Model Comparison

Kimi K3 vs Seed 2.1 ProWhich is better in 2026?

Kimi K3 significantly outperforms across most benchmarks.

Verdict: Kimi K3 vs Seed 2.1 Pro — which is better?

Kimi K3 (by Moonshot AI) and Seed 2.1 Pro (by ByteDance) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

Kimi K3 outperforms in 13 benchmarks (APEX-Agents, BabyVision, BrowseComp, CharXiv-R, DeepSWE, Humanity's Last Exam, MathVision, MCP Atlas, PostTrainBench, Program Bench, Terminal-Bench 2.1, Toolathlon, ZEROBench), while Seed 2.1 Pro is better at 3 benchmarks (MMMU-Pro, OfficeQA Pro, WorldVQA). Kimi K3 significantly outperforms across most benchmarks.

Choose Kimi K3 if…

  • you want the strongest raw capability — it leads on 13 of 16 shared benchmarks
  • you want the most recent training data — it shipped Jul 2026

Choose Seed 2.1 Pro if…

  • you are already invested in the ByteDance ecosystem

Performance Benchmarks

Comparative analysis across standard metrics

16 benchmarks

Kimi K3 outperforms in 13 benchmarks (APEX-Agents, BabyVision, BrowseComp, CharXiv-R, DeepSWE, Humanity's Last Exam, MathVision, MCP Atlas, PostTrainBench, Program Bench, Terminal-Bench 2.1, Toolathlon, ZEROBench), while Seed 2.1 Pro is better at 3 benchmarks (MMMU-Pro, OfficeQA Pro, WorldVQA).

Kimi K3 significantly outperforms across most benchmarks.

Sun Jul 26 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only Kimi K3 specifies input context (1,048,576 tokens). Only Kimi K3 specifies output context (1,048,576 tokens).

Moonshot AI
Kimi K3
Input1,048,576 tokens
Output1,048,576 tokens
ByteDance
Seed 2.1 Pro
Input- tokens
Output- tokens
Sun Jul 26 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Kimi K3 and Seed 2.1 Pro support multimodal inputs.

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

Kimi K3

Text
Images
Audio
Video

Seed 2.1 Pro

Text
Images
Audio
Video

Release Timeline

When each model was launched

Kimi K3 was released on 2026-07-16, while Seed 2.1 Pro was released on 2026-06-24.

Kimi K3 is 1 month newer than Seed 2.1 Pro.

Kimi K3

Jul 16, 2026

1 weeks ago

3w newer
Seed 2.1 Pro

Jun 24, 2026

1 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→

Key Takeaways

Moonshot AI
Larger context window (1,048,576 tokens)
Has open weights
Higher APEX-Agents score (37.6% vs 33.8%)
Higher BabyVision score (85.7% vs 73.7%)
Higher BrowseComp score (91.2% vs 86.2%)
Higher CharXiv-R score (91.3% vs 86.4%)
Higher DeepSWE score (67.5% vs 32.7%)
Higher Humanity's Last Exam score (56.0% vs 55.7%)
Higher MathVision score (97.8% vs 94.5%)
Higher MCP Atlas score (84.2% vs 83.8%)
Higher PostTrainBench score (36.6% vs 16.5%)
Higher Program Bench score (77.8% vs 50.3%)
Higher Terminal-Bench 2.1 score (88.3% vs 71.0%)
Higher Toolathlon score (73.2% vs 50.6%)
Higher ZEROBench score (41.0% vs 18.0%)
ByteDance
Higher MMMU-Pro score (82.7% vs 81.6%)
Higher OfficeQA Pro score (72.2% vs 63.3%)
Higher WorldVQA score (53.0% vs 51.0%)

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Kimi K3 and Seed 2.1 Pro side-by-side, then vote on the output you prefer.

Kimi K3
✓ Preferred
Seed 2.1 Pro
Open in Playground
AI Model Comparison Table
Feature
Moonshot AI
Kimi K3
ByteDance
Seed 2.1 Pro

FAQ

Common questions about Kimi K3 vs Seed 2.1 Pro.

Which is better, Kimi K3 or Seed 2.1 Pro?

Kimi K3 significantly outperforms across most benchmarks. Kimi K3 is made by Moonshot AI and Seed 2.1 Pro is made by ByteDance. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Kimi K3 compare to Seed 2.1 Pro in benchmarks?

Kimi K3 scores MathVision: 97.8%, DeepSearchQA: 95.0%, GPQA: 93.5%, CharXiv-R: 91.3%, BrowseComp: 91.2%. 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 Kimi K3 and Seed 2.1 Pro?

Kimi K3 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 Kimi K3 and Seed 2.1 Pro?

Key differences include licensing (Unknown vs Proprietary). See the full comparison above for benchmark-by-benchmark results.

Who makes Kimi K3 and Seed 2.1 Pro?

Kimi K3 is developed by Moonshot AI and Seed 2.1 Pro is developed by ByteDance.

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