Translate Chinese manuals and technical documents to English

Author: Yuri Vodostoy — Technical translator and founder of Insight Translation · Updated 2026-10-16

Upload a Chinese manual, datasheet, or standard as DOCX, XLSX, PPTX, text-layer PDF, or XLIFF, choose English, and download an English translation for review. A glossary lets you specify the terms your project uses. Our test source was the chapter on welding, testing, and heat treatment in TSG 21—2016, China's national regulation on stationary pressure vessels. Google Translate kept every number and every prohibition, but alternated between two names for the manufacturer and between "shall" and "must" for the same Chinese requirement word.

Is Google Translate enough for a Chinese technical document?

Google's translation was enough for an initial reading of this chapter: all 77 numbers came out unchanged, and its prohibitions stayed prohibitions. A QA engineer checking a weld or a buyer quoting the English to a supplier also needs consistent terminology and requirement wording. Those checks span the document and are easy to miss when reading one sentence at a time.

How Google handled shall and must

Google used both "shall" and "must" to translate 应当, including within a single sentence. The Chinese source uses both 应当 and 必须 to express obligations. The ISO/IEC drafting rules for standards use "shall" for a document's requirements and "must" for external constraints. This is an English drafting convention for ISO/IEC documents; it does not determine the legal force of a Chinese regulation or require a fixed English verb for each Chinese expression. The heat-treatment procedures clause in TSG 21—2016 contains two instances of 应当:

Tested October 6, 2026, Chinese to English. Across the whole chapter, the source uses 必须 only twice. Google wrote "must" 11 times, at least five of them where the source says 应当. HardTrans used "shall" in every paragraph containing 应当 and "must" for the two clauses with 必须. Without a glossary, it used "must" once more, for a condition that has to match. Both English verbs express an obligation; the inconsistency here is in the wording.

Google preserved the recommendation, permission, and ban (宜, 可, 不得) in the clause on furnaces for nickel-alloy vessels: "Electric furnaces are preferred", "may also be used", "are prohibited". All eight bans (不得) in the chapter remained bans in English.

Term consistency across the chapter

Google alternated between terms for the manufacturer, pressure parts, and shells. HardTrans also alternated between "shell" and "cylinder" without a glossary. The counts cover the full chapter, with singular and plural counted as one form. English mentions need not equal source occurrences: the Google column counts explicit forms in its full translation, where sentences were sometimes joined or recast.

Google's "manufacturing unit" is a word-for-word rendering of 制造单位. Its use of "manufacturer" elsewhere for the same Chinese term can leave a reader unsure whether the regulation means one party or two.

What a glossary changes, and what it does not

HardTrans without a glossary switched from "shell" to "cylinders" inside two clauses about testing shells, with more occurrences of "cylinder" than Google. A 21-term glossary kept the wording consistent in the clause below:

With the glossary, 筒体 came out as "shell" in all ten places. We also used it to choose between valid English terms. For 受压元件 we chose "pressure-bearing part", the wording of the EU Pressure Equipment Directive. HardTrans's default, "pressure-retaining component", is also correct and appeared in all nine places without a glossary. For 母材 we chose "parent metal" over "base metal"; both are standard. These choices specify the wording for a project. They do not guarantee that every term will stay consistent; HardTrans still used some abbreviations.

For pressure vessel, head, annealing, pressure test, chemical composition, and mechanical properties, the glossary changed nothing: HardTrans already used those terms consistently. Both runs preserved the source numerical values.

Why Chinese technical text is hard for machine translation

Chinese technical clauses can omit a subject supplied by a heading. Clause (1) under "Surface quality of welded joints" reads 不得有表面裂纹… ("must not have surface cracks…") with no subject. HardTrans brought "welded joints" back from the heading: "Welded joints shall not have surface cracks". Google rebuilt the sentence as "Defects such as surface cracks… are not permitted". Both readings are correct; the heading supplies the context missing from the clause.

Short expressions such as 应当, 宜, and 可 distinguish obligations, recommendations, and permissions. In English, these can be expressed as "shall", "should", and "may". Losing that distinction changes what an inspector can demand.

Chinese words are not separated by spaces. 焊后热处理 (post-weld heat treatment) contains 热处理 (heat treatment) as part of a longer term. Splitting the string in the wrong place can turn a specific requirement into a general one.

Where HardTrans fell short

Without a glossary, HardTrans shortened terms the source spells out in full: "100% UT", "partial NDT". Both are standard abbreviations, but a document that defines neither may not pass a client's style check. With the glossary, it wrote "non-destructive testing" in 19 of 24 places and kept NDT in the rest.

In two clauses, HardTrans with the glossary rendered the permission 可 as "only the outer surface need be tested" instead of using "may". The meaning is right, but a search for "may" will miss those two permissions.

Price and formats

$1.50 per page of 250 words. The first document up to 10 pages is free, so a chapter like the one in this test costs nothing to try. Supported files: DOCX, XLSX, PPTX, PDF with a text layer, and XLIFF from CAT tools. Scans and photographed pages are not supported yet. See also our XLIFF guide and more Google Translate vs HardTrans examples.

Method

On October 6, 2026, we translated one chapter of TSG 21—2016, the Chinese safety regulation for stationary pressure vessels: 69 paragraphs, about eight pages. We used Google's public text window on the same day. HardTrans translated the same text as a Word file, once without a glossary and once with a 21-term glossary checked against published standards and regulations before the run. We then counted, over the full chapter, every English form used for each key term, every requirement word, and every number. Google's counts are over the whole text, because its text window joined some short lines. We did not test Google's document upload.

Frequently asked questions

Can I translate a Chinese PDF manual to English? Yes, if the PDF has a text layer (you can select the text in a viewer). Scanned pages and photos are not supported yet.

Will the numbers stay the same? All source numerical values survived in both Google's and HardTrans's translations in this test. Without an uploaded glossary, HardTrans also expressed 全部 ("all" or "in full") as "100% NDT", so its set of digits was not literally identical to the source. Check tolerances and limits against the source before you sign off.

Do I need a glossary? Without a glossary, HardTrans held one form for most terms in this chapter, but alternated between "shell" and "cylinder". Use a glossary to specify the terms your client or standard requires, then check the result.

What if my client uses ASME terms rather than European ones? Put the ASME terms in the glossary. In this test we chose the European wording, but "base metal" and "pressure-retaining component" are equally correct.

Is this a certified translation? No. HardTrans produces a working translation for engineers and reviewers. For submissions that require a certified translator, use it as a draft for that translator.

Upload your Chinese document. The first document up to 10 pages is free. Questions: [email protected].