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#178

Claude Sonnet 5.5

Anthropic Release: 2026-09-29 Tested on: 2026-09-30 22:56 anthropic/claude-sonnet-5.5::low
~1T total (~100B active)MoEClosedEstimated
(max) (xhigh) (high) (medium) (low)

Summary

Claude Sonnet 5.5 scores 6.9 on AI BENCHY and ranks #178. It has 10.0 reliability, a 46.4% pass rate, $0.909 total cost, and 7.46s average response time.

What makes Claude Sonnet 5.5 unique: It stands out most in Combined, where it ranks #3, while Coding is its weakest area at #17.

Model facts

Researched on 2026-09-29

Estimated
Parameters
~1T total (~100B active)
Architecture
MoE
Availability
Closed
License
-

Best estimate from public evidence; the vendor did not disclose every value. Vendor does not disclose parameter counts or architecture. Low-confidence catalog estimates carry forward the prior Claude Sonnet 5 family estimates; the announcement establishes identity and API availability, not these counts. Thinking is always on; OpenRouter lists low, medium, high, xhigh, and max efforts.

Parameter source Availability source

Score

6.9

Consistency

9.4

Reliability

10.0

Total Cost (Current Price)

$0.909

Total Output Tokens

32,443

Total Input Tokens

291,853

Input Price

$2.000 / 1M

Output Price

$10.000 / 1M

Cache Read Price

$0.200 / 1M

Cache Write Price

$2.500 / 1M

Cache prices apply to input tokens. Reads reuse cached prompts; writes store them and can cost extra. Output tokens use the output price.

Tests Correct

Wrong Tests: 13

Attempt pass rate: 46.4%

Flaky tests

2

Flaky tests had mixed outcomes across runs (at least one pass and one fail).

Response Time (avg)

7.46s

Response Time (max): 46.61s

Response Time (total): 171.47s

Extra formatting: 5 Did not follow instructions: 5 Invalid tool call: 1 No answer: 1 Wrong answer: 1

Hamster playing table tennis

Prompt: Create a detailed SVG illustration of a hamster playing table tennis.

#178 Claude Sonnet 5.5

low
Cost
$0.020
Time
15.3s
Tokens
2,077 tok

Price History

Historical pricing data for this model from OpenRouter.

Date Input Price Output Price Cache Read Price Cache Write Price
2026-10-01 18:33 $2.000 / 1M $10.000 / 1M $0.200 / 1M $2.500 / 1M

Charts

Choose the first model, then click a second model to open a side-by-side page.

Total Output Tokens

Score vs Total Output Tokens

Quick Compare

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Category Breakdown

Category Score Consistency Tests Correct
Agentic 10.0 10.0
Anti-AI Tricks 6.5 10.0
Coding 3.2 9.7
Combined 7.9 6.9
Data parsing and extraction 10.0 10.0
Domain specific 3.0 10.0
General Intelligence 4.8 3.2
Instructions following 6.3 10.0
Puzzle Solving 7.7 10.0
Tool Calling 10.0 10.0
Trivia 3.0 10.0

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