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GPT-5.6 Sol vs Seed 2.1 Pro

GPT-5.6 Sol leads the LLM Stats Score 57.2 to 47.0.

OpenAI · ByteDance · Updated for 2026

Which is better?

GPT-5.6 Sol leads the overall LLM Stats Score 57.2 to 47.0, ranking #1 overall.

In the 7 individual benchmarks reported for both models, GPT-5.6 Sol wins 7; this is a narrower head-to-head signal than the composite indexes.

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

Choose GPT-5.6 Sol

  • overall performance matters — it scores 57.2 and ranks #1 on LLM Stats
  • your work emphasizes reasoning and coding — it leads those capability indexes
  • you value its reported benchmark strengths — it wins 7 of 7 exact shared results
  • you want the most recent training data — it shipped Jul 2026

Choose Seed 2.1 Pro

  • you are already invested in the ByteDance ecosystem

At a glance

The differences that matter most.

GPT-5.6 Sol
OpenAI
Seed 2.1 Pro
ByteDance
Core performance indexes
LLM Stats Score
57.2
#1
47.0
#20
Reasoning
56.6
#2
47.9
#18
Coding
50.6
#1
36.0
#25
Agents
44.3
#1
33.1
#22
Cost, coverage & limits
Benchmark wins
7 of 7
0 of 7
Input price
$5.00 / M
— / M
Output price
$30.00 / M
— / M
Context window
1,050,000
—

Capability indexes

Additional strengths measured across groups of related public benchmarks

6 shared
Index
GPT-5.6 Sol
Seed 2.1 Pro
Math
36.5#35
39.8#15
Vision
38.2#5
34.9#10
Tool use
34.3#3
27.9#17
Long context
32.4#2
30.5#4
Multimodal
38.3#3
37.7#5
1 more shared indexes
Finance
16.5#105
33.9#7
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

44 reported for GPT-5.6 Sol · 94 for Seed 2.1 Pro

7 shared

GPT-5.6 Sol outperforms in 7 benchmarks (Agents' Last Exam, BrowseComp, DeepSWE, MMMU-Pro, SWE-Bench Pro, Terminal-Bench 2.1, Toolathlon), while Seed 2.1 Pro is better at 0 benchmarks.

GPT-5.6 Sol significantly outperforms across most benchmarks.

Fri Aug 28 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Context Window

Maximum input and output token capacity

Only GPT-5.6 Sol specifies input context (1,050,000 tokens). Only GPT-5.6 Sol specifies output context (128,000 tokens).

OpenAI
GPT-5.6 Sol
Input1,050,000 tokens
Output128,000 tokens
ByteDance
Seed 2.1 Pro
Input- tokens
Output- tokens
Fri Aug 28 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both GPT-5.6 Sol and Seed 2.1 Pro support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

GPT-5.6 Sol

Text
Images
Audio
Video

Seed 2.1 Pro

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

GPT-5.6 Sol

Proprietary

Closed source

Seed 2.1 Pro

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-5.6 Sol was released on 2026-07-09, while Seed 2.1 Pro was released on 2026-06-24.

GPT-5.6 Sol is 1 month newer than Seed 2.1 Pro.

GPT-5.6 Sol

Jul 9, 2026

1 months ago

2w newer
Seed 2.1 Pro

Jun 24, 2026

2 months ago

Knowledge Cutoff

When training data ends

GPT-5.6 Sol has a documented knowledge cutoff of 2026-02-16, while Seed 2.1 Pro's cutoff date is not specified.

We can confirm GPT-5.6 Sol's training data extends to 2026-02-16, but cannot make a direct comparison without Seed 2.1 Pro's cutoff date.

GPT-5.6 Sol

Feb 2026

Seed 2.1 Pro

—

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against GPT-5.6 Sol and Seed 2.1 Pro side-by-side, then vote on the output you prefer.

GPT-5.6 Sol
✓ Preferred
Seed 2.1 Pro
Open in Playground

FAQ

Common questions about GPT-5.6 Sol vs Seed 2.1 Pro.

Which is better, GPT-5.6 Sol or Seed 2.1 Pro?

GPT-5.6 Sol leads the LLM Stats Score 57.2 to 47.0. GPT-5.6 Sol is made by OpenAI and Seed 2.1 Pro is made by ByteDance. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does GPT-5.6 Sol compare to Seed 2.1 Pro in benchmarks?

GPT-5.6 Sol scores Connectors: 100.0%, Capture-the-Flag Challenges (Internal): 96.7%, HealthBench Consensus: 95.5%, GPQA: 94.6%, MRCR v2 (8-needle): 91.5%. Seed 2.1 Pro scores CharXiv-D: 95.5%, MathVision: 94.5%, MathVista: 90.7%, MathVerse: 89.7%, Video-MME: 89.2%.

What are the context window sizes for GPT-5.6 Sol and Seed 2.1 Pro?

GPT-5.6 Sol supports 1.1M tokens and Seed 2.1 Pro supports an unknown number of tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between GPT-5.6 Sol and Seed 2.1 Pro?

Key differences include LLM Stats Score (57.2 vs 47.0). See the full comparison above for benchmark-by-benchmark results.

Who makes GPT-5.6 Sol and Seed 2.1 Pro?

GPT-5.6 Sol is developed by OpenAI and Seed 2.1 Pro is developed by ByteDance.

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