Noometry

Model comparison

Claude Opus 4.5 vs Gemini 2.5 Flash

Claude Opus 4.5 is the stronger model overall, scoring 50.5 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 4.5's lead doesn't matter for your workload.

Last verified . 41 shared benchmarks.

Claude Opus 4.5 Anthropic

50.5

Rank #47 Confirmed

Gemini 2.5 Flash Google

39.3

Rank #170 Confirmed

Summary

  • They share 41 benchmarks with published results for both. Claude Opus 4.5 scores higher in 7 categories and Gemini 2.5 Flash in 3 categories; 10 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Claude Opus 4.5 leads 42.6 to 18.1.
  • The biggest single-benchmark swing is SWE-bench Verified (bash only): 76.8% for Claude Opus 4.5 and 28.7% 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 4.5.
  • Gemini 2.5 Flash accepts more context: 1.05M tokens versus 200K.

Side by side

Claude Opus 4.5Gemini 2.5 Flash
ProviderAnthropicGoogle
Noometry Index50.539.3
Released2025-11-012025-04-17
WeightsProprietaryProprietary
Context window200K1.05M
Max output64K66K
Input $ / M tokens$5$0.30
Output $ / M tokens$25$2.50
Results tracked6954

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Category by category

Coding Claude Opus 4.5 leads

Claude Opus 4.5: 54.8 (#27), Gemini 2.5 Flash: 35.8 (#220)

BenchmarkClaude Opus 4.5Gemini 2.5 Flash
SWE-bench Verified (bash only)76.8%28.7%
WeirdML63.7%41.9%
LMArena Coding15041424
ALE-Bench1,025661.88
SWE-bench Verified76.7%—
Aider Polyglot—55.1%
LMArena WebDev1494—
SWE-bench Multilingual70.7%—
GSO26.5%—
AlgoTune1.77—

Agentic & Tool Use Claude Opus 4.5 leads

Claude Opus 4.5: 47.3 (#12), Gemini 2.5 Flash: 30.8 (#74)

BenchmarkClaude Opus 4.5Gemini 2.5 Flash
Terminal-Bench63.1%17.1%
Berkeley Function Calling Leaderboard77.5%56.2%
BALROG43.5%33.5%
Vending-Bench 24,967548.84
GDPval45.5%—
Remote Labor Index3.8%—
TheAgentCompany—41.1%
τ²-bench Airline84%—
τ²-bench Banking24.7%—
τ²-bench Retail79.6%—
τ²-bench Telecom92.3%—
Cybench82%—
DeepResearch Bench54.8%—
OSWorld66.3%—
LMArena Search1180—
METR Time Horizons75%—

Reasoning Claude Opus 4.5 leads

Claude Opus 4.5: 42.6 (#51), Gemini 2.5 Flash: 18.1 (#286)

BenchmarkClaude Opus 4.5Gemini 2.5 Flash
ARC-AGI-237.6%2.5%
SimpleBench62%41.2%
Kagi LLM Benchmark80.2%56.8%
ARC-AGI-180%33.3%
EnigmaEval11.9%2.7%
LMArena Hard Prompts14761422
DTBench89.9%76.5%
LMCA44.5%27.5%
Epoch Capabilities Index150.09143.03
ForecastBench60.760.6
NYT Connections (extended)52.5%—
CritPt—1.1%
Chess Puzzles12%—
EBR-Bench14.3%—
Mystery Game Puzzles22%—

Math Gemini 2.5 Flash leads

Claude Opus 4.5: 38.6 (#132), Gemini 2.5 Flash: 39.9 (#98)

BenchmarkClaude Opus 4.5Gemini 2.5 Flash
OTIS Mock AIME 2024-202586.1%73.1%
LMArena Math14631415
FrontierMath (Feb 2025 set)20.7%4.8%
FrontierMath Tier 4 (v1)4.2%4.2%
FrontierMath (Tiers 1-3)34.4%—
FrontierMath Tier 44.9%—
ProofBench36%—
Omni-MATH—38.5%

Knowledge Claude Opus 4.5 leads

Claude Opus 4.5: 56.5 (#44), Gemini 2.5 Flash: 36.4 (#168)

BenchmarkClaude Opus 4.5Gemini 2.5 Flash
Humanity's Last Exam25.2%12.1%
Vectara Hallucination Rate10.9%7.8%
LMArena Expert14871426
GPQA Diamond86%—
SimpleQA Verified45.7%—
MMLU-Pro—63.9%
Confabulations—16.8%
GPQA (HELM)—39%

Multimodal Gemini 2.5 Flash leads

Claude Opus 4.5: 31.4 (#107), Gemini 2.5 Flash: 41.8 (#32)

BenchmarkClaude Opus 4.5Gemini 2.5 Flash
GeoBench75%76%
VPCT40%46.2%
LMArena Vision—1253
Furniture Assembly28.3%—
LMArena Document1462—
SpatialViz-Bench—36.9%

Multilingual Claude Opus 4.5 leads

Claude Opus 4.5: 54.3 (#47), Gemini 2.5 Flash: 52.3 (#88)

BenchmarkClaude Opus 4.5Gemini 2.5 Flash
LMArena Non-English14381409
LMArena Chinese14701450
LMArena French14711433
LMArena German14491418
LMArena Japanese14161405
LMArena Korean14241385
LMArena Russian14471415
LMArena Spanish14581421

Instruction Following Claude Opus 4.5 leads

Claude Opus 4.5: 77.5 (#19), Gemini 2.5 Flash: 75.7 (#54)

BenchmarkClaude Opus 4.5Gemini 2.5 Flash
LMArena Instruction Following14781405
IFEval—89.8%

Long Context Gemini 2.5 Flash leads

Claude Opus 4.5: 46.5 (#22), Gemini 2.5 Flash: 47.5 (#17)

BenchmarkClaude Opus 4.5Gemini 2.5 Flash
LMArena Longer Query14801419
Fiction.LiveBench—77.8%
CL-bench21.1%—

Writing & Preference Claude Opus 4.5 leads

Claude Opus 4.5: 68.1 (#28), Gemini 2.5 Flash: 53.8 (#157)

BenchmarkClaude Opus 4.5Gemini 2.5 Flash
LMArena Text14511417
LMArena Creative Writing14451400
EQ-Bench Creative Writing16871137
LMArena Multi-Turn14661408
Short-Story Creative Writing—76.5%
WildBench—81.7%

Frequently asked questions

Is Claude Opus 4.5 better than Gemini 2.5 Flash?

Claude Opus 4.5 is the stronger model overall, scoring 50.5 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 4.5's lead doesn't matter for your workload.

Which is cheaper, Claude Opus 4.5 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 4.5 lists at $5 and $25.

Is Claude Opus 4.5 or Gemini 2.5 Flash better for coding?

Claude Opus 4.5 scores higher on coding benchmarks: 54.8 versus 35.8 in the Noometry coding category.

Which has the bigger context window?

Gemini 2.5 Flash does, with 1.05M tokens against 200K.

How many benchmarks do Claude Opus 4.5 and Gemini 2.5 Flash share?

41 benchmarks have published results for both models. Claude Opus 4.5 has 69 scored results on Noometry and Gemini 2.5 Flash has 54.

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