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Claude Sonnet 4.5

Anthropicfamily · Claude

Claude Sonnet 4.5 is Anthropic’s most advanced Sonnet model to date, optimized for real-world agents and coding workflows. It delivers state-of-the-art performance on coding benchmarks such as SWE-bench Verified, with...

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data quality67

Updated 4 h ago · first seen 11 Sept 2026

model_01M293VBDY6MGVRK53W1PBAGB3

Overview

Identity

Canonical model
Yesidentity confidence: mediumOne row per real model release. Artifacts (checkpoints, quantisations, conversions) and folded evaluation variants point here.
Official checkpoints
None recorded — closed weightsofficial_checkpoints = hf_repo identifiers carried by the model itself; artifacts are separate entities pointing here through canonical_id.
Artifacts
None recordedSeparate entities (checkpoint · quantization · conversion · packaging) pointing to this model through canonical_id.
Provider deployments
2
API aliases
anthropic/claude-sonnet-4.5claude-4-5-sonnetclaude-4-5-sonnet-thinkingclaude-sonnet-4-5-20250929Identifiers under which providers and evaluators refer to this model.
Folded evaluation variants
1Effort / thinking variants (…-high, …-non-reasoning) are result configurations of this model, not separate models. Their old URLs redirect here.

Openness

Closed / proprietary— weights not available; 7 dimensions unknown.

Weights are not available; the model is reachable only through an API or a product.

  • Weights

    No

  • Inference code

    —

  • Training code

    —

  • Training data

    —

  • Dataset

    —

  • Commercial use

    —

  • Redistribution

    —

  • Derivatives

    —

dimensions marked null are unknown, not false

Key facts

Release date

Source:OpenRouter public model & pricing listingT2observed 14 h agomedium

Status

Source:Claude Developer Platform docsT1observed 14 h agohigh

Knowledge cutoff

Source:OpenRouter public model & pricing listingT2observed 14 h agomedium

Retirement date

Source:Claude Developer Platform docsT1observed 14 h agohigh

Openrouter id

Source:OpenRouter public model & pricing listingT2observed 14 h agomedium

Architecture

Tokenizer

Source:OpenRouter public model & pricing listingT2observed 14 h agomedium

Capabilities

Modalities

Modalities
documentimagetext
Input
documentimagetext
Output
text

Capabilities

  • Tool calling

    Yes

    OpenRouter public model & pricing listing · T2

  • Structured output

    Yes

    OpenRouter public model & pricing listing · T2

  • Reasoning

    Yes

    OpenRouter public model & pricing listing · T2

  • Vision

    Yes

    OpenRouter public model & pricing listing · T2

  • Audio

    Unavailable

  • Fine-tuning available

    Unavailable

Context window

Source:OpenRouter public model & pricing listingT2observed 14 h agomedium

Max output

Source:OpenRouter public model & pricing listingT2observed 14 h agomedium

Knowledge cutoff

Source:OpenRouter public model & pricing listingT2observed 14 h agomedium

Tokenizer

Source:OpenRouter public model & pricing listingT2observed 14 h agomedium

Benchmarks34

Compare with another model →

Comparable same task and conditions · Partially comparable same task, conditions differ (effort, temperature, judge) · Not comparable different variant or metric

Benchmark results grouped by comparability group
Benchmark · groupBest scoreTrustConfigurationResultsvs leaderEvaluatedSource
Terminal-Benchagentic · accuracy · variant=v2.1 · evaluator=Artificial AnalysisIndependentevaluatorArtificial Analysisvariantv2.1reasoningonconditions differ across rows → partially comparable2non-primary groupobs. 12 Sept 2026artificialanalysis.aiT2
Terminal-Benchagentic · accuracy · variant=hard · evaluator=Artificial AnalysisIndependentevaluatorArtificial Analysisvarianthardreasoningonconditions differ across rows → partially comparable4−30.3 ptvs gpt-5.6-solobs. 12 Sept 2026artificialanalysis.aiT2
Terminal-Benchagentic · accuracy · variant=v4.0 · evaluator=Artificial AnalysisIndependentevaluatorArtificial Analysisvariantv4.0reasoningonconditions differ across rows → partially comparable2non-primary groupobs. 12 Sept 2026artificialanalysis.aiT2
τ²-benchagentic · pass^1 · variant=Telecom · evaluator=Artificial AnalysisIndependentevaluatorArtificial AnalysisvariantTelecomreasoningonconditions differ across rows → partially comparable2non-primary groupobs. 12 Sept 2026artificialanalysis.aiT2
τ²-benchagentic · pass^1 · evaluator=Artificial AnalysisIndependentevaluatorArtificial Analysisreasoningonconditions differ across rows → partially comparable2−21.1 ptvs Z.ai GLM 5.2obs. 11 Sept 2026artificialanalysis.aiT2
SciCodecoding · accuracy · evaluator=Artificial AnalysisIndependentevaluatorArtificial Analysisreasoningonconditions differ across rows → partially comparable2−17.4 ptvs Claude Fable 5.1obs. 12 Sept 2026artificialanalysis.aiT2
Artificial Analysis Intelligence Indexcomposite · indexIndependentreasoningonversion4.3conditions differ across rows → partially comparable4−32.2vs Claude Fable 5.1obs. 12 Sept 2026artificialanalysis.aiT2
IFBenchinstruction-following · accuracy · evaluator=Artificial AnalysisIndependentevaluatorArtificial Analysisreasoningonconditions differ across rows → partially comparable4−26.0 ptvs Grok 4.3obs. 12 Sept 2026artificialanalysis.aiT2
Humanity's Last Examknowledge · accuracy · evaluator=Artificial AnalysisIndependentevaluatorArtificial Analysisreasoningonconditions differ across rows → partially comparable4−41.3 ptvs Claude Fable 5.1obs. 12 Sept 2026artificialanalysis.aiT2
MMMU-Promultimodal · accuracy · evaluator=Artificial AnalysisIndependentevaluatorArtificial Analysisreasoningonconditions differ across rows → partially comparable4−18.1 ptvs gpt-6-astraobs. 12 Sept 2026artificialanalysis.aiT2
GPQA Diamondreasoning · accuracy · variant=Diamond · evaluator=Artificial AnalysisIndependentevaluatorArtificial AnalysisvariantDiamondreasoningonconditions differ across rows → partially comparable2non-primary groupobs. 12 Sept 2026artificialanalysis.aiT2
GPQA Diamondreasoning · accuracy · variant=GPQA Diamond · evaluator=Artificial AnalysisIndependentevaluatorArtificial AnalysisvariantGPQA Diamondreasoningonconditions differ across rows → partially comparable2−12.8 ptvs gpt-6-astraobs. 11 Sept 2026artificialanalysis.aiT2

Current rows only, grouped by benchmark → canonical metric → comparability group (task configuration). Effort variants folded into this model appear as rows of the same group. 34 current rows in total. “vs leader” compares with the current leader of the benchmark's primary group only; other groups are not directly comparable. Comparability rules →

Providers & Pricing5

All offers in the price terminal →
Provider deployments, cheapest output first
ProviderContextInput / 1MCached inCache writeOutput / 1MNative unitsStatusObservedSource
Anthropic APIcheapest outputanthropic/claude-sonnet-4.5:batch1Mout 64K$0.15$1.88—active5 h agosince 11 Sept 2026openrouter.aiT2
OpenRouteranthropic/claude-sonnet-4.5:batch1Mout 64K$0.15$1.88—active2 h agosince 12 Sept 2026openrouter.aiT2
Anthropic API—$0.30$3.75cache_write_1h_per_mtok=6active14 h agosince 11 Sept 2026platform.claude.comT1
Anthropic APIanthropic/claude-sonnet-4.51Mout 64K$0.30$3.75—active5 h agosince 11 Sept 2026openrouter.aiT2
OpenRouteranthropic/claude-sonnet-4.51Mout 64K$0.30$3.75—active2 h agosince 12 Sept 2026openrouter.aiT2

USD per 1M tokens as published by each provider; native units (per-request fees, flex/priority tiers) are kept verbatim. Rows are append-only — every price change is kept in the history below. Cost of a workload →

Price history

Step lines per provider; amber markers are recorded changes. Click a marker or a row for the evidence behind that price.

Output price · USD / 1M tokens 2 providers

Output price history of Claude Sonnet 4.5$0$5$10$15$20Sept 26Sept 26Sept 26Sept 26Anthropic API: first observed → $15 · 11 Sept 2026Anthropic API: $15 → $7.5 · 11 Sept 2026OpenRouter: first observed → $15 · 12 Sept 2026OpenRouter: $15 → $7.5 · 12 Sept 2026
  • Anthropic API
  • OpenRouter
  • OpenRouter$15 → $7.512 Sept 2026
  • OpenRouterfirst observed $1512 Sept 2026
  • Anthropic API$15 → $7.511 Sept 2026
  • Anthropic APIfirst observed $1511 Sept 2026

Input price · USD / 1M tokens 2 providers

Input price history of Claude Sonnet 4.5$0$1$2$3$4Sept 26Sept 26Sept 26Sept 26Anthropic API: first observed → $3 · 11 Sept 2026Anthropic API: $3 → $1.5 · 11 Sept 2026OpenRouter: first observed → $3 · 12 Sept 2026OpenRouter: $3 → $1.5 · 12 Sept 2026
  • Anthropic API
  • OpenRouter
  • OpenRouter$3 → $1.512 Sept 2026
  • OpenRouterfirst observed $312 Sept 2026
  • Anthropic API$3 → $1.511 Sept 2026
  • Anthropic APIfirst observed $311 Sept 2026

Versions & Artifacts0

Version history

Status1 change

11 Sept 2026→11 Sept 2026current

Context windowfirst observation only

11 Sept 2026current

Knowledge cutofffirst observation only

11 Sept 2026current

Max outputfirst observation only

11 Sept 2026current

Opennessfirst observation only

11 Sept 2026current

Each hop is a claim: click a value for its source, tier and observation time. Nothing is overwritten — a new observation closes the previous claim.

Artifacts 0

No artifact (checkpoint, quantisation, conversion or packaging) points to this model yet.

Timeline22

Full timeline →

Change history

Temporal, append-only claims: a new observation closes the previous claim instead of overwriting it. Rewind the record with the as-of picker.
2 claims · 1 propertiesShow all properties

Aa median output tokens per secondmetric.aa_median_output_tokens_per_second2

Claim history for Aa median output tokens per second
ValueValid from → toStatusSourceConfidenceExtractor
38 → currentcurrentArtificial AnalysisT2mediumdeterministic
41.7 → currentcurrentArtificial AnalysisT2mediumdeterministic

Claims are temporal and append-only: a new observation closes the previous claim (valid_to) instead of overwriting it. Conflicting claims from different sources are kept side by side and flagged — never averaged. Methodology →

Provenance

Attributed facts

26

Source tiers

T1T25 / 21

Freshest observation

4 h ago

Conflicts

1 flagged

Source documents 4

Source documents
SourceDocumentTypeTierLast observedSnapshots
Claude Developer Platform docsdocs.claude.com/en/docs/about-claude/model-deprecations.md model_docsT1· Official3 h ago1
Claude Developer Platform docsdocs.claude.com/en/docs/about-claude/pricing.md pricingT1· Official3 h ago1
OpenRouter public model & pricing listingopenrouter.ai/api/v1/models catalogueT2· Quality secondary2 h ago10
Artificial Analysisartificialanalysis.ai/leaderboards/models leaderboardT2· Quality secondary4 h ago2

Tier 1 = official/primary, 2 = quality secondary, 3 = community, 4 = unverified. Every snapshot is archived; see all sources and the methodology.

Data quality (67/100) measures how well AI Atlas knows this entity — completeness, primary-source ratio, freshness, conflicts — never how good the model is. Methodology →