Model Comparison

Seed 2.1 Pro vs Kimi K3Which is better in 2026?

Kimi K3 shows notably better performance in the majority of benchmarks.

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

Seed 2.1 Pro (by ByteDance) and Kimi K3 (by Moonshot AI) 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.

Seed 2.1 Pro outperforms in 4 benchmarks (MMMU-Pro, OfficeQA Pro, WorldVQA, ZEROBench), while Kimi K3 is better at 12 benchmarks (APEX-Agents, BabyVision, BrowseComp, CharXiv-R, DeepSWE, Humanity's Last Exam, MathVision, MCP Atlas, PostTrainBench, Program Bench, Terminal-Bench 2.1, Toolathlon). Kimi K3 shows notably better performance in the majority of benchmarks.

Choose Seed 2.1 Pro if…

  • you are already invested in the ByteDance ecosystem

Choose Kimi K3 if…

  • you want the strongest raw capability — it leads on 12 of 16 shared benchmarks
  • you want the most recent training data — it shipped Jul 2026

Performance Benchmarks

Comparative analysis across standard metrics

16 benchmarks

Seed 2.1 Pro outperforms in 4 benchmarks (MMMU-Pro, OfficeQA Pro, WorldVQA, ZEROBench), while Kimi K3 is better at 12 benchmarks (APEX-Agents, BabyVision, BrowseComp, CharXiv-R, DeepSWE, Humanity's Last Exam, MathVision, MCP Atlas, PostTrainBench, Program Bench, Terminal-Bench 2.1, Toolathlon).

Kimi K3 shows notably better performance in the majority of benchmarks.

Fri Jul 17 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).

ByteDance
Seed 2.1 Pro
Input- tokens
Output- tokens
Moonshot AI
Kimi K3
Input1,048,576 tokens
Output1,048,576 tokens
Fri Jul 17 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Seed 2.1 Pro and Kimi K3 support multimodal inputs.

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

Seed 2.1 Pro

Text
Images
Audio
Video

Kimi K3

Text
Images
Audio
Video

Release Timeline

When each model was launched

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

Kimi K3 is 1 month newer than Seed 2.1 Pro.

Seed 2.1 Pro

Jun 24, 2026

3 weeks ago

Kimi K3

Jul 16, 2026

1 days ago

3w 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

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

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%)
Higher ZEROBench score (56.3% vs 41.0%)
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%)

Detailed Comparison

Interactive Arena

Judge for yourself.

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

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

FAQ

Common questions about Seed 2.1 Pro vs Kimi K3.

Which is better, Seed 2.1 Pro or Kimi K3?

Kimi K3 shows notably better performance in the majority of benchmarks. Seed 2.1 Pro is made by ByteDance and Kimi K3 is made by Moonshot AI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

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

Seed 2.1 Pro scores CharXiv-D: 95.5%, MathVision: 94.5%, MathVista: 90.7%, MathVerse: 89.7%, Video-MME: 89.2%. Kimi K3 scores MathVision: 97.8%, DeepSearchQA: 95.0%, GPQA: 93.5%, CharXiv-R: 91.3%, BrowseComp: 91.2%.

What are the context window sizes for Seed 2.1 Pro and Kimi K3?

Seed 2.1 Pro supports an unknown number of tokens and Kimi K3 supports 1.0M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Seed 2.1 Pro and Kimi K3?

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

Who makes Seed 2.1 Pro and Kimi K3?

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

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