GPT-5.5 Pro vs GPT-6 Astra
At a Glance
| Compare |  GPT-5.5 ProOpenAI | GPT-6 AstraOpenAI |
|---|---|---|
| Intelligence, Cost, and Efficiency | ||
| IntelligenceHigher is better · MM Intelligence v4.4 | #3 of 5790.9 score · 1/3 sources · single-source provisional · missing LiveBench, LMArena Text · full-core range 30.3–97.0 | #6 of 5784.6 score · 3/3 sources · complete |
| CostLower is better · Published-token output estimate | UnrankedNot in the 27-model eligible cohort | #26 of 27$0.520 per LiveBench case |
| EfficiencyHigher is better · MM Efficiency v1.9 | UnrankedNot in the 27-model eligible cohort | #18 of 2746.1 score · 3/3 sources · complete |
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | $30.00Openai ↗ · Sep 3, 2026 | $10.00Openai ↗ · Sep 4, 2026 |
| Output priceFrom · USD / 1M tokens | $180.00Openai ↗ · Sep 3, 2026 | $50.00Openai ↗ · Sep 4, 2026 |
| Context windowMaximum documented tokens | 1,050K | 1,050K |
| Model facts checked | Sep 3, 2026View model evidence → | Sep 4, 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
| Benchmark | GPT-5.5 Pro | GPT-6 Astra |
|---|---|---|
| ARC-AGI-1verified-v1-613c385b0c93 · verified_score · leader | 96.5098% of row best · percent · GPT-5.5 Pro (High) | 98.50100% of row best · percent · GPT-6 Astra (XHigh) |
| ARC-AGI-2verified-v2-be40992860f9 · verified_score · leader | 84.5889% of row best · percent · GPT-5.5 Pro (High) | 95.00100% of row best · percent · GPT-6 Astra (Max) |
| Overall ResultCounted from the protocol-matched rows above | 0 benchmark winsNo overall winner | 2 benchmark winsNo overall winner |
Third-party benchmark Only like-for-like primary-publisher results are shown; raw scores, relative scores, configuration, and token spend remain visible.
Side-by-Side Facts
| Field | GPT-5.5 Pro | GPT-6 Astra |
|---|---|---|
| Developer | OpenAI | OpenAI |
| Family | Gpt 5 5 | Gpt 6 |
| Model | GPT-5.5 Pro | GPT-6 Astra |
| Version | GPT-5.5 Pro | GPT-6 Astra |
| Lifecycle | active | active |
| Released | 2026-04-23 | 2026-09-03 |
| Knowledge cutoff | 2025-12-01 | 2026-04-30 |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 1,050K | 1,050K |
| 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) | Openai (Standard), Openrouter (Standard) |
| Capabilities | chat, generation, reasoning, structured_outputs, tools | chat, computer-use, generation, reasoning, research, tools |
GPT-5.5 Pro Capabilities
GPT-6 Astra Capabilities
Related Comparisons
All image comparisons →| A | Pair | B | Context |
|---|---|---|---|
Claude Opus 4.6Anthropic | vs | GPT-5.5 ProOpenAI | cross-developer peersimage, text |
Claude Opus 4.7Anthropic | vs | GPT-5.5 ProOpenAI | cross-developer peersimage, text |
Claude Opus 5Anthropic | vs | GPT-5.5 ProOpenAI | cross-developer peersimage, text |
Claude Sonnet 4.6Anthropic | vs | GPT-5.5 ProOpenAI | cross-developer peersimage, text |
 Gemini 3.5 FlashGoogle DeepMind | vs | GPT-5.5 ProOpenAI | cross-developer peerstext |
Gemini 3.5 Flash-LiteGoogle DeepMind | vs | GPT-5.5 ProOpenAI | cross-developer peerstext |
Gemini 3.6 FlashGoogle DeepMind | vs | GPT-5.5 ProOpenAI | cross-developer peerstext |
Gemini 3.7 FlashGoogle DeepMind | vs | GPT-5.5 ProOpenAI | cross-developer peerstext |
GPT-4.1OpenAI | vs | GPT-5.5 ProOpenAI | family variantsimage, text |
GPT-4.1 MiniOpenAI | vs | GPT-5.5 ProOpenAI | family variantsimage, text |
Primary Evidence
Sources and Freshness
Questions
GPT-5.5 Pro vs GPT-6 Astra FAQs
Is GPT-5.5 Pro or GPT-6 Astra better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both GPT-5.5 Pro and GPT-6 Astra, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, GPT-5.5 Pro or GPT-6 Astra?+
GPT-5.5 Pro is $30.00 and GPT-6 Astra is $10.00 per million tokens, so GPT-6 Astra is cheaper on this metric. GPT-5.5 Pro is $180.00 and GPT-6 Astra is $50.00 per million tokens, so GPT-6 Astra is cheaper on this metric.
Which has a larger context window, GPT-5.5 Pro or GPT-6 Astra?+
Both models have the same sourced context window: 1,050,000 tokens each.
Which performs better in benchmarks, GPT-5.5 Pro or GPT-6 Astra?+
There is no overall benchmark winner: An overall winner requires at least two decisive benchmarks from at least two original publishers.
Can GPT-5.5 Pro or GPT-6 Astra be self-hosted?+
Both models have the same sourced self-hosting status: unsupported. GPT-5.5 Pro is not marked open weight; GPT-6 Astra is not marked open weight.
Can GPT-5.5 Pro and GPT-6 Astra understand images?+
GPT-5.5 Pro is documented with image input; GPT-6 Astra is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, GPT-5.5 Pro or GPT-6 Astra?+
Both models have the same sourced maximum output: 128,000 tokens each.
Do GPT-5.5 Pro and GPT-6 Astra support reasoning and tool use?+
GPT-5.5 Pro: reasoning, tool calling, and image input. GPT-6 Astra: 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 GPT-6 Astra?+
GPT-5.5 Pro has 2 sourced provider routes; GPT-6 Astra has 2, a tie.
Which offers better value, GPT-5.5 Pro or GPT-6 Astra?+
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.