Grok 4 vs o3
Grok 4 (2026) and o3 (2025) are frontier-tier reasoning models from xAI and OpenAI. Grok 4 ships a 256k-token context window, while o3 ships a 200K-token context window. On SWE-bench Verified, Grok 4 leads by 5 pts. On pricing, o3 costs $2/1M input tokens versus $3/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
o3 is ~50% cheaper at $2/1M; pay for Grok 4 only for coding workflow support.
Specs
Pricing and availability
| Pricing attribute | Grok 4 | o3 |
|---|---|---|
| Input price | $3/1M tokens | $2/1M tokens |
| Output price | $15/1M tokens | $8/1M tokens |
| Providers |
Capabilities
| Capability | Grok 4 | o3 |
|---|---|---|
| Vision | No | No |
| Multimodal | Yes | No |
| Reasoning | Yes | Yes |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | Yes | Yes |
| Code execution | Yes | Yes |
Benchmarks
| Benchmark | Grok 4 | o3 |
|---|---|---|
| SWE-bench Verified | 76.7 | 71.7 |
| Aider Polyglot | 79.6 | 81.3 |
Deep dive
On shared benchmark coverage, SWE-bench Verified has Grok 4 at 76.7 and o3 at 71.7, with Grok 4 ahead by 5 points; Aider Polyglot has Grok 4 at 79.6 and o3 at 81.3, with o3 ahead by 1.7 points. The largest visible gap is 5 points on SWE-bench Verified, 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 multimodal input: Grok 4, function calling: Grok 4, and tool use: Grok 4. Both models share reasoning mode, 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, Grok 4 lists $3/1M input and $15/1M output tokens, while o3 lists $2/1M input and $8/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts o3 lower by about $2.8 per million blended tokens. Availability is 3 providers versus 2, so concentration risk also matters.
Choose Grok 4 when coding workflow support, larger context windows, and broader provider choice are central to the workload. Choose o3 when coding workflow support 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, Grok 4 or o3?
Grok 4 supports 256k tokens, while o3 supports 200K 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, Grok 4 or o3?
o3 is cheaper on tracked token pricing. Grok 4 costs $3/1M input and $15/1M output tokens. o3 costs $2/1M input and $8/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Grok 4 or o3 open source?
Grok 4 is listed under Proprietary. o3 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 multimodal input, Grok 4 or o3?
Grok 4 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.
Which is better for reasoning mode, Grok 4 or o3?
Both Grok 4 and o3 expose reasoning mode. 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 Grok 4 and o3?
Grok 4 is available on Microsoft Foundry, OpenRouter, and Replicate API. o3 is available on OpenAI API and OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-11. Data sourced from public model cards and provider documentation.