Grok-3 vs o3
Grok-3 (2025) and o3 (2025) are frontier-tier reasoning models from xAI and OpenAI. Grok-3 ships a 131k-token context window, while o3 ships a 200k-token context window. On Google-Proof Q&A, o3 leads by 3.1 pts. On pricing, Grok-3 costs $0.80/1M input tokens versus $2/1M 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-3 is ~150% cheaper at $0.80/1M; pay for o3 only for coding workflow support.
Decision scorecard
Local evidence first| Signal | Grok-3 | 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 | 131k | 200k |
| Cheapest output | $2.40/1M tokens | $8/1M tokens |
| Provider routes | 4 tracked | 3 tracked |
| Shared benchmarks | 6 rows | Google-Proof Q&A leader |
Decision tradeoffs
- Grok-3 leads the largest shared benchmark signal on LiveCodeBench by 0.3 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.
- o3 leads the largest shared benchmark signal on Google-Proof Q&A by 3.1 points.
- o3 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- o3 uniquely exposes Code execution in local model data.
- 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-3
$1,240
Cheapest tracked route/tier: Chutes AI
o3
$3,600
Cheapest tracked route/tier: OpenAI API
Estimated monthly gap: $2,360. 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 $5.60/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- o3 adds Code execution in local capability data.
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- Grok-3 is $5.60/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Code execution before moving production traffic.
Specs
Pricing and availability
| Pricing attribute | Grok-3 | o3 |
|---|---|---|
| Input price | $0.80/1M tokens | $2/1M tokens |
| Output price | $2.40/1M tokens | $8/1M tokens |
| Providers |
Capabilities
| Capability | Grok-3 | o3 |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | No | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Grok-3 | o3 |
|---|---|---|
| Google-Proof Q&A | 84.6 | 87.7 |
| HumanEval | 94.5 | 96.7 |
| Aider Polyglot | 53.3 | 81.3 |
| Chatbot Arena | 1405.0 | 1412.0 |
| Massive Multi-discipline Multimodal Understanding | 78.0 | 82.9 |
| LiveCodeBench | 79.4 | 79.1 |
Deep dive
On shared benchmark coverage, Google-Proof Q&A has Grok-3 at 84.6 and o3 at 87.7, with o3 ahead by 3.1 points; HumanEval has Grok-3 at 94.5 and o3 at 96.7, with o3 ahead by 2.2 points; Aider Polyglot has Grok-3 at 53.3 and o3 at 81.3, with o3 ahead by 28 points. The largest visible gap is 28 points on Aider Polyglot, 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: o3. 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, Grok-3 lists $0.80/1M input and $2.40/1M output tokens on the cheapest tracked provider, while o3 lists $2/1M input and $8/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Grok-3 lower by about $2.52 per million blended tokens. Availability is 4 providers versus 3, so concentration risk also matters.
Choose Grok-3 when vision-heavy evaluation, lower input-token cost, and broader provider choice are central to the workload. Choose o3 when coding workflow support and larger context windows 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-3 or o3?
o3 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, Grok-3 or o3?
Grok-3 is cheaper on tracked token pricing. Grok-3 costs $0.80/1M input and $2.40/1M 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-3 or o3 open source?
Grok-3 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-3 or o3?
Both Grok-3 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-3 or o3?
Both Grok-3 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-3 and o3?
Grok-3 is available on OpenRouter, xAI Console, Chutes AI, and Microsoft Foundry. o3 is available on OpenAI API, OpenRouter, and Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-29. Data sourced from public model cards and provider documentation.