Step 3.5 Flash
$0.10 per 1M input tokens and $0.30 per 1M output tokens · 262K context · tools, reasoning, open weights.
Prices checked Oct 21, 2026 · tracked by LLM Cost Index since Oct 21, 2026
$0.10
input / 1M tokens
$0.30
output / 1M tokens
262K
context window
66K
max output
17
Artificial Analysis intelligence index
What Step 3.5 Flash costs per month
Estimated monthly bill for typical workloads. Try your own numbers in the cost calculator.
| Workload | Per month |
|---|---|
| Customer chatbot 1,000 conversations a day, 8 turns each | $61.20 |
| Document Q&A (RAG) 500 questions a day over retrieved documents | $11.25 |
| Coding / tool-using agent 200 tasks a day, long tool-heavy contexts | $43.20 |
| Content generation 30 long articles a day | $0.945 |
| Classification / extraction 100,000 short items a day | $103 |
Price history
We started tracking Step 3.5 Flash on Oct 21, 2026; the chart appears as soon as there is a second data point. See all recent price changes.
Cheaper alternatives to Step 3.5 Flash
Models with the same tool calling for at least 20% less (3:1 input/output mix), most capable first.
| Model | Input / 1M | Output / 1M | Context | Capabilities |
|---|---|---|---|---|
| GLM 5.3 Flash Z.ai | $0.041 | $0.12 | 1.05M | visiontoolsreasoningJSONopen weights |
| Ling 3.1 Flash inclusionAI | $0.075 | $0.225 | 262K | toolsreasoningJSON |
| Ling 3.0 Flash VL inclusionAI | $0.06 | $0.18 | 131K | visiontoolsreasoningJSONopen weights |
| DeepSeek V4 Flash 0423 DeepSeek | $0.091 | $0.182 | 1.05M | toolsreasoningJSONopen weights |
| Solar Mini 4 Upstage | $0.05 | $0.20 | 524K | toolsreasoningJSON |
How to pay less for Step 3.5 Flash
For a customer chatbot (1,000 conversations a day, 8 turns each) that costs $61.20 a month at list price without caching:
| Option | Per month | You save |
|---|---|---|
| Move to GLM 5.3 Flash (similar capabilities) | $16.82 | $44.38 (73%) |
Other workloads: cut-your-bill tool for Step 3.5 Flash.
Specifications
| Model ID | stepfun/step-3.5-flash |
| Input | text |
| Output | text |
| Tool calling | Yes |
| Structured output | No |
| Reasoning mode | Yes |
| Open weights | Yes — stepfun-ai/Step-3.5-Flash |
| Released | Jan 29, 2026 |
FAQ
- How much does Step 3.5 Flash cost?
- $0.10 per million input tokens and $0.30 per million output tokens. Prices as of Oct 21, 2026.
- What is the context window of Step 3.5 Flash?
- 262K tokens, with up to 66K output tokens per response.
- Does Step 3.5 Flash support images, tools and structured output?
- Images as input: no. Tool calling: yes. Structured (JSON) output: no. Reasoning mode: yes.
- What are cheaper alternatives to Step 3.5 Flash?
- Models with the same key capabilities for at least 20% less include GLM 5.3 Flash ($0.041 / $0.12), Ling 3.1 Flash ($0.075 / $0.225), Ling 3.0 Flash VL ($0.06 / $0.18).
More from Stepfun: all Stepfun models · how we collect prices