GLM-5.2 vs Grok-4.20 Reasoning — Price, Context, and Capability Compared
GLM-5.2 vs Grok-4.20 Reasoning: which should I use?
Grok-4.20 Reasoning costs 1.4× more per blended million tokens than GLM-5.2. GLM-5.2 has the larger context window (1,000,000 tokens). Default to GLM-5.2 unless you specifically need Grok-4.20 Reasoning's edge.
Price, speed, and task evidence
Task verdict
Best-fit task signals from the published model strengths; this is not a substitute for a controlled benchmark.
| Fact | GLM-5.2 | Grok-4.20 Reasoning |
|---|---|---|
| Best fit | Long-horizon coding on open weights at a fraction of frontier pricing. | Long-document analysis and problems that benefit from explicit reasoning. |
| Reasoning mode | Available | Available |
Effective workload cost
Modeled for Coding Agent: 20,000 input + 2,000 output tokens per task, 1 turn. This is a workload model, not a provider quote.
| Fact | GLM-5.2 | Grok-4.20 Reasoning |
|---|---|---|
| Coding Agent / task | $0.04 (modeled) (winner) | $0.05 (modeled) |
| Input / output rate | $1.40 / $4.40 per M | $2.00 / $6.00 per M |
Speed
Only non-estimated benchmark results are shown as measured.
| Fact | GLM-5.2 | Grok-4.20 Reasoning |
|---|---|---|
| Measured throughput | Unavailable | 52 tokens/s |
| Time to first token | Unavailable | 540 ms |
API compatibility
Provider-level wire-format and SDK facts; model-specific parameter differences may still apply.
| Fact | GLM-5.2 | Grok-4.20 Reasoning |
|---|---|---|
| OpenAI SDK | Usable | Usable |
| Request shape | OpenAI-compatible chat/completions endpoint at api.z.ai/api/paas/v4. | Full OpenAI chat/completions compatibility — point the openai SDK at api.x.ai and it works unmodified. |
| Streaming | SSE (OpenAI delta) | SSE (OpenAI delta) |
Privacy and retention
Provider policy and residency facts from the verified provider registry. A missing retention policy is not treated as a guarantee.
| Fact | GLM-5.2 | Grok-4.20 Reasoning |
|---|---|---|
| Provider says API data trains models | Unavailable | Unavailable |
| Published retention period | Unavailable | Unavailable |
| Data residency | Unavailable | Unavailable |
Migration effort
Direction is from each displayed model to the other. Effort is derived from provider compatibility and published parameter maps.
| Fact | GLM-5.2 | Grok-4.20 Reasoning |
|---|---|---|
| Move GLM-5.2 → Grok-4.20 Reasoning | config; 1 breaking parameter difference | Target: Grok-4.20 Reasoning |
| Move Grok-4.20 Reasoning → GLM-5.2 | Source: Grok-4.20 Reasoning | config; 5 breaking parameter differences |
| Why | Keep the `openai` SDK; change `baseURL` and the API key. | Keep the `openai` SDK; change `baseURL` and the API key. |
Spec comparison
| GLM-5.2 | Grok-4.20 Reasoning | |
|---|---|---|
| Price (input) | $1.40/M ✓ | $2.00/M |
| Price (output) | $4.40/M ✓ | $6.00/M |
| Blended price | $2.15/M ✓ | $3.00/M |
| Context window | 1,000,000 tokens | 1,000,000 tokens |
| Max output | 64,000 tokens | 64,000 tokens |
| Modalities | text | text, vision |
| Reasoning mode | Yes | Yes |
| Released | 2026-05 | 2026-03 |
| Speed | Not measured | 52 t/s |
Cost at scale (3:1 blended)
| Tokens / month | GLM-5.2 | Grok-4.20 Reasoning | Delta |
|---|---|---|---|
| 1,000,000 | $2.15 | $3.00 | $0.85 (1.4×) |
| 10,000,000 | $21.50 | $30.00 | $8.50 (1.4×) |
| 100,000,000 | $215.00 | $300.00 | $85.00 (1.4×) |
Choose GLM-5.2 if…
- ✓Open-weights coding-first flagship
- ✓1M-token context window
- ✓Beats larger frontier models on long-horizon coding
- ✓Long-horizon coding on open weights at a fraction of frontier pricing.
Choose Grok-4.20 Reasoning if…
- ✓State-of-the-art document analysis at 1M context
- ✓Dedicated reasoning mode
- ✓Strong vision understanding
- ✓Long-document analysis and problems that benefit from explicit reasoning.
Run this exact matchup right now
Send the same prompt to GLM-5.2 and Grok-4.20 Reasoning side by side and see the outputs yourself.
Try GLM-5.2 vs Grok-4.20 Reasoning FreeFAQ
Is GLM-5.2 cheaper than Grok-4.20 Reasoning?
GLM-5.2 is cheaper, at $2.15 per million blended tokens vs $3.00 for Grok-4.20 Reasoning.
Which has the bigger context window, GLM-5.2 or Grok-4.20 Reasoning?
Both models support 1,000,000 tokens of context.
Can GLM-5.2 replace Grok-4.20 Reasoning for coding?
Both are viable for coding. Open-weights coding-first flagship (GLM-5.2) vs State-of-the-art document analysis at 1M context (Grok-4.20 Reasoning) — pick based on which strength matters more for your workload.
Neither of these? See GLM-5.2 alternatives or Grok-4.20 Reasoning alternatives.
Related
Pricing verified 2026-04-06. Specs verified 2026-08-08.