In this guide · 8 sections
- 01What the benchmarks show for English-Chinese translation
- 02What about the newest 2026 models?
- 03Where AI translation still goes wrong in business documents
- 04Choosing a tool: data terms and workflow matter more than scores
- 05How to run your own 30-minute translation test
- 06A human-review rule for Chinese-English translation
- 07Do it yourself or get help?
- 08Frequently asked questions
Short answer
In the latest human-graded benchmark, WMT25 English-to-Chinese, Claude 4, DeepSeek V3, GPT-4.1 and Gemini 2.5 Pro all scored within about 3 points, above the human reference. Any leading model drafts well; choose on data terms and workflow, and have a fluent person check customer-facing or legal text.
What the benchmarks show for English-Chinese translation
The most useful independent evidence is the annual WMT machine translation evaluation, where professional annotators grade full documents. The WMT25 findings (published November 2025) included English to Simplified Chinese, with Microsoft annotators who are bilingual native speakers or professional translators.
| System (WMT25, English to Chinese) | Human score | Rank cluster | Type |
|---|---|---|---|
| Algharb | 88.4 | 1 | Research system (fine-tuned Qwen3 14B) |
| Shy-hunyuan-MT | 88.2 | 2-4 | Research system |
| Claude 4 | 86.9 | 2-5 | General LLM |
| DeepSeek V3 | 85.0 | 3-6 | General LLM |
| GPT-4.1 | 84.0 | 5-10 | General LLM |
| Qwen3 235B | 84.0 | 6-11 | General LLM |
| Gemini 2.5 Pro | 83.8 | 6-11 | General LLM |
| Human reference translation | 82.1 | 11-13 | Professional translation |
Two points matter for a business. First, the leading general models are close together, and all were graded above the human reference on this test set. Second, WMT25 tested English to Chinese, not Chinese to English, and used 2025 model versions.
What about the newest 2026 models?
Model names change faster than benchmarks. As of October 2026 the current flagships are Claude Opus 5.5, GPT-6 Astra and GPT-6.1 Sol, and Gemini 4 Argon, all released in September 2026 according to Artificial Analysis. None has yet been through a published, human-graded English-Chinese translation evaluation.
Artificial Analysis also runs a Multilingual Index that includes Chinese, but it measures reasoning in each language rather than translation, and when we checked on 18 October 2026 its Chinese results still listed earlier models, with Claude Opus 4.6 and Gemini 3.1 Pro Preview both scoring 94. Singapore's own SEA-HELM leaderboard covers Burmese, Filipino, Indonesian, Malay, Tamil, Thai and Vietnamese, not Chinese.
Where AI translation still goes wrong in business documents
High benchmark scores hide the errors that matter most to a business, because a single wrong number or name outweighs a hundred fluent sentences.
| Risk | Example | How to reduce it |
|---|---|---|
| Names of people and companies | A director's Chinese name rendered three ways in one document | Give a name list; ask for names to be left as given |
| Numbers, dates and units | Wan (ten thousand) converted wrongly; dates in the wrong order | Check every figure against the source |
| Legal and contract terms | Indemnify or warranty translated with an everyday word | Use a glossary; have contracts reviewed by a qualified person |
| Tone and politeness | A blunt reply to a long-standing supplier | State the audience and tone in the prompt |
| Simplified vs Traditional | Traditional characters sent to a Singapore or mainland reader | Say Simplified Chinese explicitly |
| Singapore terms | HDB, CPF, GST or IRAS translated literally | Tell the model to keep local acronyms |
WMT25 also found that output quality varied by type of text, with speech transcripts hardest and literary text easiest for systems overall. Business email and chat sit in between.
Choosing a tool: data terms and workflow matter more than scores
Because quality is close at the top, decide on how your data is handled and how the tool fits your work.
Business AI plan (ChatGPT, Claude, Gemini)
- Good for drafts, replies, rewriting tone and explaining terms
- Business plans do not train on your data by default
- Can follow instructions on names, glossary and tone
- Formatting of long documents may need fixing
Best for: Emails, chats, marketing text and internal documents.
Dedicated translator (DeepL, Google)
- Translates whole files and keeps layout
- Glossaries and consistent terminology
- Paid plans with clear no-training terms
- Less flexible on tone and rewriting
Best for: Manuals, product sheets, website pages and large volumes.
Professional translator
- Accountable for accuracy
- Handles legal and certified translation
- Slower and more expensive
- Can review AI drafts instead of starting from scratch
Best for: Contracts, regulatory filings and anything you sign.
Our DeepL vs Google Translate vs ChatGPT comparison covers prices and file handling. For general model differences, see ChatGPT vs Claude vs Gemini for business, and for a Singapore-built model, our SEA-LION guide.
How to run your own 30-minute translation test
The best evidence for your business is your own documents.
Pick five real samples
A customer email, a product description, a quotation, a WhatsApp chat and one paragraph of terms. Remove personal data first.
Use the same prompt in each tool
For example: translate into Simplified Chinese for a Singapore business customer, polite but direct, keep names, numbers and acronyms unchanged.
Ask a fluent colleague to rate blind
Remove the tool names and ask them to score accuracy, tone and naturalness from 1 to 5, and to mark any error that would embarrass you.
Check numbers and names yourself
Compare every figure, date, unit and name with the source.
Translate back as a spot check
Translate one output back to English with a different tool. Big meaning shifts show up quickly.
Decide on fit, not just score
If two tools tie, pick the one with better data terms, file handling or integration with what you already use.
A human-review rule for Chinese-English translation
Set a simple rule so staff know when AI output can go straight out.
Translation review rule
Our ChatGPT at work policy guide explains how to write the data part of this rule under the PDPA.
Do it yourself or get help?
Most teams can start today with a business AI plan, a short prompt template and the review rule above. It gets more involved when you want translation built into your workflow, such as auto-translating incoming enquiries or website chat.
Our AI Website Assistant (S$790, paid upfront) can answer visitors in English and Chinese from your own content. Workflow Automation (S$390 per workflow) can route emails or form entries through translation and into your inbox or CRM.
Frequently asked questions
There is no clear winner in published evidence. The most recent human-graded benchmark, WMT25, tested English to Chinese and found Claude 4, DeepSeek V3, GPT-4.1 and Gemini 2.5 Pro within about three points of each other. No public human-graded test yet covers the September 2026 models, so test on your own documents.
On the WMT25 English to Chinese test set, several AI systems scored above the professional human reference translation. That does not make AI accountable for errors. For contracts, legal notices or anything signed, use a qualified translator, who can work from an AI draft to save time.
They suit different jobs. ChatGPT and similar models handle emails, tone changes and explanations well. DeepL and Google's document translation keep file layouts and support glossaries, which helps with manuals and product sheets. Quality at the top is close, so choose on data terms and workflow.
SEA-LION is built for Southeast Asian languages, and its SEA-HELM leaderboard covers Burmese, Filipino, Indonesian, Malay, Tamil, Thai and Vietnamese, not Chinese. For Chinese-English work, general models such as Claude, GPT, Gemini or Qwen, or dedicated tools such as DeepL, are the usual choices.
Use business plans with clear data terms. ChatGPT Business, DeepL paid plans and Google Cloud Translation all state that your content is not used for training. Avoid free personal accounts for confidential or personal data, and follow your company's AI use policy and the PDPA.