GLM-5.1 vs Grok-3
GLM-5.1 (2026) and Grok-3 (2025) are frontier-tier reasoning models from Zhipu AI and xAI. GLM-5.1 ships a 200k-token context window, while Grok-3 ships a 131k-token context window. On Google-Proof Q&A, GLM-5.1 leads by 1.6 pts. On pricing, Grok-3 costs $0.80/1M input tokens versus $0.98/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
GLM-5.1 is safer overall; choose Grok-3 when vision-heavy evaluation matters.
Decision scorecard
Local evidence first| Signal | GLM-5.1 | Grok-3 |
|---|---|---|
| Best for | reasoning-heavy apps, tool-calling agents, and provider-routed production | reasoning-heavy apps, multimodal apps, and tool-calling agents |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 200k | 131k |
| Cheapest output | $3.08/1M tokens | $2.40/1M tokens |
| Provider routes | 5 tracked | 4 tracked |
| Shared benchmarks | Google-Proof Q&A leader | 3 rows |
Decision tradeoffs
- GLM-5.1 holds a shared-benchmark lead on Google-Proof Q&A, ahead by 1.6 points.
- GLM-5.1 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GLM-5.1 has broader tracked provider coverage for fallback and procurement flexibility.
- GLM-5.1 uniquely exposes Code execution in local model data.
- Local decision data tags GLM-5.1 for Coding, RAG, and Agents.
- Grok-3 has the lower cheapest tracked output price at $2.40/1M tokens.
- Grok-3 uniquely exposes Vision and Multimodal in local model data.
- Local decision data tags Grok-3 for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
GLM-5.1
$1,554
Cheapest tracked route/tier: Z.ai
Grok-3
$1,240
Cheapest tracked route/tier: Chutes AI
Estimated monthly gap: $314. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- Grok-3 is $0.68/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Code execution before moving production traffic.
- Grok-3 adds Vision and Multimodal in local capability data.
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- GLM-5.1 is $0.68/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Vision and Multimodal before moving production traffic.
- GLM-5.1 adds Code execution in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-04-07 | 2025-02-17 |
| Context window | 200k | 131k |
| Parameters | 754B total, 40B active | — |
| Architecture | mixture of experts | - |
| License | MIT(OSI) | Proprietary |
| Openness | Open source | Proprietary |
| Commercial use | Commercial use allowed | Commercial use with conditions |
| Knowledge cutoff | 2025-11 | 2025-04 |
Pricing and availability
| Pricing attribute | GLM-5.1 | Grok-3 |
|---|---|---|
| Input price | $0.98/1M tokens | $0.80/1M tokens |
| Output price | $3.08/1M tokens | $2.40/1M tokens |
| Providers |
Capabilities
| Capability | GLM-5.1 | Grok-3 |
|---|---|---|
| Vision | No | Yes |
| Multimodal | No | Yes |
| Reasoning | Yes | Yes |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | GLM-5.1 | Grok-3 |
|---|---|---|
| Google-Proof Q&A | 86.2 | 84.6 |
| AIME 2025 | 95.3 | 93.3 |
| Chatbot Arena | 1472.0 | 1405.0 |
Deep dive
On shared benchmark coverage, Google-Proof Q&A has GLM-5.1 at 86.2 and Grok-3 at 84.6, with GLM-5.1 ahead by 1.6 points; AIME 2025 has GLM-5.1 at 95.3 and Grok-3 at 93.3, with GLM-5.1 ahead by 2 points; Chatbot Arena has GLM-5.1 at 1472 and Grok-3 at 1405, with GLM-5.1 ahead by 67 points. The largest visible gap is 67 points on Chatbot Arena, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint differs most on vision: Grok-3, multimodal input: Grok-3, and code execution: GLM-5.1. Both models share reasoning mode, function calling, tool use, and structured outputs, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, GLM-5.1 lists $0.98/1M input and $3.08/1M output tokens on the cheapest tracked provider, while Grok-3 lists $0.80/1M input and $2.40/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Grok-3 lower by about $0.33 per million blended tokens. Availability is 5 providers versus 4, so concentration risk also matters.
Choose GLM-5.1 when coding workflow support, larger context windows, and broader provider choice are central to the workload. Choose Grok-3 when vision-heavy evaluation and lower input-token cost are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, GLM-5.1 or Grok-3?
GLM-5.1 supports 200k tokens, while Grok-3 supports 131k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is cheaper, GLM-5.1 or Grok-3?
Grok-3 is cheaper on tracked token pricing. GLM-5.1 costs $0.98/1M input and $3.08/1M output tokens. Grok-3 costs $0.80/1M input and $2.40/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is GLM-5.1 or Grok-3 open source?
GLM-5.1 is listed under MIT. Grok-3 is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, GLM-5.1 or Grok-3?
Grok-3 has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, GLM-5.1 or Grok-3?
Grok-3 has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run GLM-5.1 and Grok-3?
GLM-5.1 is available on Z.ai, OpenRouter, Fireworks AI, Vercel AI Gateway, and Novita AI. Grok-3 is available on OpenRouter, xAI Console, Chutes AI, and Microsoft Foundry. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-25. Data sourced from public model cards and provider documentation.