Noometry

Model comparison

Claude Haiku 5.5 vs Step 3.5 Flash

Claude Haiku 5.5 is the stronger model overall, scoring 49.5 to 42.3 on the Noometry Index.

Last verified . 1 shared benchmarks.

Claude Haiku 5.5 Anthropic

49.5

Rank #52 Confirmed

Step 3.5 Flash StepFun

42.3

Rank #116 Confirmed

Summary

  • They share 1 benchmark with published results for both. Claude Haiku 5.5 scores higher in 4 categories and Step 3.5 Flash in 0 categories; 4 gaps are clear of the uncertainty.
  • The widest gap is in math, where Claude Haiku 5.5 leads 73.6 to 42.6.
  • The biggest single-benchmark swing is NYT Connections (extended): 65.7% for Claude Haiku 5.5 and 28.4% for Step 3.5 Flash.
  • Step 3.5 Flash is cheaper at $0.10 / $0.30 per million input/output tokens, against $0.10 / $0.50 for Claude Haiku 5.5.
  • Claude Haiku 5.5 accepts more context: 1M tokens versus 256K.
  • Step 3.5 Flash has downloadable open weights; the other is API-only.

Side by side

Claude Haiku 5.5Step 3.5 Flash
ProviderAnthropicStepFun
Noometry Index49.542.3
Released2026-10-072026-01-29
WeightsProprietaryOpen
Context window1M256K
Max output128K256K
Input $ / M tokens$0.10$0.10
Output $ / M tokens$0.50$0.30
Results tracked919

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Category by category

Coding Claude Haiku 5.5 leads

Claude Haiku 5.5: 49.2 (#50), Step 3.5 Flash: 42.4 (#105)

BenchmarkClaude Haiku 5.5Step 3.5 Flash
LMArena WebDev1587—
LMArena Coding—1436

Reasoning Claude Haiku 5.5 leads

Claude Haiku 5.5: 35.2 (#69), Step 3.5 Flash: 22.2 (#202)

BenchmarkClaude Haiku 5.5Step 3.5 Flash
NYT Connections (extended)65.7%28.4%
LMArena Hard Prompts—1411
Mystery Game Puzzles30%—

Math Claude Haiku 5.5 leads

Claude Haiku 5.5: 73.6 (#18), Step 3.5 Flash: 42.6 (#84)

BenchmarkClaude Haiku 5.5Step 3.5 Flash
FrontierMath (Tiers 1-3)75.1%—
FrontierMath Tier 446.3%—
MathArena Final-Answer Competitions—66.8%
OTIS Mock AIME 2024-202598.9%—
LMArena Math—1408

Knowledge Claude Haiku 5.5 leads

Claude Haiku 5.5: 50.8 (#70), Step 3.5 Flash: 39.6 (#132)

BenchmarkClaude Haiku 5.5Step 3.5 Flash
GPQA Diamond89.6%—
SimpleQA Verified23.8%—
LMArena Expert—1421

Multimodal Not comparable

Claude Haiku 5.5: 43.7 (#21), Step 3.5 Flash: —

BenchmarkClaude Haiku 5.5Step 3.5 Flash
Furniture Assembly47.5%—

Multilingual Not comparable

Claude Haiku 5.5: —, Step 3.5 Flash: 50.5 (#119)

BenchmarkClaude Haiku 5.5Step 3.5 Flash
LMArena Non-English—1385
LMArena Chinese—1447
LMArena French—1421
LMArena German—1405
LMArena Japanese—1354
LMArena Korean—1352
LMArena Russian—1385
LMArena Spanish—1419

Instruction Following Not comparable

Claude Haiku 5.5: —, Step 3.5 Flash: 73.1 (#124)

BenchmarkClaude Haiku 5.5Step 3.5 Flash
LMArena Instruction Following—1385

Long Context Not comparable

Claude Haiku 5.5: —, Step 3.5 Flash: 42.8 (#117)

BenchmarkClaude Haiku 5.5Step 3.5 Flash
LMArena Longer Query—1402

Writing & Preference Not comparable

Claude Haiku 5.5: —, Step 3.5 Flash: 58.8 (#113)

BenchmarkClaude Haiku 5.5Step 3.5 Flash
LMArena Text—1403
LMArena Creative Writing—1357
LMArena Multi-Turn—1405

Frequently asked questions

Is Claude Haiku 5.5 better than Step 3.5 Flash?

Claude Haiku 5.5 is the stronger model overall, scoring 49.5 to 42.3 on the Noometry Index.

Which is cheaper, Claude Haiku 5.5 or Step 3.5 Flash?

Step 3.5 Flash is cheaper. It lists at $0.10 per million input tokens and $0.30 per million output tokens; Claude Haiku 5.5 lists at $0.10 and $0.50.

Is Claude Haiku 5.5 or Step 3.5 Flash better for coding?

Claude Haiku 5.5 scores higher on coding benchmarks: 49.2 versus 42.4 in the Noometry coding category.

Which has the bigger context window?

Claude Haiku 5.5 does, with 1M tokens against 256K.

How many benchmarks do Claude Haiku 5.5 and Step 3.5 Flash share?

1 benchmark has published results for both models. Claude Haiku 5.5 has 9 scored results on Noometry and Step 3.5 Flash has 19.

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