Noometry

Model comparison

Claude Opus 5.5 vs Mercury

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 37.6 on the Noometry Index.

Last verified . 8 shared benchmarks.

Claude Opus 5.5 Anthropic

68.6

Rank #3 Confirmed

Mercury Inception

37.6

Rank #199 Confirmed

Summary

  • They share 8 benchmarks with published results for both. Claude Opus 5.5 scores higher in 6 categories and Mercury in 0 categories; 6 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Claude Opus 5.5 leads 80.2 to 17.5.

Side by side

Claude Opus 5.5Mercury
ProviderAnthropicInception
Noometry Index68.637.6
Released2026-09-22—
WeightsProprietaryProprietary
Context window1M—
Max output128K—
Input $ / M tokens$4—
Output $ / M tokens$20—
Results tracked449

Sponsored placements are available on pages like this one. Advertise on Noometry

Category by category

Coding Claude Opus 5.5 leads

Claude Opus 5.5: 71.9 (#3), Mercury: 38.7 (#170)

BenchmarkClaude Opus 5.5Mercury
LMArena Coding15471322
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), Mercury: —

BenchmarkClaude Opus 5.5Mercury
APEX-Agents73.5%—
GDP.pdf30.6%—
Vending-Bench 29,235—

Reasoning Claude Opus 5.5 leads

Claude Opus 5.5: 80.2 (#3), Mercury: 17.5 (#293)

BenchmarkClaude Opus 5.5Mercury
LMArena Hard Prompts15351285
ARC-AGI-293.3%—
Kagi LLM Benchmark—21.6%
NYT Connections (extended)88.5%—
ARC-AGI-198.5%—
CritPt31.7%—
EBR-Bench71.4%—
Mystery Game Puzzles71%—
DTBench98.9%—
LMCA68.2%—
Epoch Capabilities Index167.33—

Math Not comparable

Claude Opus 5.5: 91.8 (#3), Mercury: —

BenchmarkClaude Opus 5.5Mercury
FrontierMath (Tiers 1-3)91.2%—
FrontierMath Tier 495%—
OTIS Mock AIME 2024-2025100%—
ProofBench100%—
LMArena Math1506—
FrontierMath Erdős2.9%—

Knowledge Not comparable

Claude Opus 5.5: 66.4 (#10), Mercury: —

BenchmarkClaude Opus 5.5Mercury
GPQA Diamond90.6%—
SimpleQA Verified72.2%—
LMArena Expert1547—

Multimodal Not comparable

Claude Opus 5.5: 57.8 (#1), Mercury: —

BenchmarkClaude Opus 5.5Mercury
LMArena Vision1321—
Blueprint-Bench 251.2%—
Furniture Assembly83.3%—

Multilingual Claude Opus 5.5 leads

Claude Opus 5.5: 59.1 (#2), Mercury: 41.6 (#206)

BenchmarkClaude Opus 5.5Mercury
LMArena Non-English15071260
LMArena Chinese1588—
LMArena French1514—
LMArena Russian1520—
LMArena Spanish1507—

Instruction Following Claude Opus 5.5 leads

Claude Opus 5.5: 80.0 (#3), Mercury: 65.2 (#224)

BenchmarkClaude Opus 5.5Mercury
LMArena Instruction Following15371239

Long Context Claude Opus 5.5 leads

Claude Opus 5.5: 47.1 (#19), Mercury: 38.4 (#198)

BenchmarkClaude Opus 5.5Mercury
LMArena Longer Query15321266

Writing & Preference Claude Opus 5.5 leads

Claude Opus 5.5: 78.2 (#3), Mercury: 46.2 (#221)

BenchmarkClaude Opus 5.5Mercury
LMArena Text15151282
LMArena Creative Writing15331191
LMArena Multi-Turn14991282
EQ-Bench Creative Writing2050—

Frequently asked questions

Is Claude Opus 5.5 better than Mercury?

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 37.6 on the Noometry Index.

Is Claude Opus 5.5 or Mercury better for coding?

Claude Opus 5.5 scores higher on coding benchmarks: 71.9 versus 38.7 in the Noometry coding category.

How many benchmarks do Claude Opus 5.5 and Mercury share?

8 benchmarks have published results for both models. Claude Opus 5.5 has 44 scored results on Noometry and Mercury has 9.

Related comparisons

Go deeper