ResearchLLM Verifications Leaderboard

Data as of · 78 models, 80 questions · reviewed by Suhas Bhairav · methodology

Head to head · tested 27 Oct 2026

Claude Haiku 5.5 vs Claude Sonnet 5.5: accuracy, speed and price

Similar accuracy; Claude Haiku 5.5 costs less per question.

AnthropicClaude Haiku 5.568.8% score · #26$0.00048 per question192 tok/sAnthropicClaude Sonnet 5.578.8% score · #7$0.0054 per question126 tok/s

Verdict

Built from the measurements below

  • Accuracy is too close to call: Claude Haiku 5.5 scored 68.8% and Claude Sonnet 5.5 78.8% on the same 80 questions, a gap within what chance alone could produce.
  • Claude Haiku 5.5 is 11× cheaper per question as billed ($0.00048 vs $0.0054), reasoning tokens included.
  • Claude Haiku 5.5 generates text 1.5× faster: 192 tokens per second against 126.

Which should you choose?

Choose Claude Haiku 5.5 for the lower cost per correct answer ($0.0007 against $0.0069) and faster streaming. Choose Claude Sonnet 5.5 for shorter outputs (about 456 tokens per question against 873). The widest subject gap is in engineering: Claude Sonnet 5.5 answered 13 of 15 correctly, Claude Haiku 5.5 10 of 15. With so few questions per subject, treat this as a lead to test on your own prompts, not a result.

Accuracy gap -10.0 points (z = -1.44). A winner is called only when z is at least 1.96, the usual 95% threshold. Speed, latency and price need a 10% margin.

Head to head

Same questions, same prompt, same API

MeasureClaude Haiku 5.5Claude Sonnet 5.5Edge
Verification scoreHigher is better68.8%78.8%Too close to call
Cost per questionLower is better$0.00048$0.0054Claude Haiku 5.5
Output speedHigher is better192126Claude Haiku 5.5
Time to first tokenLower is better0.7 s0.7 sSimilar
End-to-end response timeLower is better3.9 s6.2 sClaude Haiku 5.5
Tokens per questionLower is better873456Claude Sonnet 5.5
Context windowHigher is better1M1MSimilar

Side by side

Bars are scaled to the larger of the two values. The winner on each measure is marked in bold.

Every measure

Claude Haiku 5.5 first, Claude Sonnet 5.5 second

Verification scorehigher is better
Claude Haiku 5.568.8%
Claude Sonnet 5.578.8%
Cost per questionlower is better
Claude Haiku 5.5$0.00048
Claude Sonnet 5.5$0.0054
Output speedhigher is better
Claude Haiku 5.5192
Claude Sonnet 5.5126
Time to first tokenlower is better
Claude Haiku 5.50.7 s
Claude Sonnet 5.50.7 s
End-to-end response timelower is better
Claude Haiku 5.53.9 s
Claude Sonnet 5.56.2 s
Tokens per questionlower is better
Claude Haiku 5.5873
Claude Sonnet 5.5456
Context windowhigher is better
Claude Haiku 5.51M
Claude Sonnet 5.51M

Score vs. cost per question

Both models in color, every other model in grey

Most attractive quadrant0255075100$0.00001$0.0001$0.001$0.01$0.10Cost per question (USD, log) →Verification score (%) →Qwen3.8 2.4T A95BCommand AReka Flash 3Gemma 4 26B A4BGemma 4 31BQwen3.5 397B A17BHermes 4 405BMuse WonderGrok 4.7o3gpt-oss-20bMinistral 3 3B 2512Nova Micro 1.0Phi 4Granite 4.2 8BHy3GLM 5.3 FlashSolar Pro 4Trinity Large ThinkingMiniMax M3Mistral Large 4Claude Opus 5.5GPT-6.1 SolGemini 4 ArgonGPT-5.4GPT-6 Lunagpt-oss-120bLlama 4 Maverick

Specifications and pricing

From OpenRouter's catalogue, plus the leaderboard's test dates

SpecificationClaude Haiku 5.5Claude Sonnet 5.5
CreatorAnthropicAnthropic
Released7 Oct 202628 Sept 2026
Weights——
ReasoningYesYes
Inputtext, image, filetext, image, file
Outputtexttext
Context window1M tokens1M tokens
Knowledge cutoff——
List price in / out per 1M$0.1 / $0.5$2 / $10
Blended price per 1M (3:1)$0.20$4.00
Cheapest hostGoogle · $0.1 / $0.5Google · $2 / $10
Hosts on OpenRouter55
Last tested25 Oct 202625 Oct 2026

Compare any two models →

Claude Haiku 5.5 vs Claude Sonnet 5.5: frequently asked questions

Is Claude Haiku 5.5 better than Claude Sonnet 5.5?
On accuracy they are statistically tied: Claude Haiku 5.5 scored 68.8% and Claude Sonnet 5.5 78.8% on the same 80 questions from open datasets. Similar accuracy; Claude Haiku 5.5 costs less per question.
Which is cheaper, Claude Haiku 5.5 or Claude Sonnet 5.5?
Claude Haiku 5.5 is cheaper: $0.00048 per question as billed, against $0.0054. List prices: Claude Haiku 5.5 $0.1 in / $0.5 out, Claude Sonnet 5.5 $2 in / $10 out per million tokens.
Which is faster, Claude Haiku 5.5 or Claude Sonnet 5.5?
Claude Haiku 5.5 is faster at 192 output tokens per second, against 126. Time to first token: 0.7 s for Claude Haiku 5.5, 0.7 s for Claude Sonnet 5.5.
Which has the larger context window, Claude Haiku 5.5 or Claude Sonnet 5.5?
Both accept about the same amount of context: 1M and 1M tokens.