Contract Translation Services for International Businesses

Cross-border commerce runs on contracts that hold up in every jurisdiction they touch. Contract translation is the specialised subset of our wider Translation Services in London and the UK that converts commercial agreements between English and 200+ languages under ISO 17100, with certified, sworn, notarised or apostille attestation calibrated to the receiving authority.

Which certification tier does an international contract need?

An international contract needs one of four attestation tiers: certified translation for most B2B counterparties, sworn translation for civil-law jurisdictions such as Spain or France, notarised translation for corporate registries and banks, and apostille for public-document use under the 1961 Hague Convention. The wrong tier voids enforceability abroad, so tier selection is confirmed in writing before translation begins.

When is a certified translation enough for a commercial contract?

A certified translation is enough when the counterparty, court or regulator accepts a signed statement of accuracy from an ISO 17100 language service provider, which covers most UK, US, Irish, Australian and Canadian commercial dealings. The certificate names the linguist, the language pair, the source document and the ISO 17100 workflow applied. Full scope, tier definitions and turnaround for this attestation tier sit on our Online Certified Translation Services in the UK page.

When is a sworn or notarised translation required?

A sworn or notarised translation is required when a civil-law jurisdiction, corporate registry, notary public or embassy specifies it — for contracts filed in Spain, France, Germany, Italy, Poland, Brazil, Mexico and much of Latin America. In many EU member states, sworn translators are appointed directly by a court or ministry of justice, and only their sealed translation is admissible before public authorities. A notarised translation, by contrast, is one where a notary public attests to the identity of the signing translator — the notary does not verify translation accuracy, only that the translator swore to it.

When does a translated contract need an apostille?

A translated contract needs an apostille when it accompanies a public document — such as a notarised power of attorney or a company incorporation certificate — used in a Hague Convention country. The Hague Apostille Convention of 5 October 1961 now covers more than 120 signatory states, and the apostille replaces the older embassy legalisation chain (see the HCCH Apostille Convention text). Non-Hague destinations still require full consular legalisation.

How fast can a business contract be translated?

A business contract is translated same-day for civil documents under 1,000 words ordered in London before 11:00 GMT, within 24 to 48 hours for standard legal and academic packs, and on agreed milestones for contracts above 10,000 words, all under ISO 17100 quality control.

What is the 11:00 GMT same-day cut-off?

The 11:00 GMT same-day cut-off means any contract under 1,000 source words placed in London before 11:00 GMT on a working day is delivered the same day, subject to the requested certification tier being certified rather than sworn. Sworn work involves a court-appointed linguist’s calendar and moves to a 48–72 hour SLA. Files arriving after 11:00 GMT roll to the next working day’s same-day queue.

How are long contracts and M&A data rooms scheduled?

Long contracts and M&A data rooms are scheduled on milestone delivery: batches of related documents are released every 48 to 72 hours against a signed statement of work, with terminology locked in a shared glossary from milestone one. The milestone approach lets deal counsel review the SPA in parallel with the disclosure letter, ancillary documents and employment schedules without waiting for the full pack.

How are bilingual and ‘governing language’ clauses handled?

Bilingual and governing-language clauses are handled by preserving the original English drafting as the prevailing version and translating the second language as a reference version, unless the parties instruct otherwise in a written brief. The prevailing-language instruction is confirmed at quote stage so the linguist knows which text carries authority.

What is a ‘prevailing version’ clause?

A prevailing version clause states which language controls interpretation if the two translations diverge, and it is drafted before translation begins so the linguist knows which text is authoritative. Standard English-law drafting keeps English as the prevailing version; the translated language sits alongside for local counterparty comprehension, filing or regulatory purposes.

How are defined terms kept consistent across languages?

Defined terms are kept consistent through a locked bilingual glossary built in the first 200 source words and applied by CAT tools across every clause, appendix and side letter in the contract set. Translation memory reuses previously approved renderings of terms like “Affiliate”, “Business Day”, “Change of Control” and “Material Adverse Effect”, which both stabilises meaning and reduces cost on repetitive clauses.

What quality standard governs the translation?

Contract translations are governed by ISO 17100, the international standard for translation services that mandates qualified translators, an independent reviser, defined project management and traceable revision records. ISO 17100:2015 is the recognised global benchmark for translation-service quality and defines the workflow, resource qualifications and revision requirements binding on every project (see the ISO 17100 standard entry). The same standard underpins every service across our Professional Translation Services in the UK.

What does ISO 17100 require on every project?

ISO 17100 requires four things on every project:

1. A qualified translator with legal-domain competence and evidenced credentials.
2. An independent reviser — a second linguist — performing a bilingual comparison of source and target.
3. A documented project manager owning scope, timeline and client communication.
4. A corrective-action record retained for audit, capturing any post-delivery amendment.

Raw machine translation is not accepted for binding contracts; where MT is used at all, it is followed by full human post-editing by a legal-domain linguist and then by the ISO 17100 revision step.

How do I brief a contract translation project correctly?

Brief a contract translation project correctly by supplying five inputs at the point of instruction. A complete brief is the single most effective way to compress turnaround time: every missing field is a delay, because the project manager must pause intake to resolve ambiguities before assigning a linguist or opening a confidentiality agreement. Providing all five inputs up front means a quote in GBP, a confirmed ISO 17100 SLA, a signed linguist NDA, and a locked glossary are all in place within one working hour of receipt.

1. The editable source file — Word is preferred; a clean, text-layer PDF is acceptable. Scanned images require OCR preparation and extend the intake time, so editable formats should be used wherever the original permits.
2. The target jurisdiction and language variant — jurisdiction determines which legal system the translation must speak to, and variant selection (for example, European Portuguese versus Brazilian Portuguese, or Castilian versus Latin American Spanish) is mandatory because bilingual contracts must name the exact variant in the governing-language clause.
3. The required certification tier — the four tiers are certified, sworn, notarised, and apostille. Apostille authentication is governed by the 1961 Hague Convention and is required when a public document — including a notarised translation — must be recognised in another signatory state. Knowing the tier at brief stage allows us to allocate the correct linguist credentials and any notarial or apostille processing time within the quoted SLA.
4. The prevailing-language instruction for bilingual execution — where a contract will be executed in two languages, the governing version must be specified before translation begins. This clause controls which text prevails in the event of a dispute, and it directly shapes how ambiguous source passages are rendered in the target language.
5. The signing deadline in GMT, plus any foreign-registry filing deadline — deadlines must be stated in GMT. For instructions under 1,000 words, same-day delivery is available for briefs received by 11:00 GMT; for standard legal packs, the turnaround is 24–48 hours; for projects exceeding 10,000 words, milestone delivery is scheduled so that the client’s legal team begins review in parallel.

All project data is handled under a written data-processing agreement in which we act as data processor under UK GDPR. Files are held in a segregated, access-controlled environment, transferred via TLS or SFTP, and destroyed within 30 days of delivery unless a longer retention period is expressly agreed.