GPT-5.1-Codex-Mini is $0.02 cheaper per 1M input tokens (7.4% lower; 1.08x difference).
API cost decision in 10 seconds
DeepSeek V3.1 Terminus vs GPT-5.1-Codex-Mini
Pick DeepSeek V3.1 Terminus 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 DeepSeek V3.1 Terminus 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, DeepSeek V3.1 Terminus is estimated at $0.74 vs $1.25 for GPT-5.1-Codex-Mini, saving $0.51 (40.4% lower).
Cost-first pickDeepSeek V3.1 Terminus
Context-first pickGPT-5.1-Codex-Mini
Sample savings$0.5140.4%
10x traffic gap$5.05
GPT-5.1-Codex-Mini has more context, but DeepSeek V3.1 Terminus saves $0.51 on the standard workload. At 10x that traffic, the same price gap is about $5.05. Use the calculator below to replace the sample workload with your own token volume.
Cost sensitivity
Workload Sensitivity
DeepSeek V3.1 Terminus stays cheaper across input-heavy, balanced, and output-heavy sample workloads.
| Workload shape | Token mix | Better pick | DeepSeek V3.1 Terminus | GPT-5.1-Codex-Mini |
|---|---|---|---|---|
| Input-heavy / RAG | 5M input + 500K output | DeepSeek V3.1 Terminus | $1.83 | $2.25 |
| Balanced workload | 1M input + 1M output | DeepSeek V3.1 Terminus | $1.22 | $2.25 |
| Output-heavy chatbot | 1M input + 5M output | DeepSeek V3.1 Terminus | $5.02 | $10.25 |
DeepSeek V3.1 Terminus is $1.05 cheaper per 1M output tokens (52.5% lower; 2.11x difference).
GPT-5.1-Codex-Mini has 236.16K more context (2.44x larger).
DeepSeek V3.1 Terminus is $0.51 cheaper on the standard workload (40.4% 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
GPT-5.1-Codex-Mini has the lower input price; DeepSeek V3.1 Terminus has the lower output price; GPT-5.1-Codex-Mini offers the larger context window. For the 1M input plus 500K output sample, DeepSeek V3.1 Terminus is cheaper for the standard workload.
For a 1M input token plus 500K output token workload, the estimated API cost is $0.74 for DeepSeek V3.1 Terminus and $1.25 for GPT-5.1-Codex-Mini.
Choose DeepSeek V3.1 Terminus when you care most about lower output-token price.
Choose GPT-5.1-Codex-Mini when you care most about lower input-token price, and larger context window.
- On the standard 1M input plus 500K output workload, DeepSeek V3.1 Terminus is estimated at $0.74 vs $1.25 for GPT-5.1-Codex-Mini, saving $0.51 (40.4% lower).
- DeepSeek V3.1 Terminus is $0.51 cheaper on the standard workload (40.4% lower).
- GPT-5.1-Codex-Mini is $0.02 cheaper per 1M input tokens (7.4% lower; 1.08x difference).
- DeepSeek V3.1 Terminus is $1.05 cheaper per 1M output tokens (52.5% lower; 2.11x difference).
- GPT-5.1-Codex-Mini has 236.16K more context (2.44x larger).
| Feature | DeepSeek V3.1 Terminus (DeepSeek) | GPT-5.1-Codex-Mini (OpenAI) |
|---|---|---|
| Input Price prompt tokens per 1M | $0.27 | $0.25 |
| Completion Price per 1M tokens | $0.95 | $2 |
| Sample Workload Cost 1M input + 500K output | $0.74 | $1.25 |
| Context Window | 163.84K | 400K |
| Release Date | ||
| Popularity | #91 | #141 |
Use-Case Decision Matrix
| Use case | Better pick | Why |
|---|---|---|
| Budget-constrained production | DeepSeek V3.1 Terminus | On the standard 1M input plus 500K output workload, DeepSeek V3.1 Terminus is estimated at $0.74 vs $1.25 for GPT-5.1-Codex-Mini, saving $0.51 (40.4% lower). |
| High-volume input processing | GPT-5.1-Codex-Mini | Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill. |
| Long responses and chatbots | DeepSeek V3.1 Terminus | 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
- DeepSeek V4 Flash (free) can replace DeepSeek V3.1 Terminus when lower sample workload cost matters most: $0.
- DeepSeek V4 Flash can replace DeepSeek V3.1 Terminus when lower sample workload cost matters most: $0.2.
- R1 Distill Qwen 32B can replace DeepSeek V3.1 Terminus when lower sample workload cost matters most: $0.43.
- DeepSeek V3.2 can replace DeepSeek V3.1 Terminus when lower sample workload cost matters most: $0.44.
- 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
- Claude Sonnet 4.6 · Anthropic · #4
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Open OpenAI modelsDeepSeek-V3.1 Terminus is an update to [DeepSeek V3.1](/deepseek/deepseek-chat-v3.1) that maintains the model's original capabilities while addressing issues reported by users, including language consistency and agent capabilities, further optimizing the model's...
GPT-5.1-Codex-Mini is a smaller and faster version of GPT-5.1-Codex