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GPT-4o vs Step-3.5-Flash

Step-3.5-Flash leads the LLM Stats Score 37.3 to 11.7. Step-3.5-Flash is 25.0x cheaper per token.

OpenAI · StepFun · Updated for 2026

Which is better?

Step-3.5-Flash leads the overall LLM Stats Score 37.3 to 11.7, ranking #61 overall.

On price, Step-3.5-Flash is roughly 25.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

GPT-4o also accepts a larger context window (128,000 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 GPT-4o

  • you process long inputs — it offers a 128,000 token context window

Choose Step-3.5-Flash

  • overall performance matters — it scores 37.3 and ranks #61 on LLM Stats
  • your work emphasizes reasoning — it leads those capability indexes
  • cost matters — it's about 25.0x cheaper per token
  • you want the most recent training data — it shipped Feb 2026
  • you need open weights you can self-host or fine-tune

At a glance

The differences that matter most.

GPT-4o
OpenAI
Step-3.5-Flash
StepFun
Core performance indexes
LLM Stats Score
11.7
#241
37.3
#61
Reasoning
12.3
#230
37.3
#62
Coding
11.8
#139
20.4
#88
Cost, coverage & limits
Benchmark wins
—
—
Input price
$2.50 / M
$0.10 / M
Output price
$10.00 / M
$0.40 / M
Context window
128,000
65,536

Capability indexes

Additional strengths measured across groups of related public benchmarks

1 shared
Index
GPT-4o
Step-3.5-Flash
Math
18.3#171
33.8#50
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

8 reported for GPT-4o · 7 for Step-3.5-Flash

No common benchmarks found

GPT-4o 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, GPT-4o ($2.50/1M tokens) is 25.0x more expensive than Step-3.5-Flash ($0.10/1M tokens).

For output processing, GPT-4o ($10.00/1M tokens) is 25.0x more expensive than Step-3.5-Flash ($0.40/1M tokens).

In conclusion, GPT-4o is more expensive than Step-3.5-Flash.*

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

Lowest available price from all providers
Mon Aug 31 2026 • llm-stats.com
OpenAI
GPT-4o
Input tokens$2.50
Output tokens$10.00
Best providerAzure
StepFun
Step-3.5-Flash
Input tokens$0.10
Output tokens$0.40
Best providerStepFun
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

GPT-4o accepts 128,000 input tokens compared to Step-3.5-Flash's 65,536 tokens. Step-3.5-Flash can generate longer responses up to 8,192 tokens, while GPT-4o is limited to 4,096 tokens.

OpenAI
GPT-4o
Input128,000 tokens
Output4,096 tokens
StepFun
Step-3.5-Flash
Input65,536 tokens
Output8,192 tokens
Mon Aug 31 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

GPT-4o supports multimodal inputs, whereas Step-3.5-Flash does not.

GPT-4o can handle both text and other forms of data like images, making it suitable for multimodal applications.

GPT-4o

Text
Images
Audio
Video

Step-3.5-Flash

Text
Images
Audio
Video

License

Usage and distribution terms

GPT-4o is licensed under a proprietary license, 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.

GPT-4o

Proprietary

Closed source

Step-3.5-Flash

Apache 2.0

Open weights

Release Timeline

When each model was launched

GPT-4o was released on 2024-05-13, while Step-3.5-Flash was released on 2026-02-02.

Step-3.5-Flash is 21 months newer than GPT-4o.

GPT-4o

May 13, 2024

2.3 years ago

Step-3.5-Flash

Feb 2, 2026

7 months ago

1.7yr newer

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

GPT-4o is available from Azure, OpenAI. Step-3.5-Flash is available from StepFun.

GPT-4o

azure logo
Azure
Input Price:Input: $2.50/1MOutput Price:Output: $10.00/1M
openai logo
OpenAI
Input Price:Input: $2.50/1MOutput Price:Output: $10.00/1M

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 GPT-4o and Step-3.5-Flash side-by-side, then vote on the output you prefer.

GPT-4o
✓ Preferred
Step-3.5-Flash
Open in Playground

FAQ

Common questions about GPT-4o vs Step-3.5-Flash.

Which is better, GPT-4o or Step-3.5-Flash?

Step-3.5-Flash leads the LLM Stats Score 37.3 to 11.7. GPT-4o is made by OpenAI 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 GPT-4o compare to Step-3.5-Flash in benchmarks?

GPT-4o scores MGSM: 90.5%, HumanEval: 90.2%, MMLU: 88.7%, DROP: 83.4%, MATH: 76.6%. 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 GPT-4o cheaper than Step-3.5-Flash?

Step-3.5-Flash is 25.0x cheaper for input tokens. GPT-4o costs $2.50/M input and $10.00/M output via azure. Step-3.5-Flash costs $0.10/M input and $0.40/M output via stepfun.

What are the context window sizes for GPT-4o and Step-3.5-Flash?

GPT-4o supports 128K 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 GPT-4o and Step-3.5-Flash?

Key differences include LLM Stats Score (11.7 vs 37.3), context window (128K vs 66K), input pricing ($2.50 vs $0.10/M), multimodal support (yes vs no), licensing (Proprietary vs Apache 2.0). See the full comparison above for benchmark-by-benchmark results.

Who makes GPT-4o and Step-3.5-Flash?

GPT-4o is developed by OpenAI and Step-3.5-Flash is developed by StepFun.

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