Noometry

Model comparison

Claude Opus 5.5 vs Inkling

Claude Opus 5.5 is the stronger model overall, scoring 68.5 to 44.1 on the Noometry Index. Inkling costs 3.1× less per token, which makes it the better buy when Claude Opus 5.5's lead doesn't matter for your workload.

Last verified . 28 shared benchmarks.

Claude Opus 5.5 Anthropic

68.5

Rank #3 Confirmed

Inkling Thinking Machines Lab

44.1

Rank #75 Confirmed

Summary

  • They share 28 benchmarks with published results for both. Claude Opus 5.5 scores higher in 9 categories and Inkling in 0 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in math, where Claude Opus 5.5 leads 92.4 to 31.2.
  • The biggest single-benchmark swing is ProofBench: 100% for Claude Opus 5.5 and 0% for Inkling.
  • Inkling is cheaper at $1.87 / $4.68 per million input/output tokens, against $4 / $20 for Claude Opus 5.5.
  • Claude Opus 5.5 accepts more context: 1M tokens versus 66K.
  • Inkling has downloadable open weights; the other is API-only.

Side by side

Claude Opus 5.5Inkling
ProviderAnthropicThinking Machines Lab
Noometry Index68.544.1
Released2026-09-222026-07-15
WeightsProprietaryOpen
Context window1M66K
Max output128K66K
Input $ / M tokens$4$1.87
Output $ / M tokens$20$4.68
Results tracked3541

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Category by category

Coding Claude Opus 5.5 leads

Claude Opus 5.5: 71.4 (#1), Inkling: 34.1 (#229)

BenchmarkClaude Opus 5.5Inkling
FrontierCode54.4%14%
LMArena WebDev18201412
FrontierSWE62.3%4.1%
SciCode66.9%47%
LMArena Coding15451463
CursorBench57.8%—
WeirdML—32.3%
MirrorCode77.4%—
ALE-Bench—946

Agentic & Tool Use Claude Opus 5.5 leads

Claude Opus 5.5: 45.3 (#13), Inkling: 29.5 (#76)

BenchmarkClaude Opus 5.5Inkling
APEX-Agents73.5%33.8%
τ²-bench Banking—25%
GDP.pdf30.6%—

Reasoning Claude Opus 5.5 leads

Claude Opus 5.5: 79.5 (#2), Inkling: 40.6 (#48)

BenchmarkClaude Opus 5.5Inkling
ARC-AGI-292.5%36.5%
ARC-AGI-197.5%79.5%
CritPt31.7%5.4%
LMArena Hard Prompts15451452
DTBench98.9%87.5%
LMCA68.2%37.6%
SimpleBench—50%
NYT Connections (extended)88.5%—
Chess Puzzles—21%
EBR-Bench71.4%—
Mystery Game Puzzles71%—
Epoch Capabilities Index—148.6

Math Claude Opus 5.5 leads

Claude Opus 5.5: 92.4 (#2), Inkling: 31.2 (#198)

BenchmarkClaude Opus 5.5Inkling
FrontierMath (Tiers 1-3)91.2%33.3%
FrontierMath Tier 495%4.9%
OTIS Mock AIME 2024-2025100%88.9%
ProofBench100%0%
LMArena Math—1482

Knowledge Claude Opus 5.5 leads

Claude Opus 5.5: 66.6 (#9), Inkling: 55.2 (#44)

BenchmarkClaude Opus 5.5Inkling
GPQA Diamond90.6%88.3%
SimpleQA Verified72.2%40.3%
LMArena Expert15641468

Multimodal Not comparable

Claude Opus 5.5: 56.5 (#2), Inkling: —

BenchmarkClaude Opus 5.5Inkling
Furniture Assembly83.3%—

Multilingual Claude Opus 5.5 leads

Claude Opus 5.5: 59.8 (#1), Inkling: 54.2 (#49)

BenchmarkClaude Opus 5.5Inkling
LMArena Non-English15131434
LMArena Chinese15721495
LMArena Russian15321430
LMArena French—1453
LMArena German—1456
LMArena Japanese—1428
LMArena Korean—1401
LMArena Spanish—1442

Instruction Following Claude Opus 5.5 leads

Claude Opus 5.5: 80.1 (#2), Inkling: 75.3 (#65)

BenchmarkClaude Opus 5.5Inkling
LMArena Instruction Following15351427

Long Context Claude Opus 5.5 leads

Claude Opus 5.5: 47.3 (#18), Inkling: 43.9 (#79)

BenchmarkClaude Opus 5.5Inkling
LMArena Longer Query15401436

Writing & Preference Claude Opus 5.5 leads

Claude Opus 5.5: 78.7 (#3), Inkling: 65.5 (#48)

BenchmarkClaude Opus 5.5Inkling
LMArena Text15181443
LMArena Creative Writing15381390
EQ-Bench Creative Writing20501611
LMArena Multi-Turn15201436
EQ-Bench 4—1226

Frequently asked questions

Is Claude Opus 5.5 better than Inkling?

Claude Opus 5.5 is the stronger model overall, scoring 68.5 to 44.1 on the Noometry Index. Inkling costs 3.1× 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 Inkling?

Inkling is cheaper. It lists at $1.87 per million input tokens and $4.68 per million output tokens; Claude Opus 5.5 lists at $4 and $20.

Is Claude Opus 5.5 or Inkling better for coding?

Claude Opus 5.5 scores higher on coding benchmarks: 71.4 versus 34.1 in the Noometry coding category.

Which has the bigger context window?

Claude Opus 5.5 does, with 1M tokens against 66K.

How many benchmarks do Claude Opus 5.5 and Inkling share?

28 benchmarks have published results for both models. Claude Opus 5.5 has 35 scored results on Noometry and Inkling has 41.

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