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Claude Sonnet 5 vs Seed 2.1 Pro

Claude Sonnet 5 and Seed 2.1 Pro are closely matched at 48.5 and 46.4 on the LLM Stats Score.

Anthropic · ByteDance · Updated for 2026

Which is better?

Claude Sonnet 5 and Seed 2.1 Pro are closely matched on the overall LLM Stats Score at 48.5 and 46.4.

In the 6 individual benchmarks reported for both models, Claude Sonnet 5 wins 4; 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 Claude Sonnet 5

  • you value its reported benchmark strengths — it wins 4 of 6 exact shared results
  • you want the most recent training data — it shipped Jun 2026

Choose Seed 2.1 Pro

  • you are already invested in the ByteDance ecosystem

At a glance

The differences that matter most.

Claude Sonnet 5
Anthropic
Seed 2.1 Pro
ByteDance
Core performance indexes
LLM Stats Score
48.5
#21
46.4
#25
Reasoning
47.8
#20
47.2
#22
Coding
37.0
#17
33.7
#31
Agents
31.4
#24
31.3
#26
Cost, coverage & limits
Benchmark wins
4 of 6
2 of 6
Input price
$2.00 / M
— / M
Output price
$10.00 / M
— / M
Context window
1,000,000
—

Capability indexes

Additional strengths measured across groups of related public benchmarks

4 shared
Index
Claude Sonnet 5
Seed 2.1 Pro
Math
38.4#26
39.1#20
Vision
33.7#16
34.2#12
Tool use
23.9#37
26.4#27
Multimodal
32.3#20
37.4#4
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

23 reported for Claude Sonnet 5 · 94 for Seed 2.1 Pro

6 shared

Claude Sonnet 5 outperforms in 4 benchmarks (CharXiv-R, Humanity's Last Exam, SWE-Bench Pro, Toolathlon), while Seed 2.1 Pro is better at 2 benchmarks (BrowseComp, OfficeQA Pro).

Claude Sonnet 5 shows notably better performance in the majority of benchmarks.

Sat Sep 05 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Context Window

Maximum input and output token capacity

Only Claude Sonnet 5 specifies input context (1,000,000 tokens). Only Claude Sonnet 5 specifies output context (64,000 tokens).

Anthropic
Claude Sonnet 5
Input1,000,000 tokens
Output64,000 tokens
ByteDance
Seed 2.1 Pro
Input- tokens
Output- tokens
Sat Sep 05 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Claude Sonnet 5 and Seed 2.1 Pro support multimodal inputs.

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

Claude Sonnet 5

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.

Claude Sonnet 5

Proprietary

Closed source

Seed 2.1 Pro

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Sonnet 5 was released on 2026-06-30, while Seed 2.1 Pro was released on 2026-06-24.

Claude Sonnet 5 is 0 month newer than Seed 2.1 Pro.

Claude Sonnet 5

Jun 30, 2026

2 months ago

6d newer
Seed 2.1 Pro

Jun 24, 2026

2 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

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against Claude Sonnet 5 and Seed 2.1 Pro side-by-side, then vote on the output you prefer.

Claude Sonnet 5
✓ Preferred
Seed 2.1 Pro
Open in Playground

FAQ

Common questions about Claude Sonnet 5 vs Seed 2.1 Pro.

Which is better, Claude Sonnet 5 or Seed 2.1 Pro?

Claude Sonnet 5 and Seed 2.1 Pro are closely matched on the LLM Stats Score at 48.5 and 46.4. Claude Sonnet 5 is made by Anthropic 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 Claude Sonnet 5 compare to Seed 2.1 Pro in benchmarks?

Claude Sonnet 5 scores CharXiv-R: 88.3%, ChartMuseum: 86.7%, SWE-Bench Verified: 85.2%, BrowseComp: 84.7%, GDP.pdf: 81.6%. 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 Claude Sonnet 5 and Seed 2.1 Pro?

Claude Sonnet 5 supports 1.0M 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 Claude Sonnet 5 and Seed 2.1 Pro?

Key differences include LLM Stats Score (48.5 vs 46.4). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Sonnet 5 and Seed 2.1 Pro?

Claude Sonnet 5 is developed by Anthropic and Seed 2.1 Pro is developed by ByteDance.

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