GPT-4o (05-13) vs Grok 4
GPT-4o (05-13) (2024) and Grok 4 (2025) are frontier reasoning models from OpenAI and xAI. GPT-4o (05-13) ships a 128k-token context window, while Grok 4 ships a 256k-token context window. On MMLU PRO, Grok 4 leads by 14.5 pts. On pricing, Grok 4 costs $1.25/1M input tokens versus $2.50/1M 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.
Grok 4 is ~100% cheaper at $1.25/1M; pay for GPT-4o (05-13) only for coding workflow support.
Decision scorecard
Local evidence first| Signal | GPT-4o (05-13) | Grok 4 |
|---|---|---|
| Best for | multimodal apps 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 | 128k | 256k |
| Cheapest output | $10/1M tokens | $2.50/1M tokens |
| Provider routes | 4 tracked | 4 tracked |
| Shared benchmarks | 1 shared | MMLU PRO leader |
Decision tradeoffs
- Local decision data tags GPT-4o (05-13) for Coding, RAG, and Agents.
- Grok 4 holds a shared-benchmark lead on MMLU PRO, ahead by 14.5 points.
- Grok 4 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Grok 4 has the lower cheapest tracked output price at $2.50/1M tokens.
- Grok 4 uniquely exposes Reasoning, Function calling, and Tool use in local model data.
- Local decision data tags Grok 4 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-4o (05-13)
$4,500
Cheapest tracked route/tier: OpenAI API
Grok 4
$1,625
Cheapest tracked route/tier: xAI Console
Estimated monthly gap: $2,875. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter and Replicate API; start route-level A/B tests there.
- Grok 4 is $7.50/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Grok 4 adds Reasoning, Function calling, and Tool use in local capability data.
- Provider overlap exists on OpenRouter and Replicate API; start route-level A/B tests there.
- GPT-4o (05-13) is $7.50/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Reasoning, Function calling, and Tool use before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2024-05-13 | 2025-07-09 |
| Context window | 128k | 256k |
| Parameters | 1.76T (8x222B MoE)* | — |
| Architecture | Mixture of Experts | Decoder Only |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | 2023-10 | - |
Pricing and availability
| Pricing attribute | GPT-4o (05-13) | Grok 4 |
|---|---|---|
| Input price | $2.50/1M tokens | $1.25/1M tokens |
| Output price | $10/1M tokens | $2.50/1M tokens |
| Providers |
Capabilities
| Capability | GPT-4o (05-13) | Grok 4 |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | No | Yes |
| Function calling | No | Yes |
| Tool use | No | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | GPT-4o (05-13) | Grok 4 |
|---|---|---|
| MMLU PRO | 72.5 | 87.0 |
Deep dive
On shared benchmark coverage, MMLU PRO has GPT-4o (05-13) at 72.5 and Grok 4 at 87, with Grok 4 ahead by 14.5 points. The largest visible gap is 14.5 points on MMLU PRO, 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 reasoning mode: Grok 4, function calling: Grok 4, and tool use: Grok 4. Both models share vision, multimodal input, structured outputs, and code execution, 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-4o (05-13) lists $2.50/1M input and $10/1M output tokens on the cheapest tracked provider, while Grok 4 lists $1.25/1M input and $2.50/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Grok 4 lower by about $3.13 per million blended tokens. Availability is 4 providers versus 4, so concentration risk also matters.
Choose GPT-4o (05-13) when coding workflow support are central to the workload. Choose Grok 4 when coding workflow support, larger context windows, 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, GPT-4o (05-13) or Grok 4?
Grok 4 supports 256k tokens, while GPT-4o (05-13) supports 128k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, GPT-4o (05-13) or Grok 4?
Grok 4 is cheaper on tracked token pricing. GPT-4o (05-13) costs $2.50/1M input and $10/1M output tokens. Grok 4 costs $1.25/1M input and $2.50/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is GPT-4o (05-13) or Grok 4 open source?
GPT-4o (05-13) is listed under Proprietary. Grok 4 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-4o (05-13) or Grok 4?
Both GPT-4o (05-13) and Grok 4 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-4o (05-13) or Grok 4?
Both GPT-4o (05-13) and Grok 4 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-4o (05-13) and Grok 4?
GPT-4o (05-13) is available on Azure OpenAI, OpenAI API, OpenRouter, and Replicate API. Grok 4 is available on Microsoft Foundry, OpenRouter, Replicate API, and xAI Console. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-06-15. Data sourced from public model cards and provider documentation.