A bar fills towards the model's side; yellow is a clear difference, grey falls within the margin of measurement.
| Criterion | ChatGPT | GLM (Z.ai) |
|---|---|---|
| Quality (Elo)Quality from blind duels on LMArena: users choose between two anonymous answers. A difference of about 20 points is noticeable, a few points is noise. How we measure | 1485 | 1483 |
| Editorial scoreOur own assessment on 10 of suitability for professional work, price and privacy. This is a judgement, not a measurement; that is why it always sits alongside the Elo. How we measure | 8,9 / 10 | 7,7 / 10 |
| Code EloThe same blind duels on LMArena, but only with programming tasks. How we measure | 1767 | 1622 |
| API price in, per 1M | $10 | $0.07 |
| API price out, per 1M | $50 | $1.4 |
| Entry price (subscription) | $8 / month | $18 / month |
| Business | from $20 / seat (Business / API) | on request |
| Context window | ~1M tokens | 1M tokens |
| Modalities | Text, Image, Speech, Code | Text, Image |
| EU hosting | Yes | No |
| Self-hostable | No | Yes |
| No training (business) | Yes | No |
| GDPR profileOur summary of what the provider itself publishes about your data. For a professional tool: whether the data is stored in the EU, whether there is a certification or GDPR guarantee, and whether the provider is based in the Netherlands or the EU. For a general model: EU hosting, no training on your data and self-hosting. From Strong to Unknown; Caution only for a model with a documented problem. How we measure | Strong | Caution |
Source: LMArena, OpenRouter · retrieved 9 November 2026
Choose ChatGPT if…
- you consider versatility across a wide range of tasks important
- you consider strength in agentic coding and debugging important
- you want the highest overall quality
- privacy and GDPR weigh heavily
- price is a decisive factor
Choose GLM (Z.ai) if…
- top performance on coding and agent benchmarks at a fraction of the price matters to you
- a fully open-weight GLM-5.2 under the MIT licence matters to you
Frequently asked questions
By field
Which is better: ChatGPT or GLM (Z.ai)?
On combined quality (LMArena Elo + our editorial score), ChatGPT comes out higher, but the right choice depends on your field and requirements: GLM (Z.ai) may suit you better on price or privacy. See the table above.
Which is better for privacy and GDPR: ChatGPT or GLM (Z.ai)?
ChatGPT scores stronger here (EU hosting, on-premise and no training on your data). ChatGPT: EU data residency available for Enterprise, Edu and the API. Business and API data are not used for training by default; consumer tiers (Free/Plus/Pro) are, unless you turn this off.
Which is cheaper: ChatGPT or GLM (Z.ai)?
ChatGPT has the lowest entry price. Always check current prices, as they change often.
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