Model comparison

Claude Opus 5.5 vs Inkling-Small

Claude Opus 5.5 is the stronger model overall, scoring 68.5 to 46.5 on the Noometry Index. Inkling-Small costs 13× less per token, which makes it the better buy when Claude Opus 5.5's lead doesn't matter for your workload.

Last verified . 24 shared benchmarks.

Claude Opus 5.5 Anthropic

68.5

Rank #3 Confirmed

Inkling-Small Thinking Machines Lab

46.5

Rank #57 Confirmed

Summary

  • They share 24 benchmarks with published results for both. Claude Opus 5.5 scores higher in 9 categories and Inkling-Small 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 44.9.
  • The biggest single-benchmark swing is ProofBench: 100% for Claude Opus 5.5 and 6% for Inkling-Small.
  • Inkling-Small is cheaper at $0.45 / $1.20 per million input/output tokens, against $4 / $20 for Claude Opus 5.5.
  • Claude Opus 5.5 accepts more context: 1M tokens versus 524K.
  • Inkling-Small has downloadable open weights; the other is API-only.

Side by side

Claude Opus 5.5 and Inkling-Small specifications
Claude Opus 5.5Inkling-Small
ProviderAnthropicThinking Machines Lab
Noometry Index68.546.5
Released2026-09-222026-07-15
WeightsProprietaryOpen
Context window1M524K
Max output128K1.05M
Input $ / M tokens$4$0.45
Output $ / M tokens$20$1.20
Results tracked3533

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Category by category

Coding Claude Opus 5.5 leads

Claude Opus 5.5: 71.4 (#1), Inkling-Small: 43.3 (#80)

Coding benchmarks
BenchmarkClaude Opus 5.5Inkling-Small
LMArena WebDev18201408
SciCode66.9%48.7%
LMArena Coding15451451
FrontierCode54.4%—
CursorBench57.8%—
FrontierSWE62.3%—
MirrorCode77.4%—

Agentic & Tool Use Not comparable

Claude Opus 5.5: 45.3 (#13), Inkling-Small: —

Agentic & Tool Use benchmarks
BenchmarkClaude Opus 5.5Inkling-Small
APEX-Agents73.5%—
GDP.pdf30.6%—

Reasoning Claude Opus 5.5 leads

Claude Opus 5.5: 79.5 (#2), Inkling-Small: 39.0 (#53)

Reasoning benchmarks
BenchmarkClaude Opus 5.5Inkling-Small
ARC-AGI-292.5%40.1%
ARC-AGI-197.5%84%
CritPt31.7%8.3%
LMArena Hard Prompts15451424
Mystery Game Puzzles71%6%
NYT Connections (extended)88.5%—
Chess Puzzles—18%
EBR-Bench71.4%—
DTBench98.9%—
LMCA68.2%—
Epoch Capabilities Index—150.13

Math Claude Opus 5.5 leads

Claude Opus 5.5: 92.4 (#2), Inkling-Small: 44.9 (#65)

Math benchmarks
BenchmarkClaude Opus 5.5Inkling-Small
FrontierMath (Tiers 1-3)91.2%46.3%
FrontierMath Tier 495%17.1%
OTIS Mock AIME 2024-2025100%90%
ProofBench100%6%
LMArena Math—1453

Knowledge Claude Opus 5.5 leads

Claude Opus 5.5: 66.6 (#9), Inkling-Small: 48.3 (#71)

Knowledge benchmarks
BenchmarkClaude Opus 5.5Inkling-Small
GPQA Diamond90.6%88.5%
SimpleQA Verified72.2%19.1%
LMArena Expert15641442

Multimodal Claude Opus 5.5 leads

Claude Opus 5.5: 56.5 (#2), Inkling-Small: 38.4 (#59)

Multimodal benchmarks
BenchmarkClaude Opus 5.5Inkling-Small
LMArena Vision—1235
Furniture Assembly83.3%—

Multilingual Claude Opus 5.5 leads

Claude Opus 5.5: 59.8 (#1), Inkling-Small: 51.7 (#102)

Multilingual benchmarks
BenchmarkClaude Opus 5.5Inkling-Small
LMArena Non-English15131400
LMArena Chinese15721458
LMArena Russian15321392
LMArena French—1438
LMArena German—1412
LMArena Japanese—1399
LMArena Korean—1355
LMArena Spanish—1426

Instruction Following Claude Opus 5.5 leads

Claude Opus 5.5: 80.1 (#2), Inkling-Small: 73.9 (#112)

Instruction Following benchmarks
BenchmarkClaude Opus 5.5Inkling-Small
LMArena Instruction Following15351397

Long Context Claude Opus 5.5 leads

Claude Opus 5.5: 47.3 (#18), Inkling-Small: 42.7 (#113)

Long Context benchmarks
BenchmarkClaude Opus 5.5Inkling-Small
LMArena Longer Query15401401

Writing & Preference Claude Opus 5.5 leads

Claude Opus 5.5: 78.7 (#3), Inkling-Small: 59.8 (#102)

Writing & Preference benchmarks
BenchmarkClaude Opus 5.5Inkling-Small
LMArena Text15181413
LMArena Creative Writing15381330
EQ-Bench Creative Writing20501491
LMArena Multi-Turn15201420

Frequently asked questions

Is Claude Opus 5.5 better than Inkling-Small?

Claude Opus 5.5 is the stronger model overall, scoring 68.5 to 46.5 on the Noometry Index. Inkling-Small costs 13× 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-Small?

Inkling-Small is cheaper. It lists at $0.45 per million input tokens and $1.20 per million output tokens; Claude Opus 5.5 lists at $4 and $20.

Is Claude Opus 5.5 or Inkling-Small better for coding?

Claude Opus 5.5 scores higher on coding benchmarks: 71.4 versus 43.3 in the Noometry coding category.

Which has the bigger context window?

Claude Opus 5.5 does, with 1M tokens against 524K.

How many benchmarks do Claude Opus 5.5 and Inkling-Small share?

24 benchmarks have published results for both models. Claude Opus 5.5 has 35 scored results on Noometry and Inkling-Small has 33.

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