid ISO/IEC 27001 certificates across 150 countries as of the 2022 Survey, and that weight is what buyers in those markets are pattern-matching on. A SOC 2 report will often be accepted as supplementary evidence, but the checkbox says ISO.

The cross-over cases, the ones that push companies into doing both:

• A US SaaS selling into European subsidiaries of multinational buyers.
• A European company entering the US mid-market.
• Any company selling to regulated industries (banks, telcos, defense primes) in multiple regions.

If your pipeline is single-region for the next eighteen months, pick one. If it is not, assume both.

Effort and timeline side-by-side

The shape of the engagement is different in a way the sales cycle cares about.

SOC 2 Type II requires an observation window, typically six to twelve months, during which your controls have to be running and producing evidence. There are no "stages." The auditor does a readiness pass if you want one, then fieldwork at the end of the window, then a report. From a standing start, plan nine to fifteen months before you have a Type II report to hand a buyer. A Type I can be produced in roughly three months and is the usual placeholder.

ISO 27001 splits the initial audit into stage 1 (documentation review) and stage 2 (evidence audit), usually four to eight weeks apart. There is no twelve-month observation window in the same way, but the ISMS has to have been operating long enough to have at least one internal audit and one management review on the record, which is a floor of roughly three months in practice. Plan four to six months to the certificate.

Past the initial audit the cadences diverge again. SOC 2 is a fresh Type II every year, each one covering a new observation window. ISO 27001 is a three-year cycle: two surveillance audits in years 1 and 2, full recertification in year 3. A company in steady state has an annual SOC 2 engagement and an annual ISO engagement that alternates between surveillance and recertification.

Cost drivers

Ballpark numbers, for a growth-stage SaaS with one product and one environment.

• SOC 2 Type II audit fee: roughly $25k to $60k per year depending on firm, scope, and criteria selected.
• ISO 27001 initial (stage 1 + stage 2): roughly $20k to $50k, then $10k to $25k per surveillance year, then full recertification pricing in year 3.
• Readiness and consulting: the larger line item for most first-time companies. Budget two to three times the audit fee in the first year if you are building the program from scratch.
• Tooling: a compliance platform (Vanta, Drata, Secureframe, Tugboat, etc.) adds $15k to $50k per year and is optional, not required.

The trap is pricing the initial audit and forgetting the recurring line. ISO surveillance in year 1 is not free, and a SOC 2 Type II every year is a permanent engagement, not a one-off.

Where the two overlap

The reason doing both is cheaper than it looks: the controls overlap roughly 70 to 80%.

Access control, change management, encryption in transit and at rest, vulnerability management, incident response, vendor risk, logging and monitoring, HR security, business continuity, and secure development all appear in both frameworks under slightly different names. Build the evidence once, map it twice. The SOC 2 Trust Services Criteria map to ISO 27001 Annex A controls with enough fidelity that a well-run readiness project produces a single control register with two sets of labels. Our trust services criteria explained piece walks through the TSC side of that mapping.

The 20 to 30% that does not overlap is where the work is:

• ISO requires a formal ISMS, a risk methodology, a Statement of Applicability, an internal audit program, and a management review. SOC 2 does not.
• SOC 2 tests operating effectiveness over a window and lists exceptions by control. ISO certifies conformance with a management system and surfaces nonconformities against clauses.
• SOC 2 reports are private, shared under NDA. ISO certificates are public.

Build the evidence library once and map it twice. Running two programs with two document sets is how companies end up paying for the same control five times.

Three sequences that actually work

SOC 2 first, ISO 27001 second. The default for US-headquartered SaaS. Type I at month three, Type II at month twelve, ISO stage 1 shortly after the Type II closes, certificate by month eighteen. Works because the SOC 2 observation window forces the controls into real operation, and the ISMS documentation slots on top.

ISO 27001 first, SOC 2 second. The default for European companies expanding into the US. Stage 1 and stage 2 in months three and six, SOC 2 Type I immediately after (reusing the ISMS controls), Type II the following year. Works because the ISMS gives you a control library that SOC 2 can test directly.

Parallel programs from day one. The right choice when the pipeline already has buyers on both sides and you have the internal bandwidth. Kickoff a single readiness project, build one control register with dual labels, engage a CPA firm for SOC 2 and an accredited certification body for ISO. Expect to be done with both in twelve to fifteen months. Cheaper than doing them in series with different vendors, more expensive than picking one.

When to just pick one

If you are a seed or Series A company with a single-region pipeline and a runway that does not stretch to two audits, pick the one your next three buyers will ask for and ignore the other. Your future self can add the second framework once the first is producing revenue. Shipping a good SOC 2 or a good ISO 27001 beats shipping a thin version of both.

If you are planning a SOC 2, an ISO 27001 readiness, or a combined program and want a CPA firm's read on the sequence, see our services or get in touch.