GPT-5 Pro vs Grok 4.3
GPT-5 Pro (2025) and Grok 4.3 (2026) are frontier reasoning models from OpenAI and xAI. GPT-5 Pro ships a 400k-token context window, while Grok 4.3 ships a 1m-token context window. On pricing, GPT-5 Pro costs $15/1M input tokens; Grok 4.3 ranges from $1.25 to $2.50/1M input tokens by tier. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Grok 4.3 is safer overall; choose GPT-5 Pro when coding workflow support matters.
Decision scorecard
Local evidence first| Signal | GPT-5 Pro | Grok 4.3 |
|---|---|---|
| Best for | multimodal apps and tool-calling agents | reasoning-heavy apps, multimodal apps, and tool-calling agents |
| Decision fit | Coding, RAG, and Agents | RAG, Agents, and Long context |
| Context window | 400k | 1m |
| Cheapest output | $120/1M tokens | $2.50/1M tokens |
| Provider routes | 1 tracked | 4 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- GPT-5 Pro uniquely exposes Code execution in local model data.
- Local decision data tags GPT-5 Pro for Coding, RAG, and Agents.
- Grok 4.3 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Grok 4.3 has the lower cheapest tracked output price at $2.50/1M tokens.
- Grok 4.3 has broader tracked provider coverage for fallback and procurement flexibility.
- Grok 4.3 uniquely exposes Reasoning in local model data.
- Local decision data tags Grok 4.3 for RAG, Agents, and Long context.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
GPT-5 Pro
$42,000
Cheapest tracked route/tier: Vercel AI Gateway
Grok 4.3
$1,625
Cheapest tracked route/tier: xAI Console
Estimated monthly gap: $40,375. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Vercel AI Gateway; start route-level A/B tests there.
- Grok 4.3 is $118/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Code execution before moving production traffic.
- Grok 4.3 adds Reasoning in local capability data.
- Provider overlap exists on Vercel AI Gateway; start route-level A/B tests there.
- GPT-5 Pro is $118/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Reasoning before moving production traffic.
- GPT-5 Pro adds Code execution in local capability data.
Specs
Pricing and availability
| Pricing attribute | GPT-5 Pro | Grok 4.3 |
|---|---|---|
| Input price | $15/1M tokens |
|
| Output price | $120/1M tokens |
|
| Providers |
Capabilities
| Capability | GPT-5 Pro | Grok 4.3 |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | No | 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
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on reasoning mode: Grok 4.3 and code execution: GPT-5 Pro. Both models share vision, multimodal input, function calling, and tool use, 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 Pro lists $15/1M input and $120/1M output tokens on the cheapest tracked provider, while Grok 4.3 lists tiered pricing: 0-200,001t is $1.25/1M input and $2.50/1M output; 200,001t+ is $2.50/1M input and $5/1M output. A 70/30 input-output blend puts Grok 4.3 lower by about $44.88 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 1 providers versus 4, so concentration risk also matters.
Choose GPT-5 Pro when coding workflow support are central to the workload. Choose Grok 4.3 when reasoning depth, larger context windows, and lower cheapest-tier 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-5 Pro or Grok 4.3?
Grok 4.3 supports 1m tokens, while GPT-5 Pro supports 400k 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-5 Pro or Grok 4.3?
GPT-5 Pro lists $15/1M input and $120/1M output tokens on the cheapest tracked provider. Grok 4.3 lists tiered pricing: 0-200,001t is $1.25/1M input and $2.50/1M output; 200,001t+ is $2.50/1M input and $5/1M output. 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 Pro or Grok 4.3 open source?
GPT-5 Pro is listed under Proprietary. Grok 4.3 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 Pro or Grok 4.3?
Both GPT-5 Pro and Grok 4.3 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 Pro or Grok 4.3?
Both GPT-5 Pro and Grok 4.3 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 Pro and Grok 4.3?
GPT-5 Pro is available on Vercel AI Gateway. Grok 4.3 is available on xAI Console, OpenRouter, Microsoft Foundry, and Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-05-25. Data sourced from public model cards and provider documentation.