Grok 4 vs o3
Grok 4 (2025) 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, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
o3 is ~50% cheaper at $2/1M; pay for Grok 4 only for coding workflow support.
Decision scorecard
Local evidence first| Signal | Grok 4 | o3 |
|---|---|---|
| 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 | 256K | 200K |
| Cheapest output | $15/1M tokens | $8/1M tokens |
| Provider routes | 4 tracked | 3 tracked |
| Shared benchmarks | SWE-bench Verified leader | 9 shared |
Decision tradeoffs
- Grok 4 holds a shared-benchmark lead on SWE-bench Verified, ahead by 5 points.
- Grok 4 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Grok 4 has broader tracked provider coverage for fallback and route flexibility.
- Local decision data tags Grok 4 for Coding, RAG, and Agents.
- o3 holds a shared-benchmark lead on Google-Proof Q&A, ahead by 0.2 points.
- o3 has the lower cheapest tracked output price at $8/1M tokens.
- Local decision data tags o3 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.
Grok 4
$6,150
Cheapest tracked route/tier: Microsoft Foundry
o3
$3,600
Cheapest tracked route/tier: OpenAI API
Estimated monthly gap: $2,550. 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.
- o3 is $7/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- Grok 4 is $7/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
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 | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| JSON / Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Grok 4 | o3 |
|---|---|---|
| SWE-bench Verified | 76.7 | 71.7 |
| Google-Proof Q&A | 87.5 | 87.7 |
| AIME 2025 | 91.7 | 88.9 |
| LiveCodeBench | 79.0 | 85.5 |
| Humanity's Last Exam | 25.4 | 20.3 |
| LMArena Text Arena - Creative Writing | 1397.0 | 1358.0 |
| LMArena Vision Arena | 1184.0 | 1216.0 |
| Aider Polyglot | 79.6 | 81.3 |
| BFCL | 63.0 | 63.0 |
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; Google-Proof Q&A has Grok 4 at 87.5 and o3 at 87.7, with o3 ahead by 0.2 points; AIME 2025 has Grok 4 at 91.7 and o3 at 88.9, with Grok 4 ahead by 2.8 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 is close: both models cover vision, multimodal input, reasoning mode, JSON / Tool use, and JSON / Tool use. That makes context budget, benchmark fit, and provider maturity more important than a simple checklist. If your application depends on one integration detail, verify it against the provider route you plan to use, not just the base model listing.
For cost, Grok 4 lists $3/1M input and $15/1M output tokens on the cheapest listed provider, while o3 lists $2/1M input and $8/1M output tokens on the cheapest listed provider. A 70/30 input-output blend puts o3 lower by about $2.80 per million blended tokens. Availability is 4 providers versus 3, 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 listed 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 vision, Grok 4 or o3?
Both Grok 4 and o3 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, Grok 4 or o3?
Both Grok 4 and o3 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 Grok 4 and o3?
Grok 4 is available on Microsoft Foundry, OpenRouter, Replicate API, and xAI Console. o3 is available on OpenAI API, OpenRouter, and Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-10-27. Data sourced from public model cards and provider documentation.