StepFunopen weightsreasoningStep 3.5 Flash pricing
$0.10 per 1M input tokens and $0.30 per 1M output tokens. In real work that is 0.05¢ per chat answer and 0.18¢ to summarize a 20-page PDF.
What Step 3.5 Flash costs per task
Token counts estimated from a measured model of the same lab (GLM 5.3 Flash), rescaled by tokenizer. Reasoning tokens are billed as output.
| Task | Cost | Tokens used | Price rank | Basis |
|---|---|---|---|---|
| Answer a chat question | 0.05¢$0.54 / 1,000 | 47 in · 389 out · 1,391 reasoning | 65 of 336 | estimated |
| Reply to a customer email | 0.01¢$0.10 / 1,000 | 264 in · 233 out · 24 reasoning | 25 of 336 | estimated |
| Write a 1,500-word blog post | 0.21¢$2.08 / 1,000 | 61 in · 2,167 out · 4,749 reasoning | 61 of 336 | estimated |
| Write 10 product descriptions | 0.21¢$2.14 / 1,000 | 288 in · 1,097 out · 5,940 reasoning | 79 of 336 | estimated |
| Translate 1,000 words | 0.32¢$3.18 / 1,000 | 1,326 in · 1,389 out · 8,761 reasoning | 128 of 336 | estimated |
| Proofread one page (500 words) | 0.03¢$0.31 / 1,000 | 727 in · 640 out · 155 reasoning | 27 of 336 | estimated |
| Summarize a 20-page PDF | 0.18¢$1.84 / 1,000 | 12,956 in · 542 out · 1,270 reasoning | 64 of 336 | estimated |
| Extract data from an invoice | 0.03¢$0.35 / 1,000 | 389 in · 453 out · 576 reasoning | 32 of 336 | estimated |
| Analyze a 200-row spreadsheet | ≥0.53¢$5.29 / 1,000 | 4,885 in · 0 out · 16,000 reasoning | 73 of 336 | estimated |
| Answer from 5 retrieved documents (RAG) | 0.10¢$0.96 / 1,000 | 3,702 in · 273 out · 1,697 reasoning | 51 of 336 | estimated |
| Classify 100 support tickets | 0.25¢$2.48 / 1,000 | 1,277 in · 439 out · 7,411 reasoning | 91 of 336 | estimated |
| Review 500 lines of code | ≥0.53¢$5.25 / 1,000 | 4,518 in · 1 out · 15,998 reasoning | 92 of 336 | estimated |
| Write a SQL query | 0.05¢$0.49 / 1,000 | 127 in · 471 out · 1,123 reasoning | 42 of 336 | estimated |
| Run a 50-step coding agent | 24¢$236 / 1,000 | 2,233,025 in · 14,970 out · 28,800 reasoning | 112 of 336 | modeled |
Price at every provider
List prices per 1M tokens (input / output) at each host serving Step 3.5 Flash through OpenRouter today. Hosts can differ in quantization, context and speed.
| Provider | Input / output | Cached input | Context | Uptime |
|---|---|---|---|---|
 SiliconFlowfp8 | $0.10 / $0.30 | - | 262K | 100% |
Price history
First seen in our price history on Feb 15, 2026 at $0.10 input / $0.30 output. Since then the output price moved from $0.30 to $0.30 per 1M tokens (2 changes).
FAQ
How much does Step 3.5 Flash cost?
Step 3.5 Flash costs $0.10 per 1 million input tokens and $0.30 per 1 million output tokens (list price on Oct 18, 2026). In practice one chat answer costs about 0.05¢ and summarizing a 20-page PDF about 0.18¢.
Where is Step 3.5 Flash cheapest?
Among 1 providers we track, the lowest list price today is at SiliconFlow: $0.10 input and $0.30 output per 1M tokens.
Does Step 3.5 Flash charge for reasoning tokens?
Yes. Reasoning (thinking) tokens are billed as output tokens. That is why the cost per task can be much higher than the visible answer suggests - our task costs include them.
Is the Step 3.5 Flash cost per task measured or estimated?
Estimated: Step 3.5 Flash was not run directly. Tokens come from GLM 5.3 Flash and are rescaled by the tokenizer of StepFun. Real usage can differ.