Noometry

Model comparison

Claude Opus 5 vs Gemini 2.5 Flash

Claude Opus 5 is the stronger model overall, scoring 67.8 to 39.3 on the Noometry Index. Gemini 2.5 Flash costs 12× less per token, which makes it the better buy when Claude Opus 5's lead doesn't matter for your workload.

Last verified . 31 shared benchmarks.

Claude Opus 5 Anthropic

67.8

Rank #4 Confirmed

Gemini 2.5 Flash Google

39.3

Rank #170 Confirmed

Summary

  • They share 31 benchmarks with published results for both. Claude Opus 5 scores higher in 9 categories and Gemini 2.5 Flash in 1 category; 10 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Claude Opus 5 leads 77.2 to 18.1.
  • The biggest single-benchmark swing is ARC-AGI-2: 90.4% for Claude Opus 5 and 2.5% for Gemini 2.5 Flash.
  • Gemini 2.5 Flash is cheaper at $0.30 / $2.50 per million input/output tokens, against $5 / $25 for Claude Opus 5.
  • Gemini 2.5 Flash accepts more context: 1.05M tokens versus 1M.

Side by side

Claude Opus 5Gemini 2.5 Flash
ProviderAnthropicGoogle
Noometry Index67.839.3
Released2026-07-242025-04-17
WeightsProprietaryProprietary
Context window1M1.05M
Max output128K66K
Input $ / M tokens$5$0.30
Output $ / M tokens$25$2.50
Results tracked5754

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Category by category

Coding Claude Opus 5 leads

Claude Opus 5: 67.5 (#5), Gemini 2.5 Flash: 35.8 (#220)

BenchmarkClaude Opus 5Gemini 2.5 Flash
WeirdML91.8%41.9%
LMArena Coding15341424
ALE-Bench2,165661.88
DeepSWE73.6%—
FrontierCode53.4%—
SWE-bench Verified (bash only)—28.7%
Aider Polyglot—55.1%
CursorBench46.6%—
LMArena WebDev1691—
FrontierSWE52%—
SciCode56.4%—

Agentic & Tool Use Claude Opus 5 leads

Claude Opus 5: 55.6 (#1), Gemini 2.5 Flash: 30.8 (#74)

BenchmarkClaude Opus 5Gemini 2.5 Flash
BALROG63.4%33.5%
Vending-Bench 211,182548.84
Terminal-Bench—17.1%
APEX-Agents65.8%—
Berkeley Function Calling Leaderboard—56.2%
OSWorld 2.031.4%—
TheAgentCompany—41.1%
τ²-bench Banking48.7%—
PostTrainBench35%—
GBAEval79.6%—
GDP.pdf24%—

Reasoning Claude Opus 5 leads

Claude Opus 5: 77.2 (#4), Gemini 2.5 Flash: 18.1 (#286)

BenchmarkClaude Opus 5Gemini 2.5 Flash
ARC-AGI-290.4%2.5%
SimpleBench80.6%41.2%
ARC-AGI-197.5%33.3%
CritPt29.1%1.1%
LMArena Hard Prompts15261422
DTBench97.9%76.5%
LMCA64.5%27.5%
Epoch Capabilities Index162.78143.03
Kagi LLM Benchmark—56.8%
NYT Connections (extended)94.3%—
Chess Puzzles42%—
EnigmaEval—2.7%
EBR-Bench45.7%—
Mystery Game Puzzles59%—
Bench to the Future 30.12—
ForecastBench—60.6

Math Claude Opus 5 leads

Claude Opus 5: 86.2 (#8), Gemini 2.5 Flash: 39.9 (#98)

BenchmarkClaude Opus 5Gemini 2.5 Flash
OTIS Mock AIME 2024-202598.9%73.1%
LMArena Math15311415
FrontierMath (Tiers 1-3)85.6%—
FrontierMath Tier 473.2%—
ProofBench99%—
Omni-MATH—38.5%
FrontierMath (Feb 2025 set)—4.8%
FrontierMath Tier 4 (v1)—4.2%

Knowledge Claude Opus 5 leads

Claude Opus 5: 66.8 (#9), Gemini 2.5 Flash: 36.4 (#168)

BenchmarkClaude Opus 5Gemini 2.5 Flash
LMArena Expert15571426
GPQA Diamond93.9%—
Humanity's Last Exam—12.1%
SimpleQA Verified59.9%—
MMLU-Pro—63.9%
Confabulations—16.8%
Vectara Hallucination Rate—7.8%
GPQA (HELM)—39%

Multimodal Claude Opus 5 leads

Claude Opus 5: 50.8 (#8), Gemini 2.5 Flash: 41.8 (#32)

BenchmarkClaude Opus 5Gemini 2.5 Flash
LMArena Vision13191253
GeoBench—76%
VPCT—46.2%
Blueprint-Bench 230.4%—
Furniture Assembly60.8%—
LMArena Document1516—
SpatialViz-Bench—36.9%

Multilingual Claude Opus 5 leads

Claude Opus 5: 58.8 (#4), Gemini 2.5 Flash: 52.3 (#88)

BenchmarkClaude Opus 5Gemini 2.5 Flash
LMArena Non-English15011409
LMArena Chinese15741450
LMArena French15191433
LMArena German15241418
LMArena Japanese15161405
LMArena Korean15211385
LMArena Russian15071415
LMArena Spanish15191421

Instruction Following Claude Opus 5 leads

Claude Opus 5: 79.2 (#7), Gemini 2.5 Flash: 75.7 (#54)

BenchmarkClaude Opus 5Gemini 2.5 Flash
LMArena Instruction Following15171405
IFEval—89.8%

Long Context Gemini 2.5 Flash leads

Claude Opus 5: 46.5 (#21), Gemini 2.5 Flash: 47.5 (#17)

BenchmarkClaude Opus 5Gemini 2.5 Flash
LMArena Longer Query15151419
Fiction.LiveBench—77.8%

Writing & Preference Claude Opus 5 leads

Claude Opus 5: 79.2 (#1), Gemini 2.5 Flash: 53.8 (#157)

BenchmarkClaude Opus 5Gemini 2.5 Flash
LMArena Text15071417
LMArena Creative Writing14911400
EQ-Bench Creative Writing21331137
LMArena Multi-Turn14991408
Short-Story Creative Writing—76.5%
WildBench—81.7%
EQ-Bench 41385—

Frequently asked questions

Is Claude Opus 5 better than Gemini 2.5 Flash?

Claude Opus 5 is the stronger model overall, scoring 67.8 to 39.3 on the Noometry Index. Gemini 2.5 Flash costs 12× less per token, which makes it the better buy when Claude Opus 5's lead doesn't matter for your workload.

Which is cheaper, Claude Opus 5 or Gemini 2.5 Flash?

Gemini 2.5 Flash is cheaper. It lists at $0.30 per million input tokens and $2.50 per million output tokens; Claude Opus 5 lists at $5 and $25.

Is Claude Opus 5 or Gemini 2.5 Flash better for coding?

Claude Opus 5 scores higher on coding benchmarks: 67.5 versus 35.8 in the Noometry coding category.

Which has the bigger context window?

Gemini 2.5 Flash does, with 1.05M tokens against 1M.

How many benchmarks do Claude Opus 5 and Gemini 2.5 Flash share?

31 benchmarks have published results for both models. Claude Opus 5 has 57 scored results on Noometry and Gemini 2.5 Flash has 54.

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