Qwen3.5 Plus 2026-04-20 is $0.95 cheaper per 1M input tokens (76% lower; 4.17x difference).
API cost decision in 10 seconds
Qwen3.5 Plus 2026-04-20 vs GPT-5.1-Codex
Pick Qwen3.5 Plus 2026-04-20 when budget and context both matter.
Page updated:
Data confirmed:
Prices normalized to USD per 1M tokens
Sample workload: 1M input + 500K output
Budget verdict
Pick Qwen3.5 Plus 2026-04-20 when budget and context both matter.
On the standard 1M input plus 500K output workload, Qwen3.5 Plus 2026-04-20 is estimated at $1.2 vs $6.25 for GPT-5.1-Codex, saving $5.05 (80.8% lower).
Cost-first pickQwen3.5 Plus 2026-04-20
Context-first pickQwen3.5 Plus 2026-04-20
Sample savings$5.0580.8%
10x traffic gap$50.5
Qwen3.5 Plus 2026-04-20 is cheaper on the standard workload and also has the larger context window. At 10x that traffic, the same price gap is about $50.5. Use the calculator below to replace the sample workload with your own token volume.
Cost sensitivity
Workload Sensitivity
Qwen3.5 Plus 2026-04-20 stays cheaper across input-heavy, balanced, and output-heavy sample workloads.
| Workload shape | Token mix | Better pick | Qwen3.5 Plus 2026-04-20 | GPT-5.1-Codex |
|---|---|---|---|---|
| Input-heavy / RAG | 5M input + 500K output | Qwen3.5 Plus 2026-04-20 | $2.4 | $11.25 |
| Balanced workload | 1M input + 1M output | Qwen3.5 Plus 2026-04-20 | $2.1 | $11.25 |
| Output-heavy chatbot | 1M input + 5M output | Qwen3.5 Plus 2026-04-20 | $9.3 | $51.25 |
Qwen3.5 Plus 2026-04-20 is $8.2 cheaper per 1M output tokens (82% lower; 5.56x difference).
Qwen3.5 Plus 2026-04-20 has 600K more context (2.5x larger).
Qwen3.5 Plus 2026-04-20 is $5.05 cheaper on the standard workload (80.8% 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 Plus 2026-04-20 has the lower input price; Qwen3.5 Plus 2026-04-20 has the lower output price; Qwen3.5 Plus 2026-04-20 offers the larger context window. For the 1M input plus 500K output sample, Qwen3.5 Plus 2026-04-20 is cheaper for the standard workload.
For a 1M input token plus 500K output token workload, the estimated API cost is $1.2 for Qwen3.5 Plus 2026-04-20 and $6.25 for GPT-5.1-Codex.
Choose Qwen3.5 Plus 2026-04-20 when you care most about lower input-token price, lower output-token price, and larger context window.
Choose GPT-5.1-Codex when its provider, model quality, latency, or availability is more important than the numeric price/context winner.
- On the standard 1M input plus 500K output workload, Qwen3.5 Plus 2026-04-20 is estimated at $1.2 vs $6.25 for GPT-5.1-Codex, saving $5.05 (80.8% lower).
- Qwen3.5 Plus 2026-04-20 is $5.05 cheaper on the standard workload (80.8% lower).
- Qwen3.5 Plus 2026-04-20 is $0.95 cheaper per 1M input tokens (76% lower; 4.17x difference).
- Qwen3.5 Plus 2026-04-20 is $8.2 cheaper per 1M output tokens (82% lower; 5.56x difference).
- Qwen3.5 Plus 2026-04-20 has 600K more context (2.5x larger).
| Feature | Qwen3.5 Plus 2026-04-20 (Qwen) | GPT-5.1-Codex (OpenAI) |
|---|---|---|
| Input Price prompt tokens per 1M | $0.3 | $1.25 |
| Completion Price per 1M tokens | $1.8 | $10 |
| Sample Workload Cost 1M input + 500K output | $1.2 | $6.25 |
| Context Window | 1M | 400K |
| Release Date |
Use-Case Decision Matrix
| Use case | Better pick | Why |
|---|---|---|
| Budget-constrained production | Qwen3.5 Plus 2026-04-20 | On the standard 1M input plus 500K output workload, Qwen3.5 Plus 2026-04-20 is estimated at $1.2 vs $6.25 for GPT-5.1-Codex, saving $5.05 (80.8% lower). |
| High-volume input processing | Qwen3.5 Plus 2026-04-20 | Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill. |
| Long responses and chatbots | Qwen3.5 Plus 2026-04-20 | Lower output-token price matters most when assistants generate many completion tokens. |
| RAG or long-document work | Qwen3.5 Plus 2026-04-20 | A larger context window leaves more room for retrieved passages, conversation history, or source files. |
Related Alternatives
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- Qwen2.5 7B Instruct can replace Qwen3.5 Plus 2026-04-20 when lower sample workload cost matters most: $0.09.
- Qwen3.5-9B can replace Qwen3.5 Plus 2026-04-20 when lower sample workload cost matters most: $0.11.
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