Model comparison

Claude Opus 5.5 vs Seed 2.0 Pro

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 43.2 on the Noometry Index. Seed 2.0 Pro costs 7.1× less per token, which makes it the better buy when Claude Opus 5.5's lead doesn't matter for your workload.

Last verified . 16 shared benchmarks.

Claude Opus 5.5 Anthropic

68.6

Rank #3 Confirmed

Seed 2.0 Pro ByteDance Seed

43.2

Rank #96 Confirmed

Summary

  • They share 16 benchmarks with published results for both. Claude Opus 5.5 scores higher in 9 categories and Seed 2.0 Pro in 0 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Claude Opus 5.5 leads 80.2 to 24.1.
  • The biggest single-benchmark swing is NYT Connections (extended): 88.5% for Claude Opus 5.5 and 28.4% for Seed 2.0 Pro.
  • Seed 2.0 Pro is cheaper at $0.50 / $3 per million input/output tokens, against $4 / $20 for Claude Opus 5.5.
  • Claude Opus 5.5 accepts more context: 1M tokens versus 256K.

Side by side

Claude Opus 5.5 and Seed 2.0 Pro specifications
Claude Opus 5.5Seed 2.0 Pro
ProviderAnthropicByteDance Seed
Noometry Index68.643.2
Released2026-09-222026-02-14
WeightsProprietaryProprietary
Context window1M256K
Max output128K128K
Input $ / M tokens$4$0.50
Output $ / M tokens$20$3
Results tracked4420

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Category by category

Coding Claude Opus 5.5 leads

Claude Opus 5.5: 71.9 (#3), Seed 2.0 Pro: 43.5 (#86)

Coding benchmarks
BenchmarkClaude Opus 5.5Seed 2.0 Pro
LMArena Coding15471472
FrontierCode54.6%—
CursorBench57.8%—
LMArena WebDev1813—
FrontierSWE62.3%—
SciCode66.9%—
MirrorCode77.4%—
ALE-Bench2,147—

Agentic & Tool Use Not comparable

Claude Opus 5.5: 45.3 (#15), Seed 2.0 Pro: —

Agentic & Tool Use benchmarks
BenchmarkClaude Opus 5.5Seed 2.0 Pro
APEX-Agents73.5%—
GDP.pdf30.6%—
Vending-Bench 29,235—

Reasoning Claude Opus 5.5 leads

Claude Opus 5.5: 80.2 (#3), Seed 2.0 Pro: 24.1 (#165)

Reasoning benchmarks
BenchmarkClaude Opus 5.5Seed 2.0 Pro
NYT Connections (extended)88.5%28.4%
LMArena Hard Prompts15351453
ARC-AGI-293.3%—
ARC-AGI-198.5%—
CritPt31.7%—
Thematic Generalization—57.1%
EBR-Bench71.4%—
Mystery Game Puzzles71%—
DTBench98.9%—
LMCA68.2%—
Epoch Capabilities Index167.33—

Math Claude Opus 5.5 leads

Claude Opus 5.5: 91.8 (#3), Seed 2.0 Pro: 39.3 (#108)

Math benchmarks
BenchmarkClaude Opus 5.5Seed 2.0 Pro
LMArena Math15061439
FrontierMath (Tiers 1-3)91.2%—
FrontierMath Tier 495%—
OTIS Mock AIME 2024-2025100%—
ProofBench100%—
FrontierMath Erdős2.9%—

Knowledge Claude Opus 5.5 leads

Claude Opus 5.5: 66.4 (#10), Seed 2.0 Pro: 40.2 (#122)

Knowledge benchmarks
BenchmarkClaude Opus 5.5Seed 2.0 Pro
LMArena Expert15471440
GPQA Diamond90.6%—
SimpleQA Verified72.2%—

Multimodal Claude Opus 5.5 leads

Claude Opus 5.5: 57.8 (#1), Seed 2.0 Pro: 41.5 (#35)

Multimodal benchmarks
BenchmarkClaude Opus 5.5Seed 2.0 Pro
LMArena Vision13211274
Blueprint-Bench 251.2%—
Furniture Assembly83.3%—

Multilingual Claude Opus 5.5 leads

Claude Opus 5.5: 59.1 (#2), Seed 2.0 Pro: 54.5 (#39)

Multilingual benchmarks
BenchmarkClaude Opus 5.5Seed 2.0 Pro
LMArena Non-English15071441
LMArena Chinese15881489
LMArena French15141471
LMArena Russian15201449
LMArena Spanish15071460
LMArena German—1442
LMArena Japanese—1408
LMArena Korean—1411

Instruction Following Claude Opus 5.5 leads

Claude Opus 5.5: 80.0 (#3), Seed 2.0 Pro: 74.5 (#91)

Instruction Following benchmarks
BenchmarkClaude Opus 5.5Seed 2.0 Pro
LMArena Instruction Following15371414

Long Context Claude Opus 5.5 leads

Claude Opus 5.5: 47.1 (#19), Seed 2.0 Pro: 43.6 (#90)

Long Context benchmarks
BenchmarkClaude Opus 5.5Seed 2.0 Pro
LMArena Longer Query15321428

Writing & Preference Claude Opus 5.5 leads

Claude Opus 5.5: 78.2 (#3), Seed 2.0 Pro: 62.9 (#69)

Writing & Preference benchmarks
BenchmarkClaude Opus 5.5Seed 2.0 Pro
LMArena Text15151448
LMArena Creative Writing15331406
LMArena Multi-Turn14991441
EQ-Bench Creative Writing2050—

Frequently asked questions

Is Claude Opus 5.5 better than Seed 2.0 Pro?

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 43.2 on the Noometry Index. Seed 2.0 Pro costs 7.1× less per token, which makes it the better buy when Claude Opus 5.5's lead doesn't matter for your workload.

Which is cheaper, Claude Opus 5.5 or Seed 2.0 Pro?

Seed 2.0 Pro is cheaper. It lists at $0.50 per million input tokens and $3 per million output tokens; Claude Opus 5.5 lists at $4 and $20.

Is Claude Opus 5.5 or Seed 2.0 Pro better for coding?

Claude Opus 5.5 scores higher on coding benchmarks: 71.9 versus 43.5 in the Noometry coding category.

Which has the bigger context window?

Claude Opus 5.5 does, with 1M tokens against 256K.

How many benchmarks do Claude Opus 5.5 and Seed 2.0 Pro share?

16 benchmarks have published results for both models. Claude Opus 5.5 has 44 scored results on Noometry and Seed 2.0 Pro has 20.

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