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DeepSeek-V4.1-Flash vs Step-3.5-Flash

DeepSeek-V4.1-Flash leads the LLM Stats Score 51.8 to 37.2. Step-3.5-Flash is 1.9x cheaper per token.

DeepSeek · StepFun · Updated for 2026

Which is better?

DeepSeek-V4.1-Flash leads the overall LLM Stats Score 51.8 to 37.2, ranking #12 overall.

On price, Step-3.5-Flash is roughly 1.9x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

DeepSeek-V4.1-Flash also accepts a larger context window (1,040,000 input tokens), making it the stronger choice for long documents and large codebases.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose DeepSeek-V4.1-Flash

  • overall performance matters — it scores 51.8 and ranks #12 on LLM Stats
  • your work emphasizes reasoning and coding — it leads those capability indexes
  • you process long inputs — it offers a 1,040,000 token context window
  • you want the most recent training data — it shipped Sep 2026

Choose Step-3.5-Flash

  • cost matters — it's about 1.9x cheaper per token

At a glance

The differences that matter most.

DeepSeek-V4.1-Flash
DeepSeek
Step-3.5-Flash
StepFun
Core performance indexes
LLM Stats Score
51.8
#12
37.2
#68
Reasoning
48.9
#17
37.2
#69
Coding
44.4
#5
20.5
#95
Agents
41.3
#4
15.5
#84
Cost, coverage & limits
Benchmark wins
—
—
Input price
$0.22 / M
$0.10 / M
Output price
$0.66 / M
$0.40 / M
Context window
1,040,000
65,536

Capability indexes

Additional strengths measured across groups of related public benchmarks

2 shared
Index
DeepSeek-V4.1-Flash
Step-3.5-Flash
Math
35.2#43
33.9#50
Tool use
35.1#2
13.3#96
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

20 reported for DeepSeek-V4.1-Flash · 7 for Step-3.5-Flash

No common benchmarks found

DeepSeek-V4.1-Flash and Step-3.5-Flashdon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

Step-3.5-Flash costs less

For input processing, DeepSeek-V4.1-Flash ($0.22/1M tokens) is 2.2x more expensive than Step-3.5-Flash ($0.10/1M tokens).

For output processing, DeepSeek-V4.1-Flash ($0.66/1M tokens) is 1.6x more expensive than Step-3.5-Flash ($0.40/1M tokens).

In conclusion, DeepSeek-V4.1-Flash is more expensive than Step-3.5-Flash.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Sun Sep 13 2026 • llm-stats.com
DeepSeek
DeepSeek-V4.1-Flash
Input tokens$0.22
Output tokens$0.66
Best providerFireworks
StepFun
Step-3.5-Flash
Input tokens$0.10
Output tokens$0.40
Best providerStepFun
Notice missing or incorrect data?Start an Issue→

Model Size

Parameter count comparison

567.2B diff

DeepSeek-V4.1-Flash has 567.2B more parameters than Step-3.5-Flash, making it 289.4% larger.

DeepSeek
DeepSeek-V4.1-Flash
763.2Bparameters
StepFun
Step-3.5-Flash
196.0Bparameters
763.2B
DeepSeek-V4.1-Flash
196.0B
Step-3.5-Flash

Context Window

Maximum input and output token capacity

DeepSeek-V4.1-Flash accepts 1,040,000 input tokens compared to Step-3.5-Flash's 65,536 tokens. DeepSeek-V4.1-Flash can generate longer responses up to 393,216 tokens, while Step-3.5-Flash is limited to 8,192 tokens.

DeepSeek
DeepSeek-V4.1-Flash
Input1,040,000 tokens
Output393,216 tokens
StepFun
Step-3.5-Flash
Input65,536 tokens
Output8,192 tokens
Sun Sep 13 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

DeepSeek-V4.1-Flash supports multimodal inputs, whereas Step-3.5-Flash does not.

DeepSeek-V4.1-Flash can handle both text and other forms of data like images, making it suitable for multimodal applications.

DeepSeek-V4.1-Flash

Text
Images
Audio
Video

Step-3.5-Flash

Text
Images
Audio
Video

License

Usage and distribution terms

DeepSeek-V4.1-Flash is licensed under MIT, while Step-3.5-Flash uses Apache 2.0.

License differences may affect how you can use these models in commercial or open-source projects.

DeepSeek-V4.1-Flash

MIT

Open weights

Step-3.5-Flash

Apache 2.0

Open weights

Release Timeline

When each model was launched

DeepSeek-V4.1-Flash was released on 2026-09-10, while Step-3.5-Flash was released on 2026-02-02.

DeepSeek-V4.1-Flash is 7 months newer than Step-3.5-Flash.

DeepSeek-V4.1-Flash

Sep 10, 2026

3 days ago

7mo newer
Step-3.5-Flash

Feb 2, 2026

7 months ago

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Provider Availability

DeepSeek-V4.1-Flash is available from Fireworks, DeepInfra, DeepSeek, Novita. Step-3.5-Flash is available from StepFun.

DeepSeek-V4.1-Flash

fireworks logo
Fireworks
Input Price:Input: $0.22/1MOutput Price:Output: $0.66/1M
deepinfra logo
Deepinfra
Input Price:Input: $0.30/1MOutput Price:Output: $1.20/1M
deepseek logo
DeepSeek
Input Price:Input: $0.30/1MOutput Price:Output: $1.20/1M
novita logo
Novita
Input Price:Input: $0.30/1MOutput Price:Output: $1.20/1M

Step-3.5-Flash

stepfun logo
StepFun
Input Price:Input: $0.10/1MOutput Price:Output: $0.40/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against DeepSeek-V4.1-Flash and Step-3.5-Flash side-by-side, then vote on the output you prefer.

DeepSeek-V4.1-Flash
✓ Preferred
Step-3.5-Flash
Open in Playground

FAQ

Common questions about DeepSeek-V4.1-Flash vs Step-3.5-Flash.

Which is better, DeepSeek-V4.1-Flash or Step-3.5-Flash?

DeepSeek-V4.1-Flash leads the LLM Stats Score 51.8 to 37.2. DeepSeek-V4.1-Flash is made by DeepSeek and Step-3.5-Flash is made by StepFun. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does DeepSeek-V4.1-Flash compare to Step-3.5-Flash in benchmarks?

DeepSeek-V4.1-Flash scores CodeForces: 100.0%, GPQA: 90.9%, Terminal-Bench 2.1: 90.6%, BabyVision: 89.6%, CyberGym: 88.1%. Step-3.5-Flash scores AIME 2025: 97.3%, Tau-bench: 88.2%, LiveCodeBench v6: 86.4%, IMO-AnswerBench: 85.4%, SWE-Bench Verified: 74.4%.

Is DeepSeek-V4.1-Flash cheaper than Step-3.5-Flash?

Step-3.5-Flash is 2.2x cheaper for input tokens. DeepSeek-V4.1-Flash costs $0.22/M input and $0.66/M output via fireworks. Step-3.5-Flash costs $0.10/M input and $0.40/M output via stepfun.

What are the context window sizes for DeepSeek-V4.1-Flash and Step-3.5-Flash?

DeepSeek-V4.1-Flash supports 1.0M tokens and Step-3.5-Flash supports 66K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between DeepSeek-V4.1-Flash and Step-3.5-Flash?

Key differences include LLM Stats Score (51.8 vs 37.2), context window (1.0M vs 66K), input pricing ($0.22 vs $0.10/M), multimodal support (yes vs no), licensing (MIT vs Apache 2.0). See the full comparison above for benchmark-by-benchmark results.

Who makes DeepSeek-V4.1-Flash and Step-3.5-Flash?

DeepSeek-V4.1-Flash is developed by DeepSeek and Step-3.5-Flash is developed by StepFun.

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