GPT-5.3 Codex vs GPT-5.5 Pro
At a Glance
| Compare |  GPT-5.3 CodexOpenAI | GPT-5.5 ProOpenAI |
|---|---|---|
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | $1.75Openai ↗ · Sep 3, 2026 | $30.00Openai ↗ · Sep 3, 2026 |
| Output priceFrom · USD / 1M tokens | $14.00Openai ↗ · Sep 3, 2026 | $180.00Openai ↗ · Sep 3, 2026 |
| Context windowMaximum documented tokens | 400K | 1,050K |
| 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-5.3-Codex | GPT-5.5 Pro |
|---|---|---|
| Developer | OpenAI | OpenAI |
| Family | Gpt 5 3 | Gpt 5 5 |
| Model | GPT-5.3-Codex | GPT-5.5 Pro |
| Version | GPT-5.3-Codex | GPT-5.5 Pro |
| Lifecycle | active | active |
| Released | Unknown | 2026-04-23 |
| Knowledge cutoff | 2025-08-31 | 2025-12-01 |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 400K | 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, generation, reasoning, structured_outputs, tools |
GPT-5.3 Codex Capabilities
GPT-5.5 Pro Capabilities
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Primary Evidence
Sources and Freshness
Questions
GPT-5.3 Codex vs GPT-5.5 Pro FAQs
Is GPT-5.3 Codex or GPT-5.5 Pro better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both GPT-5.3 Codex and GPT-5.5 Pro, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, GPT-5.3 Codex or GPT-5.5 Pro?+
GPT-5.3 Codex is $1.75 and GPT-5.5 Pro is $30.00 per million tokens, so GPT-5.3 Codex is cheaper on this metric. GPT-5.3 Codex is $14.00 and GPT-5.5 Pro is $180.00 per million tokens, so GPT-5.3 Codex is cheaper on this metric.
Which has a larger context window, GPT-5.3 Codex or GPT-5.5 Pro?+
GPT-5.5 Pro has the larger sourced context window. GPT-5.3 Codex supports 400K and GPT-5.5 Pro supports 1,050K.
Which performs better in benchmarks, GPT-5.3 Codex or GPT-5.5 Pro?+
There is no overall benchmark winner: At least two independently verified, protocol-matched benchmarks are required for an overall winner.
Can GPT-5.3 Codex or GPT-5.5 Pro be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. GPT-5.3 Codex is not marked open weight; GPT-5.5 Pro is not marked open weight.
Can GPT-5.3 Codex and GPT-5.5 Pro understand images?+
GPT-5.3 Codex is documented with image input; GPT-5.5 Pro is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, GPT-5.3 Codex or GPT-5.5 Pro?+
Neither has a larger sourced maximum output. GPT-5.3 Codex is 128K and GPT-5.5 Pro is 128K.
Do GPT-5.3 Codex and GPT-5.5 Pro support reasoning and tool use?+
GPT-5.3 Codex: reasoning, tool calling, and image input. GPT-5.5 Pro: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, GPT-5.3 Codex or GPT-5.5 Pro?+
GPT-5.3 Codex has 2 sourced provider routes; GPT-5.5 Pro has 2, a tie.
Which offers better value, GPT-5.3 Codex or GPT-5.5 Pro?+
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.