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A · closed · Claude Sonnet / Haiku

Claude Sonnet 4.5

Anthropic

B · closed · Claude Sonnet / Haiku

Claude Sonnet 4.6

Anthropic

0:4

overall capability wins (1 ties across 5 scored). Claude Sonnet 4.6 leads overall.

  • Coding0:2
  • Arena0:1
  • Speed0:1
  • Specs0:1

Verdict

Claude Sonnet 4.6 leads coding (widest gap: +135.5 on WebDev Elo); Claude Sonnet 4.6 ranks higher on LMArena (+18 Elo); Claude Sonnet 4.6 offers ~5.0x larger context (1M vs 200K).

  • Claude Sonnet 4.6 leads coding (widest gap: +135.5 on WebDev Elo)
  • Claude Sonnet 4.6 ranks higher on LMArena (+18 Elo)
  • Claude Sonnet 4.6 offers ~5.0x larger context (1M vs 200K)

Cost for 1M in + 250K out

Illustrative chat workload at primary-provider list prices.

Claude Sonnet 4.5
$6.75
Claude Sonnet 4.6
$6.75

Price per 1M tokens

Full comparison

Organization

Anthropic

Anthropic

Family

Claude Sonnet / Haiku

Claude Sonnet / Haiku

License

Proprietary

Proprietary

Open weights

No

No

Release

Sep 29, 2025

Mar 18, 2026

Knowledge cutoff

-

-

API / provider

Anthropic

Anthropic

Modalities

text, image → text

text, image → text

Specs

Context window

200K

1M

B +800K

Max output

64K

64K

tie

Parameters

—

—

—

Pricing

Input $/1M

$3

$3

tie

Output $/1M

$15

$15

tie

Blended $/1M (3∶1)

$6

$6

tie

Speed

tok/s

85

90

B +5.00

TTFT (s)

0.4

0.4

tie

Reasoning

MMLU-Pro

—

—

—

GPQA Diamond

—

87.5

—

Humanity's Last Exam

—

33.6

—

AIME 2025

—

—

—

MATH-500

—

—

—

Humanity's Last Exam (with tools)

—

—

—

AA-Omniscience Accuracy

—

40.9

—

AA-LCR v1.1

—

80.0

—

CritPt

—

3.1

—

MMMU-Pro

—

73.3

—

IFBench

—

56.6

—

Chartography

—

—

—

Chartography (With Tools)

—

—

—

Coding

SWE-bench Verified

—

—

—

SWE-bench Pro

43.6

—

—

SWE-bench Multilingual

67.0

—

—

LiveCodeBench

—

—

—

Terminal-Bench 2.1

—

71.2

—

Aider Polyglot

—

—

—

Terminal-Bench 3

—

—

—

BigCodeBench

—

—

—

SciCode

—

50.1

—

CursorBench

—

—

—

SWE-Rebench

52.4

54.5

B +2.1 pts

NL2Repo-Bench

—

—

—

DeepSWE

—

—

—

WebDev Arena

1,386

1,521

B +136 Elo

Terminal-Bench 4.0

—

—

—

CursorBench 4.0

—

—

—

FrontierCode v1.1 (Main)

—

—

—

Arena

LMArena Elo

1,455

1,473

B +18 Elo

Claude Sonnet 4.5

Context
200K / 64K out
Parameters
—
Price
$3 / $15
Speed
85 tok/s · 0.4s TTFT
Modalities
text, image → text
License
Proprietary

Prior Sonnet workhorse for coding agents before the 4.6 / 5 line.

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.

Benchmark charts

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

Coding

SWE-Rebench: B +2.1WebDev Elo: B +136

Arena

Arena Elo: B +18

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