Models / GPT-5.1-Codex
GPT-5.1-Codex
22nd most intelligent of the 34 models priced $3–10 per million tokens. Mid-field among models available today on every use case measured so far.
- Price per million tokens
- $1.25 in · $10.00 out
Typical host on OpenRouter, 7 Oct 2026 · compare prices - Speed
- Not measured
- Intelligence Index
- 23.7
Artificial Analysis - Spring Prompt overall
- Not ranked yet
needs our benchmarks and two groups of results - Developer
- OpenAI, based in the US
Weights not published - Released
- Not recorded
400,000 tokens of context
Where it stands among the models you could choose
Ranked only among models available today (those you can call through OpenRouter), in the groups people choose between: the same price band, similar intelligence, the same speed, developers based in the same place. Retired models are left out.
| Among | Intelligence Index | Spring Prompt overall | Price | Speed |
|---|---|---|---|---|
| Models available today | 70th of 195Claude Opus 5.5 | – | 179th of 221Mistral Nemo | – |
| Models priced $3–10 per million tokens | 22nd of 34Claude Opus 5.5 | – | the group | – |
| Models with similar intelligence | the group | – | 33rd of 39MiMo-V2.5 | – |
| Models from developers based in the US | 42nd of 93Claude Opus 5.5 | – | 64th of 103Llama 3.1 8B Instruct | – |
The name under each rank is the leader of that group. Price is the developer's list price (or the typical OpenRouter host where we haven't read one) for three input tokens to one output; intelligence and speed are from Artificial Analysis (data sourced from Artificial Analysis); "similar intelligence" means within 4 points on its Intelligence Index. Developer locations are where each company is based, not where a model is served. Groups under 3 models are not ranked.
How good is it, and for what?
Each use case ranks the available models its benchmarks measured, then those priced $3–10 per million tokens. The bar shows where it falls in that field, best to the right. Open a row for the results behind it.
Product listingsTurning a sparse product feed and photos into listings that can go live
- CatalogBench: has not measured this model.
Decks from an analysisTurning a finished analysis into a deck you could present as it is
- DeckBench: has not measured this model.
Marketing planningPlanning a year of ad spend without overspending
- ROASBench: has not measured this model.
Agents and tool useMulti-step tasks with tools: support desks, coding agents, function calls
- tau2-bench: has not measured this model.
- Berkeley Function Calling Leaderboard (BFCL) V4: has not measured this model.
- OpenHands Index: has not measured this model.
- Microsoft STATE-Bench: has not measured this model.
- Artificial Analysis: has not measured this model.
- Vending-Bench 2: has not measured this model.
Professional workReal tasks from banking, consulting and law, business documents and freelance projects
- APEX-Agents: has not measured this model.
- GDP.pdf: has not measured this model.
- Remote Labor Index: has not measured this model.
Reasoning and knowledgeHard questions across science, maths and general knowledge
| Benchmark | GPT-5.1-Codex | Rank among available | Best available |
|---|---|---|---|
| Artificial AnalysisArtificial Analysis: Artificial Analysis Intelligence Index · reported | 23.7 | 70th of 195 | Claude Opus 5.5 57.6 |
| Artificial AnalysisArtificial Analysis: Humanity's Last Exam · reported | 25.7% | 78th of 194 | Claude Opus 5.5 61.4% |
| Artificial AnalysisArtificial Analysis: GPQA Diamond · reported | 86.0% | 62nd of 185 | GPT-6 Astra 96.3% |
WritingWhat people prefer in blind comparisons, and judged writing quality
- Arena (formerly LMArena): has not measured this model.
- UGI Leaderboard: has not measured this model.
Sticking to the factsSummarising without inventing things, and factual answers
- Vectara Hallucination Leaderboard: has not measured this model.
- Arena (formerly LMArena): has not measured this model.
- SimpleQA Verified (Epoch AI): has not measured this model.
Speed under pressureGood decisions against a real clock (fast chess)
- BulletBench: has not measured this model.
Against the alternatives
The models you would most likely weigh it against: the leaders of the groups above.
| GPT-5.1-Codex | Claude Opus 5.5 most intelligent at $3–10 per million tokens | MiMo-V2.5 cheapest with similar intelligence | GPT-6.1 Sol leads overall | GPT-6 Astra near the top overall | |
|---|---|---|---|---|---|
| Price per million tokens | $3.44 | $8.00 | $0.21 | $4.00 | $20.00 |
| Tokens a second | – | 97 | – | 57 | 52 |
| Intelligence Index | 23.7 | 57.6 | 25.2 | 51.8 | 52.7 |
| Spring Prompt overall | – | 82 | – | 88 | 78 |
| Rank among available models, by use case | |||||
| Product listings | – | 6th | – | 2nd | 1st |
| Decks from an analysis | – | 5th | – | 3rd | 1st |
| Marketing planning | – | 5th | – | – | 1st |
| Agents and tool use | – | 2nd | 95th | 3rd | 4th |
| Professional work | – | 3rd | – | 9th | 5th |
| Reasoning and knowledge | 75th of 195 | 1st | 74th | 5th | 3rd |
| Writing | – | 4th | 60th | – | 17th |
| Sticking to the facts | – | 6th | 83rd | 2nd | 27th |
| Speed under pressure | – | – | – | – | 14th |
Shaded figures are better than GPT-5.1-Codex's. A dash means no result.
Where it has been measured
- Artificial Analysis7 results
- BulletBenchNot measured
- CatalogBenchNot measured
- DeckBenchNot measured
- ROASBenchNot measured
- APEX-AgentsNot measured
- Arena (formerly LMArena)Not measured
- Berkeley Function Calling Leaderboard (BFCL) V4Not measured
- GDP.pdfNot measured
- Microsoft STATE-BenchNot measured
- OpenHands IndexNot measured
- Remote Labor IndexNot measured
- SimpleQA Verified (Epoch AI)Not measured
- tau2-benchNot measured
- UGI LeaderboardNot measured
- Vectara Hallucination LeaderboardNot measured
- Vending-Bench 2Not measured
Every result
7 published results from 1 source, each in the source's own units, with the configuration that produced it.
Artificial Analysis · reported by Artificial Analysis · 7 results
| Measure | Value | Rank | Configuration | Dated |
|---|---|---|---|---|
| Artificial Analysis: Artificial Analysis Intelligence Indexindex score, higher is better | 23.7 | 159 of 402 | GPT-5.1-Codex (high) | 7 Oct 2026 |
| Artificial Analysis: GPQA Diamond% of questions, higher is better | 86.0% | 113 of 359 | GPT-5.1-Codex (high) | 7 Oct 2026 |
| Artificial Analysis: Humanity's Last Exam% of questions, higher is better | 25.7% | 159 of 400 | GPT-5.1-Codex (high) | 7 Oct 2026 |
| Artificial Analysis: IFBench% of instructions, higher is better | 70.0% | 65 of 288 | GPT-5.1-Codex (high) | 7 Oct 2026 |
| Artificial Analysis: Long-context reasoning (AA-LCR)% of questions, higher is better | 69.3% | 190 of 388 | GPT-5.1-Codex (high) | 7 Oct 2026 |
| Artificial Analysis: Terminal-Bench Hard% of tasks, higher is better | 34.8% | 77 of 282 | GPT-5.1-Codex (high) | 7 Oct 2026 |
| Artificial Analysis: τ²-bench telecom% of tasks, higher is better | 83.0% | 95 of 286 | GPT-5.1-Codex (high) | 7 Oct 2026 |
Not shown: Not business work, and a blend: read the parts for any one task.