GPT-5.5 vs Grok-3
GPT-5.5 (2026) and Grok-3 (2025) are frontier-tier reasoning models from OpenAI and xAI. GPT-5.5 ships a 1.05m-token context window, while Grok-3 ships a 131k-token context window. On MMLU PRO, GPT-5.5 leads by 8.2 pts. On pricing, GPT-5.5 ranges from $5 to $8/1M input tokens by tier; Grok-3 costs $0.80/1M input tokens. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
GPT-5.5 fits 8x more tokens; pick it for long-context work and Grok-3 for tighter calls.
Decision scorecard
Local evidence first| Signal | GPT-5.5 | Grok-3 |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | reasoning-heavy apps, multimodal apps, and tool-calling agents |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 1.05m | 131k |
| Cheapest output | $30/1M tokens | $2.40/1M tokens |
| Provider routes | 3 tracked | 4 tracked |
| Shared benchmarks | MMLU PRO leader | 6 rows |
Decision tradeoffs
- GPT-5.5 holds a shared-benchmark lead on MMLU PRO, ahead by 8.2 points.
- GPT-5.5 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-5.5 uniquely exposes Code execution in local model data.
- Local decision data tags GPT-5.5 for Coding, RAG, and Agents.
- Grok-3 holds a shared-benchmark lead on AIME 2025, ahead by 12.1 points.
- Grok-3 has the lower cheapest tracked output price at $2.40/1M tokens.
- Grok-3 has broader tracked provider coverage for fallback and procurement flexibility.
- 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.
GPT-5.5
$11,500
Cheapest tracked route/tier: OpenAI API 0-272K input tokens
Grok-3
$1,240
Cheapest tracked route/tier: Chutes AI
Estimated monthly gap: $10,260. 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 $27.60/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Code execution before moving production traffic.
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- GPT-5.5 is $27.60/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- GPT-5.5 adds Code execution in local capability data.
Specs
Pricing and availability
| Pricing attribute | GPT-5.5 | Grok-3 |
|---|---|---|
| Input price |
| $0.80/1M tokens |
| Output price |
| $2.40/1M tokens |
| Providers |
Capabilities
| Capability | GPT-5.5 | Grok-3 |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | 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 | GPT-5.5 | Grok-3 |
|---|---|---|
| MMLU PRO | 88.1 | 79.9 |
| Google-Proof Q&A | 93.6 | 84.6 |
| AIME 2025 | 81.2 | 93.3 |
| HumanEval | 94.2 | 94.5 |
| Chatbot Arena | 1488.0 | 1405.0 |
| Aider Polyglot | 88.0 | 53.3 |
Deep dive
On shared benchmark coverage, MMLU PRO has GPT-5.5 at 88.1 and Grok-3 at 79.9, with GPT-5.5 ahead by 8.2 points; Google-Proof Q&A has GPT-5.5 at 93.6 and Grok-3 at 84.6, with GPT-5.5 ahead by 9 points; AIME 2025 has GPT-5.5 at 81.2 and Grok-3 at 93.3, with Grok-3 ahead by 12.1 points. The largest visible gap is 12.1 points on AIME 2025, 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 code execution: GPT-5.5. Both models share vision, multimodal input, reasoning mode, and function calling, 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, GPT-5.5 lists tiered pricing: 0-272K input tokens is $5/1M input and $30/1M output; 272K+ input tokens is $8/1M input and $36/1M output, 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 $11.22 per million blended tokens. For tiered rows, this cheapest-track view can understate interactive or fast-lane spend, so compare the tier you will actually use. Availability is 3 providers versus 4, so concentration risk also matters.
Choose GPT-5.5 when coding workflow support and larger context windows are central to the workload. Choose Grok-3 when vision-heavy evaluation, lower input-token cost, and broader provider choice 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, GPT-5.5 or Grok-3?
GPT-5.5 supports 1.05m 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, GPT-5.5 or Grok-3?
GPT-5.5 lists tiered pricing: 0-272K input tokens is $5/1M input and $30/1M output; 272K+ input tokens is $8/1M input and $36/1M output. Grok-3 lists $0.80/1M input and $2.40/1M output tokens on the cheapest tracked provider. Compare the tier you will actually use; cheap async pricing can overstate savings for interactive workflows. Provider discounts or batch pricing can still change the final bill.
Is GPT-5.5 or Grok-3 open source?
GPT-5.5 is listed under Proprietary. 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, GPT-5.5 or Grok-3?
Both GPT-5.5 and Grok-3 expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, GPT-5.5 or Grok-3?
Both GPT-5.5 and Grok-3 expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Where can I run GPT-5.5 and Grok-3?
GPT-5.5 is available on OpenAI API, OpenRouter, and Vercel AI Gateway. 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: 2026-06-08. Data sourced from public model cards and provider documentation.