ISO 18587 Certification: Is It Worth It for a Small Translation Agency?

ISO 18587:2017 sets requirements for full, human post-editing of machine translation output and for post-editors' competences. For a small agency, certification is worth it only when clients or tenders ask for it, or when your post-editing volume is large enough that audited processes would reduce rework. Otherwise document the process first and certify later.

Pages that rank for this keyword describe the standard and the benefits. They do not tell a six-person agency what the decision costs, what evidence an auditor wants to see, or how to test whether the certificate will earn its keep. Treat it as a purchase instead: define what you buy, estimate the cost, and compare it with what clients are actually asking for.

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What the standard covers, and what it does not

The published scope line is short. ISO 18587:2017 gives requirements for the process of full, human post-editing of machine translation output, plus the competences post-editors need. It applies to material that has been produced by a machine translation system, and for translation services in general it points to ISO 17100. It was published in April 2017 and runs to 15 pages. As of October 2026, ISO's catalogue page lists it as "to be revised" and expects it to be replaced within months by a draft, ISO/DIS 18587, retitled "Post-editing of non-human translation output". That title is broader than machine translation, but a draft can still change, so read the final text before assuming what it covers, and ask which edition your certification body audits against and how it handles the switch.

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Two consequences follow. First, the scope names full post-editing, meaning output meant to be comparable in quality to a human translation. Some certifier pages also describe a "light" level, with a lower quality target for internal or gist use. The standard's scope line does not mention light post-editing, so ask any certification body in writing whether light work falls inside your certificate's scope. Second, the standard is about the process and the people, not the engine. DeepL, a general AI model or an engine inside a translation tool are all just sources of machine output.

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The requirements, in outline

I could not read the full text of the standard, which ISO sells, so what follows is the outline that certification bodies publish. Treat it as a map and buy the standard before you plan.

The row on engines matters more now that many agencies use general AI models. An auditor will want to see why you chose an engine, how you tested it, and what happens to client text when it is sent there. The tutorial on choosing DeepL or ChatGPT for each document type shows a way to run the test.

How it relates to ISO 17100

ISO 17100 covers translation services in general: translator qualifications, project management, revision by a second person, and the core service. As certification bodies summarise it, a translator qualifies through one of three routes: a degree in translation, linguistics or language studies that includes significant translation training; a degree in another field plus two years of full-time translating; or five years of full-time translating. ISO 18587 builds on that by adding what is specific to post-editing: the knowledge of machine translation and the process steps around the engine output.

In practice there are three positions an agency can be in.

1. You already hold ISO 17100. Much of the competence, project and revision paperwork exists. The new work is engine evaluation, post-editing agreements and a post-editing procedure.
2. You hold neither. The first-year work includes building the whole quality system. TranslationCert's FAQ says you can certify to ISO 18587 on its own, but you will end up writing most of what ISO 17100 asks for.
3. You hold something else, such as ISO 9001 or ISO 27001. Management-system habits (document control, corrective action, internal audit) transfer; translation-specific competence rules do not.

If you must choose one, check which standard your clients' procurement forms actually name before you pay for 18587. ISO 17100 is the broader translation-services standard, so a form that asks only for it will not be answered by an 18587 certificate.

What the audit involves, step by step

Certification bodies describe a similar path. The outline below combines what two certifiers publish; your body's exact steps and timings will differ, so ask for them in a quote.

1. Gap check. Compare your current post-editing workflow with the requirements. Some bodies offer a free readiness check.
2. Documentation. Write or adapt procedures, competence records, the client-agreement template and the engine-evaluation record.
3. Run it for a while. Auditors want samples of real projects handled under the procedure, so you need completed jobs, not just documents.
4. Internal review. Check your own records against the standard before the auditor does.
5. Audit. The body reviews post-editor records, sample projects, engine evaluations and client agreements. Some audits run remotely.
6. Certificate and surveillance. One certifier states a three-year validity with annual surveillance audits, which is common for management-system certificates. Confirm for yours, because each surveillance visit is a recurring cost.

A competence record, filled in

This is the document small agencies find hardest, because the freelancers are not employees. A usable one-line-per-person record looks like this (illustrative).

Post-editor: [name]   Language pair: EN to DE
Qualification route: degree in another field + 3 years full-time
  translation experience (evidence: CV, two client references)
MT knowledge: 2-hour internal briefing 12 Sep; 40 sample segments
  post-edited and reviewed by senior editor 19 Sep
Domains approved: software UI, marketing (not legal, not medical)
Reviewed: 4 Nov by quality lead. Next review: Nov next year.

Notice the domains line. If a freelancer is approved for software and marketing only, the system must stop a legal job going to them. That restriction, enforced by your project manager, is what an auditor tests with a sample job.

The cost side: what you would pay, and no invented prices

I could not find public price lists from the certification bodies I checked; they quote on request, and fees depend on staff numbers, sites and the body. So the figures below are a structure, not a quote. Ask two or three bodies for a written quote covering the first audit, the certificate, annual surveillance and re-certification at the end of the cycle.

The last line is the one agencies forget. Evidence per job (engine note, agreement, revision record) costs a few minutes every time. A tool that attaches these to the project file keeps it small; see what a small agency needs from an AI-powered translation management system.

A break-even test with your own numbers

Here is the test, with an illustration. A six-person agency with ten regular freelancers earns about $480,000 a year. Post-editing work is 25 per cent of revenue, or $120,000. Assume, for illustration only, that the first-year total cost of certification, counting audit fees, consultant help and about 120 hours of staff time at $45 an hour, comes to $9,000, and that years two and three cost $3,000 a year in surveillance and upkeep. That is $15,000 over a three-year cycle, or $5,000 a year on average.

To cover $5,000 a year, certification must produce about $5,000 of extra gross margin. If your margin on post-editing is 35 per cent, you need about $14,300 of additional post-editing revenue a year, which is roughly 12 per cent growth in that line. Alternatively, if certification wins one client who spends $20,000 a year on post-editing at 35 per cent, the margin is $7,000 and it pays for itself in the first year of that account.

Replace each figure with yours, then answer three questions in this order.

1. Has a client or tender asked for it? Count the requests in the last 12 months. Zero requests and a break-even of 12 per cent growth is a weak case. Two lost tenders that named it is a strong one.
2. Which prospects would buy because of it? Name them. "Enterprises adopting MT", in a certifier's brochure, is not a prospect.
3. What else would the same $15,000 buy? A paid engine upgrade, a TMS, or a part-time quality lead may produce more margin.

Three agencies, three outcomes

These are illustrations, not case studies.

• The agency whose clients asked. A life-sciences agency loses two tenders because a questionnaire asks for "post-editing process certified to ISO 18587 or equivalent". It already follows ISO 17100. Certification is a short extension and a direct sales tool. Verdict: worth it.
• The agency that runs MT for marketing copy. Most clients are small businesses buying on price and speed, and none have mentioned a standard. The work is mainly light touch. Verdict: not yet. Write the process down, record engine evaluations and show clients the documented workflow.
• The agency about to bid for a big framework. The framework document lists ISO 17100 as mandatory and ISO 18587 as an advantage for scoring. Verdict: ISO 17100 first, 18587 as a scoring top-up if the extra points matter.

The cheaper route: build the process, skip the certificate for now

Most of the benefit of the standard comes from having the process, not from the certificate. You can adopt the practical parts in a month with no audit fee: a client-agreement line that fixes the post-editing level, an engine test log, a post-editor competence record, a revision step and a short delivery checklist.

An agreement line and an engine log, filled in

Service level agreed (project 2411-07): FULL post-editing of machine
translation output. Intended use: published website text. Target:
quality comparable to a human translation. Glossary: supplied, v3.
Style guide: client's. Revision: second linguist, included.
Engine: general AI model, tested 4 Nov on 40 sample segments.
Result: 31 correct, 6 minor edits, 3 terminology errors. Decision:
suitable with glossary supplied in the prompt. Tested by: [initials].

That is two short records per job, and they answer most of what a buyer's questionnaire asks. The workflow behind them is described in a translator's post-editing workflow and in building an AI-assisted workflow for a small agency.

If you later certify, those records are exactly the evidence an auditor samples. If you never do, you have a defensible, documented process to show clients. Either way the work is not wasted.

A questionnaire answer, before and after

Client security and quality questionnaires are where the gap shows. A weak answer reads: "We use machine translation with human checking." A stronger, truthful one reads: "We post-edit machine translation to a full-post-editing standard. Each job records the agreed post-editing level, the engine test result and the revision by a second linguist. Our process is designed around ISO 18587 but is not certified. Records available on request." The second answer is longer, honest, and gives a procurement reader something to verify.

Pricing post-editing so the standard's extra steps are paid for

Certification adds steps: an engine test, an agreement, a revision. If your per-word rate was set before those steps existed, they come out of your margin. The tutorial on post-editing rates per word covers the market question; here is the internal sum. Say a typical 5,000-word job takes a post-editor 10 hours at a cost of $35 an hour, and the extra records and revision add 1.5 hours of staff time at $45. The extra cost is $67.50 on a job worth, say, $750, about nine per cent of the price. If you cannot recover that through a modest premium or a faster turnaround, the certificate will lower your margin even while it raises your credibility.

Some agencies fold the cost in quietly and some state "documented post-editing process" as a line on the quote. Test it on two clients and see whether anyone objects. A client who needs the assurance will not.

Using AI models as the engine: what an auditor will ask

General AI models behave differently from classic translation engines, and the questions change slightly. They can follow a glossary and a style note inside the prompt, which helps terminology, but the same prompt run twice can give different wording. An auditor reading your engine record will want to see that you noticed this. Here is a short illustrative test record for a general model used on a product-manual job.

Engine test, project 2411-12 (EN to FR, product manual)
Prompt: glossary of 28 terms, instruction "do not translate part numbers"
Run 1 and run 2 on the same 30 segments:
  Identical output: 19 segments
  Different wording, same meaning: 9
  Different meaning: 2 (torque unit; "left" vs "port side")
Decision: usable for full post-editing with glossary and a unit check
by the editor. Not usable unsegmented, whole-document, without review.

That record shows judgement. It also tells the post-editor exactly where to look. If you use a general model, confirm the plan's data terms: business plans of the main assistants list no training on your content by default, while personal plans may not, and a client's confidentiality clause may prohibit sending text to a third party at all. That is a conversation to have with the client before the project, and it is the kind of record the confidentiality row of the audit expects.

What to ask a certification body before you sign

• Which accreditation do you hold, and for which standards? Can I see the scope on your accreditation certificate?
• Which edition of ISO 18587 do you audit against, and what happens when the revision is published?
• Does my certificate cover full post-editing only, or also lighter levels?
• How many audit days do you assume for my headcount and number of freelancers?
• Is the audit remote, on site or both, and what is included in the fee?
• What are the surveillance fees and the re-certification fee at the end of the cycle?
• Are freelancers' records audited individually or by sample?
• What happens if a major non-conformity is raised, and how long do I have to fix it?

Put the answers from two or three bodies in one table, side by side with the quoted fees. The decision usually becomes clear when the recurring costs are visible next to the revenue you expect from clients who ask for it.

Mistakes agencies make with this standard

• Claiming certification you do not hold. A website line such as "ISO 18587 compliant" on the strength of a consultant's gap check is a misleading claim. A reader will understand it as certified.
• Certifying the wrong thing. A certificate that covers translation but not post-editing, or one scoped to a single office, will not answer a questionnaire that asks about MTPE.
• Buying an unaccredited certificate. Ask whether the body is accredited and ask a prospective client which certificates it accepts before you pay.
• Letting the paperwork outrun the practice. Freelancers handle jobs differently from the written procedure, and the auditor samples a real project. Run the procedure for a few months first.
• Ignoring data terms of the engine. An engine whose terms allow training on your clients' text breaks a confidentiality promise whatever the certificate says. Check each vendor's plan terms and security certificates before the first client file goes in.
• Treating AI output as pre-approved. A fluent AI translation is not evidence of accuracy. The standard exists because fluent output can hide errors.

Deciding in an afternoon

1. Count requests. Search your last year's tenders, questionnaires and lost-deal notes for "ISO", "post-editing" and "MTPE".
2. Estimate post-editing revenue and margin. Use the break-even calculation above.
3. Request two quotes from accredited bodies, naming the scope (post-editing service, languages, sites) and the cycle costs.
4. Start the cheap route. Put the agreement line, engine log and competence record into use on new jobs this month.
5. Set a trigger. Decide in advance: "If two clients or one framework ask in the next six months, we certify." Write it down and review in six months.

If you want to go through your own numbers and workflow with someone, that is what my AI implementation consultation covers. A related first step for agencies that have not yet decided how to combine engine output with existing assets is combining translation memory and AI.

Questions agencies ask about ISO 18587

Does ISO itself certify my agency?

No. ISO writes the standard; independent certification bodies audit you and issue the certificate. Ask any body you consider who accredits it, because an unaccredited certificate may carry less weight with procurement teams. Your clients' tender documents usually say what they accept.

Do I need ISO 17100 first?

Not formally. TranslationCert's published FAQ says ISO 18587 can be certified on its own, but ISO 18587 points to ISO 17100 for translation services in general and for translator competence. An agency that already runs to ISO 17100 has much of the paperwork done, so the second certificate costs less effort.

Does the standard cover ChatGPT or DeepL output?

The 2017 edition concerns the post-editing process and the post-editor, applied to content processed by machine translation systems, and does not name engines. The draft revision is retitled for non-human translation output in general. If you use a general AI model as your engine, your engine-evaluation records should show how you tested it for each language pair and content type.

Can I say we follow ISO 18587 without certifying?

You can describe your process truthfully, for example 'our post-editing workflow is designed around ISO 18587'. Do not say 'certified', 'compliant' or 'accredited' unless an audit body has issued a certificate that covers the service and the scope you describe.

Further reads

• AI Translation vs Human Translators: What Documents Really Cost — What documents really cost by method.
• Does Your Translation Business Need an AI Usage Policy? — Write the AI usage policy auditors expect.
• Is It Safe to Put Client Documents Into AI Translation Tools? — Whether client documents are safe in AI translation tools.
• Is Machine Translation Good Enough for Client-Facing Documents? — When machine translation is good enough for clients.
• memoQ vs Trados for Small Translation Agencies: AI Features and Cost — Tool choice for a small agency, with AI features.
• How to Check AI Translations Before Customers See Them — A quick check routine before customers see output.
• SOC 2 and ISO 27001 Explained: Checking an AI Vendor's Security — Check an AI engine vendor's security certificates.
• AI Tools and AI Development: The Complete 2026 Guide — the AI hub, including every tutorial in the AI-for-business series.

Sources: ISO catalogue page for ISO 18587:2017 (archived copy, 10 October 2026), TranslationCert ISO 18587 and ISO 17100 pages, USQC ISO 18587 page (checked 4 November 2026). No certification price list was available, so no fees are quoted.