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A · closed · Claude Sonnet / Haiku

Claude Sonnet 4.6

Anthropic

B · closed · Claude Sonnet / Haiku

Claude Sonnet 5.5

Anthropic

0:0

overall capability wins (1 ties across 1 scored). Price/speed category wins do not decide overall. Tied overall.

  • Pricing0:3

Verdict

Claude Sonnet 5.5 is ~1.5x cheaper on a blended token basis than Claude Sonnet 4.6.

Cost for 1M in + 250K out

Illustrative chat workload at primary-provider list prices.

Claude Sonnet 4.6
$6.75
Claude Sonnet 5.5
$4.50

Claude Sonnet 5.5 is about 1.5x cheaper on this workload.

Price per 1M tokens

Full comparison

Organization

Anthropic

Anthropic

Family

Claude Sonnet / Haiku

Claude Sonnet / Haiku

License

Proprietary

Proprietary

Open weights

No

No

Release

Mar 18, 2026

Sep 28, 2026

Knowledge cutoff

-

-

API / provider

Anthropic

Anthropic

Modalities

text, image → text

text, image → text

Specs

Context window

1M

1M

tie

Max output

64K

-

—

Parameters

—

—

—

Pricing

Input $/1M

$3

$2

B +$1

Output $/1M

$15

$10

B +$5

Blended $/1M (3∶1)

$6

$4

B +$2

Speed

tok/s

90

-

—

TTFT (s)

0.4

-

—

Reasoning

MMLU-Pro

—

—

—

GPQA Diamond

87.5

—

—

Humanity's Last Exam

33.6

—

—

AIME 2025

—

—

—

MATH-500

—

—

—

Humanity's Last Exam (with tools)

—

64.5

—

AA-Omniscience Accuracy

40.9

—

—

AA-LCR v1.1

80.0

—

—

CritPt

3.1

—

—

MMMU-Pro

73.3

—

—

IFBench

56.6

—

—

Chartography

—

61.6

—

Chartography (With Tools)

—

—

—

Coding

SWE-bench Verified

—

—

—

SWE-bench Pro

—

—

—

SWE-bench Multilingual

—

—

—

LiveCodeBench

—

—

—

Terminal-Bench 2.1

71.2

—

—

Aider Polyglot

—

—

—

Terminal-Bench 3

—

—

—

BigCodeBench

—

—

—

SciCode

50.1

—

—

CursorBench

—

—

—

SWE-Rebench

54.5

—

—

NL2Repo-Bench

—

—

—

DeepSWE

—

—

—

WebDev Arena

1,521

—

—

Terminal-Bench 4.0

—

70.6

—

CursorBench 4.0

—

55.5

—

FrontierCode v1.1 (Main)

—

52.1

—

Arena

LMArena Elo

1,473

—

—

Claude Sonnet 4.6

Context
1M / 64K out
Parameters
—
Price
$3 / $15
Speed
90 tok/s · 0.4s TTFT
Modalities
text, image → text
License
Proprietary

Prior Sonnet generation with strong coding and long-context support before Sonnet 5.

Claude Sonnet 5.5

Context
1M
Parameters
—
Price
$2 / $10
Speed
—
Modalities
text, image → text
License
Proprietary

Anthropic's September 2026 Sonnet model for everyday coding, agentic work, and document creation. It supports text and image input, a 1M context window, and standard API rates of $2/$10 per 1M input/output tokens. Published benchmark results vary by effort and, for agent evaluations, harness; the cited Chartography score is no-tools.

Benchmark charts

Winner bars are emphasized. Per-benchmark deltas sit above each chart.

These two models have no overlapping published benchmarks in our dataset. Compare specs and pricing instead.

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