GPT-5.5 Pro vs Grok 4.3
At a Glance
| Compare |  GPT-5.5 ProOpenAI | Grok 4.3xAI |
|---|---|---|
| Intelligence, Cost, and Efficiency | ||
| IntelligenceHigher is better · MM Intelligence v2.5 | UnrankedNot in the 46-model eligible cohort | #40 of 4616.6 score · 2/3 sources · provisional · missing ARC-AGI-2 · full-core range 11.1–44.4 |
| CostLower is better · Published-token output estimate | UnrankedNot in the 44-model eligible cohort | #7 of 44$0.028 per LiveBench case |
| EfficiencyHigher is better · MM Efficiency v1.5 | UnrankedNot in the 38-model eligible cohort | #33 of 3846.0 score · 2/3 sources · provisional · missing ARC-AGI-2 · full-core range 43.3–59.9 |
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | $30.00Openai ↗ · Sep 3, 2026 | $1.25Xai ↗ · Sep 3, 2026 |
| Output priceFrom · USD / 1M tokens | $180.00Openai ↗ · Sep 3, 2026 | $2.50Xai ↗ · Sep 3, 2026 |
| Context windowMaximum documented tokens | 1,050K | 1,000K |
| Model facts checked | Sep 3, 2026View model evidence → | Sep 3, 2026View model evidence → |
Token prices are the lowest available sourced USD rates; input and output may use different providers. Cost ranking estimates output spend on LiveBench, not a full request bill. Ranking methodology →
Available Benchmarks
Side-by-Side Facts
| Field | GPT-5.5 Pro | Grok 4.3 |
|---|---|---|
| Developer | OpenAI | xAI |
| Family | Gpt 5 5 | Grok 4 |
| Model | GPT-5.5 Pro | Grok 4.3 |
| Version | GPT-5.5 Pro | Grok 4.3 |
| Lifecycle | active | active |
| Released | 2026-04-23 | 2026-06-17 |
| Knowledge cutoff | 2025-12-01 | Unknown |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 1,050K | 1,000K |
| Total parameters | Unknown | Unknown |
| Active parameters | Unknown | Unknown |
| License | Unknown | Unknown |
| Open weights | No | No |
| API available | Yes | Yes |
| Self-hostable | No | No |
| Provider access | Openai (Standard), Openrouter (Standard) | Xai (Standard) |
| Capabilities | chat, generation, reasoning, structured_outputs, tools | chat, generation, reasoning, structured_outputs, tools |
GPT-5.5 Pro Capabilities
Grok 4.3 Capabilities
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Primary Evidence
Sources and Freshness
Questions
GPT-5.5 Pro vs Grok 4.3 FAQs
Is GPT-5.5 Pro or Grok 4.3 better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both GPT-5.5 Pro and Grok 4.3, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, GPT-5.5 Pro or Grok 4.3?+
GPT-5.5 Pro is $30.00 and Grok 4.3 is $1.25 per million tokens, so Grok 4.3 is cheaper on this metric. GPT-5.5 Pro is $180.00 and Grok 4.3 is $2.50 per million tokens, so Grok 4.3 is cheaper on this metric.
Which has a larger context window, GPT-5.5 Pro or Grok 4.3?+
GPT-5.5 Pro has the larger sourced context window. GPT-5.5 Pro supports 1,050K and Grok 4.3 supports 1,000K.
Which performs better in benchmarks, GPT-5.5 Pro or Grok 4.3?+
There is no overall benchmark winner: At least two independently verified, protocol-matched benchmarks are required for an overall winner.
Can GPT-5.5 Pro or Grok 4.3 be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. GPT-5.5 Pro is not marked open weight; Grok 4.3 is not marked open weight.
Can GPT-5.5 Pro and Grok 4.3 understand images?+
GPT-5.5 Pro is documented with image input; Grok 4.3 is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, GPT-5.5 Pro or Grok 4.3?+
Neither has a larger sourced maximum output. GPT-5.5 Pro is 128K and Grok 4.3 is —.
Do GPT-5.5 Pro and Grok 4.3 support reasoning and tool use?+
GPT-5.5 Pro: reasoning, tool calling, and image input. Grok 4.3: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, GPT-5.5 Pro or Grok 4.3?+
GPT-5.5 Pro has 2 sourced provider routes; Grok 4.3 has 1, so GPT-5.5 Pro has broader tracked availability.
Which offers better value, GPT-5.5 Pro or Grok 4.3?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.