Qwen3.5-9B is $0.21 cheaper per 1M input tokens (84% lower; 6.25x difference).
API cost decision in 10 seconds
Qwen3.5-9B vs GPT-5.1-Codex-Mini
Pick Qwen3.5-9B for lower cost; pick GPT-5.1-Codex-Mini only if the larger context window matters more.
Page updated:
Data confirmed:
Prices normalized to USD per 1M tokens
Sample workload: 1M input + 500K output
Budget verdict
Pick Qwen3.5-9B for lower cost; pick GPT-5.1-Codex-Mini only if the larger context window matters more.
On the standard 1M input plus 500K output workload, Qwen3.5-9B is estimated at $0.11 vs $1.25 for GPT-5.1-Codex-Mini, saving $1.14 (90.8% lower).
Cost-first pickQwen3.5-9B
Context-first pickGPT-5.1-Codex-Mini
Sample savings$1.1490.8%
10x traffic gap$11.35
GPT-5.1-Codex-Mini has more context, but Qwen3.5-9B saves $1.14 on the standard workload. At 10x that traffic, the same price gap is about $11.35. Use the calculator below to replace the sample workload with your own token volume.
Cost sensitivity
Workload Sensitivity
Qwen3.5-9B stays cheaper across input-heavy, balanced, and output-heavy sample workloads.
| Workload shape | Token mix | Better pick | Qwen3.5-9B | GPT-5.1-Codex-Mini |
|---|---|---|---|---|
| Input-heavy / RAG | 5M input + 500K output | Qwen3.5-9B | $0.28 | $2.25 |
| Balanced workload | 1M input + 1M output | Qwen3.5-9B | $0.19 | $2.25 |
| Output-heavy chatbot | 1M input + 5M output | Qwen3.5-9B | $0.79 | $10.25 |
Qwen3.5-9B is $1.85 cheaper per 1M output tokens (92.5% lower; 13.3x difference).
GPT-5.1-Codex-Mini has 137.86K more context (1.53x larger).
Qwen3.5-9B is $1.14 cheaper on the standard workload (90.8% lower).
Estimate your workload cost
Your Workload Cost
This estimate uses normalized public API pricing per 1M tokens. It is a planning aid, not a billing quote. Verify provider pricing, limits, and terms before production use.
Quick Decision
Qwen3.5-9B has the lower input price; Qwen3.5-9B has the lower output price; GPT-5.1-Codex-Mini offers the larger context window. For the 1M input plus 500K output sample, Qwen3.5-9B is cheaper for the standard workload.
For a 1M input token plus 500K output token workload, the estimated API cost is $0.11 for Qwen3.5-9B and $1.25 for GPT-5.1-Codex-Mini.
Choose Qwen3.5-9B when you care most about lower input-token price, and lower output-token price.
Choose GPT-5.1-Codex-Mini when you care most about larger context window.
- On the standard 1M input plus 500K output workload, Qwen3.5-9B is estimated at $0.11 vs $1.25 for GPT-5.1-Codex-Mini, saving $1.14 (90.8% lower).
- Qwen3.5-9B is $1.14 cheaper on the standard workload (90.8% lower).
- Qwen3.5-9B is $0.21 cheaper per 1M input tokens (84% lower; 6.25x difference).
- Qwen3.5-9B is $1.85 cheaper per 1M output tokens (92.5% lower; 13.3x difference).
- GPT-5.1-Codex-Mini has 137.86K more context (1.53x larger).
| Feature | Qwen3.5-9B (Qwen) | GPT-5.1-Codex-Mini (OpenAI) |
|---|---|---|
| Input Price prompt tokens per 1M | $0.04 | $0.25 |
| Completion Price per 1M tokens | $0.15 | $2 |
| Sample Workload Cost 1M input + 500K output | $0.11 | $1.25 |
| Context Window | 262.14K | 400K |
| Release Date |
Use-Case Decision Matrix
| Use case | Better pick | Why |
|---|---|---|
| Budget-constrained production | Qwen3.5-9B | On the standard 1M input plus 500K output workload, Qwen3.5-9B is estimated at $0.11 vs $1.25 for GPT-5.1-Codex-Mini, saving $1.14 (90.8% lower). |
| High-volume input processing | Qwen3.5-9B | Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill. |
| Long responses and chatbots | Qwen3.5-9B | Lower output-token price matters most when assistants generate many completion tokens. |
| RAG or long-document work | GPT-5.1-Codex-Mini | A larger context window leaves more room for retrieved passages, conversation history, or source files. |
Related Alternatives
- Qwen3 Next 80B A3B Instruct (free) can replace Qwen3.5-9B when lower sample workload cost matters most: $0.
- Qwen3 Coder 480B A35B (free) can replace Qwen3.5-9B when lower sample workload cost matters most: $0.
- Qwen2.5 7B Instruct can replace Qwen3.5-9B when lower sample workload cost matters most: $0.09.
- gpt-oss-120b (free) can replace GPT-5.1-Codex-Mini when lower sample workload cost matters most: $0.
- Llama 4 Scout offers 10M context with $0.23 sample workload cost.
- Owl Alpha offers 1.05M context with $0 sample workload cost.
- DeepSeek V4 Flash offers 1.05M context with $0.2 sample workload cost.
- DeepSeek V4 Pro offers 1.05M context with $0.87 sample workload cost.
- DeepSeek V4 Flash · DeepSeek · #1
- Hy3 preview · Tencent · #2
- Claude Opus 4.7 · Anthropic · #3
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Open OpenAI modelsQwen3.5-9B is a multimodal foundation model from the Qwen3.5 family, designed to deliver strong reasoning, coding, and visual understanding in an efficient 9B-parameter architecture. It uses a unified vision-language design...
GPT-5.1-Codex-Mini is a smaller and faster version of GPT-5.1-Codex