gpt-oss-120b is $0.06 cheaper per 1M input tokens (61% lower; 2.56x difference).
API cost decision in 10 seconds
🔥Step 3.5 Flash vs 🔥gpt-oss-120b
Pick gpt-oss-120b for lower cost; pick Step 3.5 Flash only if the larger context window matters more.
Pricing data updated:
Prices normalized to USD per 1M tokens
Sample workload: 1M input + 500K output
Budget verdict
Pick gpt-oss-120b for lower cost; pick Step 3.5 Flash only if the larger context window matters more.
On the standard 1M input plus 500K output workload, gpt-oss-120b is estimated at $0.13 vs $0.25 for Step 3.5 Flash, saving $0.12 (48.4% lower).
Cost-first pickgpt-oss-120b
Context-first pickStep 3.5 Flash
Sample savings$0.1248.4%
10x traffic gap$1.21
Step 3.5 Flash has more context, but gpt-oss-120b saves $0.12 on the standard workload. At 10x that traffic, the same price gap is about $1.21. Use the calculator below to replace the sample workload with your own token volume.
gpt-oss-120b is $0.12 cheaper per 1M output tokens (40% lower; 1.67x difference).
Step 3.5 Flash has 131.07K more context (2x larger).
gpt-oss-120b is $0.12 cheaper on the standard workload (48.4% 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-oss-120b has the lower input price; gpt-oss-120b has the lower output price; Step 3.5 Flash offers the larger context window. For the 1M input plus 500K output sample, gpt-oss-120b is cheaper for the standard workload.
For a 1M input token plus 500K output token workload, the estimated API cost is $0.25 for Step 3.5 Flash and $0.13 for gpt-oss-120b.
Choose Step 3.5 Flash when you care most about larger context window.
Choose gpt-oss-120b when you care most about lower input-token price, and lower output-token price.
- On the standard 1M input plus 500K output workload, gpt-oss-120b is estimated at $0.13 vs $0.25 for Step 3.5 Flash, saving $0.12 (48.4% lower).
- gpt-oss-120b is $0.12 cheaper on the standard workload (48.4% lower).
- gpt-oss-120b is $0.06 cheaper per 1M input tokens (61% lower; 2.56x difference).
- gpt-oss-120b is $0.12 cheaper per 1M output tokens (40% lower; 1.67x difference).
- Step 3.5 Flash has 131.07K more context (2x larger).
| Feature | 🔥Step 3.5 Flash (StepFun) | 🔥gpt-oss-120b (OpenAI) |
|---|---|---|
| Input Price prompt tokens per 1M | $0.1 | $0.039 |
| Completion Price per 1M tokens | $0.3 | $0.18 |
| Sample Workload Cost 1M input + 500K output | $0.25 | $0.13 |
| Context Window | 262.14K | 131.07K |
| Release Date | 2026-01-29 | 2025-08-05 |
| Popularity Rank current rank | #15 | #20 |
Use-Case Decision Matrix
| Use case | Better pick | Why |
|---|---|---|
| Budget-constrained production | gpt-oss-120b | On the standard 1M input plus 500K output workload, gpt-oss-120b is estimated at $0.13 vs $0.25 for Step 3.5 Flash, saving $0.12 (48.4% lower). |
| High-volume input processing | gpt-oss-120b | Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill. |
| Long responses and chatbots | gpt-oss-120b | Lower output-token price matters most when assistants generate many completion tokens. |
| RAG or long-document work | Step 3.5 Flash | A larger context window leaves more room for retrieved passages, conversation history, or source files. |
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