Z.ai: GLM 5.1
The Z.ai: GLM 5.1 is an AI model that handles text inputs and supports tool integration. It has a maximum context length of 204800 tokens and can process up to 128000 completion tokens per input. The model also supports reasoning capabilities. When considering this model for your project, evaluate its price point against its performance. With a blended benchmark score of 65.8 across two independent benchmarks, the Z.ai: GLM 5.1 falls in the middle ground. Its pricing structure is $0.966 per million input tokens and $3.036 per million output tokens. If budget constraints are not a major concern and you require tool integration and reasoning capabilities, the Z.ai: GLM 5.1 may be worth shortlisting for further evaluation.
Benchmark results
Independent, published benchmarks. Blended score 63.5 across 2 benchmarks, last refreshed 2026-10-13. How scoring works →
| Benchmark | Measures | Score |
|---|---|---|
| AI Index | broad capability composite | 43.0 |
| EQ-Bench | emotional understanding in dialogue | 75.2 |
- Model ID
- z-ai/glm-5.1
- Vendor
- z-ai
- Released
- April 2026
- Tokenizer
- Other
- Input Modalities
- text
- Output Modalities
- text
- Max Output
- 128,000 tokens
- Tool Calling
- ✓ supported
- Structured Output
- ✓ supported
- Reasoning Mode
- ✓ supported
- Vision
- text only
- Audio
- no
- Moderated
- no
What it costs in practice
Computed from the current $0.97/M input and $3.04/M output rates. Run your own numbers →
| Job | Tokens | Cost |
|---|---|---|
| Summarize a 50-page report | 30k in / 1.5k out | $0.03 |
| Classify 1,000 customer emails | 500k in / 50k out | $0.63 |
| A month of a busy support chatbot | 5M in / 2M out | $10.90 |
Price & spec history
Tracked daily by PicksByModel since 2026-07-17.
| Date | Input /M | Output /M | Context |
|---|---|---|---|
| 2026-10-07 | $0.97 | $3.04 | 204,800 |
| 2026-10-03 | $1.40 | $4.40 | 204,800 |
| 2026-10-01 | $0.96 | $3.03 | 204,800 |
| 2026-09-28 | $1.40 | $4.40 | 204,800 |
| 2026-09-25 | $0.96 | $3.03 | 204,800 |
| 2026-09-01 | $0.97 | $3.04 | 204,800 |
| 2026-08-25 | $1.26 | $3.96 | 204,800 |
| 2026-08-15 | $0.97 | $3.04 | 204,800 |
| 2026-08-10 | $1.40 | $4.40 | 204,800 |
| 2026-08-06 | $0.95 | $2.99 | 204,800 |
| 2026-07-22 | $0.97 | $3.04 | 204,800 |
| 2026-07-17 | $0.97 | $3.04 | 202,752 |
Similar models
Z.ai: GLM 5.3
Z.ai: GLM 4.7
Z.ai: GLM 5 Turbo
Z.ai: GLM 5
Z.ai: GLM 5.3 (batch)
Z.ai: GLM 4.6
Quick answers
- How much does Z.ai: GLM 5.1 cost?
- $0.97 per million input tokens and $3.04 per million output tokens.
- What is Z.ai: GLM 5.1's context window?
- 204,800 tokens, roughly 307 pages of text in a single request.
- Does Z.ai: GLM 5.1 support tool calling?
- It supports tool calling, structured output, a reasoning mode.
- Can Z.ai: GLM 5.1 process images?
- No, it is text-only on the input side.