GPT-5.1-Codex-Mini
by OpenAI · openai/gpt-5.1-codex-mini · #188 cheapest of 422 paid models
Prices updated Sep 19, 2026, 6:21 PM UTC · refreshed hourly
GPT-5.1-Codex-Mini is a smaller and faster version of GPT-5.1-Codex
Compare vs:Claude Sonnet 5Claude Opus 4.6Claude Haiku 4.5Gemini 3.6 Flash
Pricing
Input
$0.25
per 1M tokens
Output
$2.00
per 1M tokens
Blended (3:1)
$0.688
3 input : 1 output
Cache read
$0.03
per 1M cached tokens
Cache write
—
per 1M tokens
Cache & batch economics
Effective prices for GPT-5.1-Codex-Mini with prompt caching.
| Cache hit rate | Effective blended $/1M | Example request* | vs no cache |
|---|---|---|---|
| 0% | $0.688 | $0.0275 | — |
| 50% | $0.605 | $0.0165 | −40% |
| 90% | $0.539 | $0.0077 | −72% |
*Example: 100K sticky context + 2K new input + 1K output. Batch discount is an approximate 50% off list rates for this provider’s batch API. Confirm on the vendor’s pricing page.
What a request costs
| Workload | Input tokens | Output tokens | Cost / request | Cost / 1K requests |
|---|---|---|---|---|
| Short chat message | 500 | 300 | $0.000725 | $0.725 |
| Document summary | 8,000 | 1,000 | $0.004 | $4.00 |
| Codebase question (RAG) | 30,000 | 2,000 | $0.0115 | $11.50 |
| Long-context analysis | 150,000 | 5,000 | $0.0475 | $47.50 |
Performance
Intelligence Index
20.4
AA composite quality
Coding Index
—
Math Index
91.7
Agentic Index
—
Output speed
0 tok/s
median
Time to first token
0s
median
Time to first answer
0s
after reasoning tokens
Artificial Analysis benchmarks
| Benchmark | Score |
|---|---|
| MMLU-Pro | 82.0% |
| GPQA Diamond | 81.3% |
| Humanity's Last Exam | 18.5% |
| LiveCodeBench | 83.6% |
| AIME 2025 | 91.7% |
| IFBench | 67.9% |
| AA-LCR (Long Context Reasoning) | 66.7% |
| Terminal-Bench Hard | 33.3% |
| τ²-Bench (Telecom) | 62.9% |
Design Arena Elo
| Category | Elo |
|---|---|
| Website | 1,123 |
| UI components | 1,096 |
| Data viz | 1,112 |
| SVG | 1,002 |
| 3D | 1,017 |
| Game dev | 1,116 |
| Code categories | 1,109 |
| ASCII art | 1,123 |
Specs
Context window
400K
tokens
Max output
128K
tokens
Input modalities
image, text
Tokenizer
GPT