Claude Opus 4.8 vs GPT-5.3 Codex
At a Glance
| Compare | Claude Opus 4.8Anthropic |  GPT-5.3 CodexOpenAI |
|---|---|---|
| Intelligence, Cost, and Efficiency | ||
| IntelligenceHigher is better · MM Intelligence v2.5 | #18 of 4670.1 score · 3/3 sources · complete | UnrankedNot in the 46-model eligible cohort |
| CostLower is better · Published-token output estimate | #42 of 44$0.604 per LiveBench case | UnrankedNot in the 44-model eligible cohort |
| EfficiencyHigher is better · MM Efficiency v1.5 | #35 of 3840.5 score · 3/3 sources · complete | UnrankedNot in the 38-model eligible cohort |
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | $5.00Anthropic ↗ · Sep 3, 2026 | $1.75Openai ↗ · Sep 3, 2026 |
| Output priceFrom · USD / 1M tokens | $25.00Anthropic ↗ · Sep 3, 2026 | $14.00Openai ↗ · Sep 3, 2026 |
| Context windowMaximum documented tokens | 1,000K | 400K |
| Model facts checked | Aug 29, 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 | Claude Opus 4.8 | GPT-5.3-Codex |
|---|---|---|
| Developer | Anthropic | OpenAI |
| Family | Claude 4 8 | Gpt 5 3 |
| Model | Claude Opus 4.8 | GPT-5.3-Codex |
| Version | Claude Opus 4.8 | GPT-5.3-Codex |
| Lifecycle | active | active |
| Released | 2026-05-28 | Unknown |
| Knowledge cutoff | 2026-01-01 | 2025-08-31 |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 1,000K | 400K |
| 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 | Anthropic (Standard), Deepinfra (Standard) | Openai (Standard), Openrouter (Standard) |
| Capabilities | chat, generation, reasoning, tools | chat, generation, reasoning, structured_outputs, tools |
Claude Opus 4.8 Capabilities
GPT-5.3 Codex Capabilities
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Primary Evidence
Sources and Freshness
Questions
Claude Opus 4.8 vs GPT-5.3 Codex FAQs
Is Claude Opus 4.8 or GPT-5.3 Codex better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Claude Opus 4.8 and GPT-5.3 Codex, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Claude Opus 4.8 or GPT-5.3 Codex?+
Claude Opus 4.8 is $5.00 and GPT-5.3 Codex is $1.75 per million tokens, so GPT-5.3 Codex is cheaper on this metric. Claude Opus 4.8 is $25.00 and GPT-5.3 Codex is $14.00 per million tokens, so GPT-5.3 Codex is cheaper on this metric.
Which has a larger context window, Claude Opus 4.8 or GPT-5.3 Codex?+
Claude Opus 4.8 has the larger sourced context window. Claude Opus 4.8 supports 1,000K and GPT-5.3 Codex supports 400K.
Which performs better in benchmarks, Claude Opus 4.8 or GPT-5.3 Codex?+
There is no overall benchmark winner: At least two independently verified, protocol-matched benchmarks are required for an overall winner.
Can Claude Opus 4.8 or GPT-5.3 Codex be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. Claude Opus 4.8 is not marked open weight; GPT-5.3 Codex is not marked open weight.
Can Claude Opus 4.8 and GPT-5.3 Codex understand images?+
Claude Opus 4.8 is documented with image input; GPT-5.3 Codex is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, Claude Opus 4.8 or GPT-5.3 Codex?+
Neither has a larger sourced maximum output. Claude Opus 4.8 is 128K and GPT-5.3 Codex is 128K.
Do Claude Opus 4.8 and GPT-5.3 Codex support reasoning and tool use?+
Claude Opus 4.8: reasoning, tool calling, and image input. GPT-5.3 Codex: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, Claude Opus 4.8 or GPT-5.3 Codex?+
Claude Opus 4.8 has 2 sourced provider routes; GPT-5.3 Codex has 2, a tie.
Which offers better value, Claude Opus 4.8 or GPT-5.3 Codex?+
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.