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Anthropic has launched a newer model, Claude Sonnet 4.6 (max), we suggest considering this model instead.

For more information, see Comparison of Claude Sonnet 4.6 (max) to other models and API provider benchmarks for Claude Sonnet 4.6 (max).

Claude 4.5 Sonnet (Reasoning) logo

Claude 4.5 Sonnet (Reasoning) Intelligence, Performance & Price Analysis

Anthropic

Proprietary model

Released September 2025

Model summary

Intelligence

Artificial Analysis Intelligence Index

43
4 out of 4 units for Intelligence.

Speed

Output tokens per second

48.6
2 out of 4 units for Speed.

Input Price

USD per 1M tokens

$3.00
3 out of 4 units for Input Price.

Output Price

USD per 1M tokens

$15.00
3 out of 4 units for Output Price.

Verbosity

Output tokens from Intelligence Index

64M
4 out of 4 units for Verbosity.

Metrics are compared against models of the same class:

  • Non-reasoning models → compared only with other non-reasoning models
  • Reasoning models → compared across both reasoning and non-reasoning
  • Open weights models → compared only with other open weights models of the same size class:
    • Tiny: ≤4B parameters
    • Small: 4B–40B parameters
    • Medium: 40B–150B parameters
    • Large: >150B parameters
  • Proprietary models → compared across proprietary and open weights models of the same price range, using a blended 3:1 input/output price ratio:
    • <$0.15 per 1M tokens
    • $0.15–$1 per 1M tokens
    • >$1 per 1M tokens
Technical specifications
ReasoningYes

This page shows the reasoning version of this model.

A non-reasoning variant may also exist.

Input modality

Supports: text, image

Output modality

Supports: text

Knowledge cutoffJul 1, 2025
Context window1m
~1500 A4 pages of size 12 Arial font

Claude 4.5 Sonnet (Reasoning) is amongst the leading models in intelligence, but somewhat expensive when comparing to other models of similar price. It's also slower than average and very verbose. The model supports text and image input, outputs text, and has a 1m tokens context window with knowledge up to July 2025.

Claude 4.5 Sonnet (Reasoning) scores 43 on the Artificial Analysis Intelligence Index, placing it well above average among comparable models (averaging 28). When evaluating the Intelligence Index, it generated 64M tokens, which is very verbose in comparison to the average of 13M.

Pricing for Claude 4.5 Sonnet (Reasoning) is $3.00 per 1M input tokens (somewhat expensive, average: $1.60) and $15.00 per 1M output tokens (somewhat expensive, average: $10.00). In total, it cost $1458.79 to evaluate Claude 4.5 Sonnet (Reasoning) on the Intelligence Index.

At 49 tokens per second, Claude 4.5 Sonnet (Reasoning) is slower than average (62).

Navigation

IntelligenceOpennessIntelligence Index ComparisonsIntelligence Index Token Use & CostContext WindowPricingPerformance SummarySpeedLatencyEnd-to-End Response TimeModel Size (Open Weights Models Only)Comparisons

Intelligence

Artificial Analysis Intelligence Index

Artificial Analysis Intelligence Index v4.0 incorporates 10 evaluations: GDPval-AA, 𝜏²-Bench Telecom, Terminal-Bench Hard, SciCode, AA-LCR, AA-Omniscience, IFBench, Humanity's Last Exam, GPQA Diamond, CritPt
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Reasoning models are indicated by a lightbulb icon.

Artificial Analysis Intelligence Index v4.0 includes: GDPval-AA, 𝜏²-Bench Telecom, Terminal-Bench Hard, SciCode, AA-LCR, AA-Omniscience, IFBench, Humanity's Last Exam, GPQA Diamond, CritPt. See Intelligence Index methodology for further details, including a breakdown of each evaluation and how we run them.

Artificial Analysis Intelligence Index by Open Weights / Proprietary

Artificial Analysis Intelligence Index v4.0 incorporates 10 evaluations: GDPval-AA, 𝜏²-Bench Telecom, Terminal-Bench Hard, SciCode, AA-LCR, AA-Omniscience, IFBench, Humanity's Last Exam, GPQA Diamond, CritPt
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Proprietary
Open Weights
Reasoning models are indicated by a lightbulb icon.

Artificial Analysis Intelligence Index v4.0 includes: GDPval-AA, 𝜏²-Bench Telecom, Terminal-Bench Hard, SciCode, AA-LCR, AA-Omniscience, IFBench, Humanity's Last Exam, GPQA Diamond, CritPt. See Intelligence Index methodology for further details, including a breakdown of each evaluation and how we run them.

Indicates whether the model weights are available. Models are labelled as 'Commercial Use Restricted' if the weights are available but commercial use is limited (typically requires obtaining a paid license).

Intelligence Evaluations

Intelligence evaluations measured independently by Artificial Analysis; Higher is better
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Results claimed by AI Lab (not yet independently verified)
GDPval-AA (Agentic Real-World Work Tasks, (ELO-500)/2000)
Terminal-Bench Hard (Agentic Coding & Terminal Use)
𝜏²-Bench Telecom (Agentic Tool Use)
AA-LCR (Long Context Reasoning)
AA-Omniscience Accuracy (Knowledge)
AA-Omniscience Non-Hallucination Rate (1 - Hallucination Rate)
Humanity's Last Exam (Reasoning & Knowledge)
GPQA Diamond (Scientific Reasoning)
SciCode (Coding)
IFBench (Instruction Following)
CritPt (Physics Reasoning)
MMMU Pro (Visual Reasoning)
Reasoning models are indicated by a lightbulb icon.

While model intelligence generally translates across use cases, specific evaluations may be more relevant for certain use cases.

Artificial Analysis Intelligence Index v4.0 includes: GDPval-AA, 𝜏²-Bench Telecom, Terminal-Bench Hard, SciCode, AA-LCR, AA-Omniscience, IFBench, Humanity's Last Exam, GPQA Diamond, CritPt. See Intelligence Index methodology for further details, including a breakdown of each evaluation and how we run them.

Openness

Artificial Analysis Openness Index: Results

Openness Index assesses model openness on a 0 to 100 normalized scale (higher is more open)
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Intelligence Index Comparisons

Intelligence vs. Price

Artificial Analysis Intelligence Index; Price: USD per 1M Tokens
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Most attractive quadrant
Alibaba
Anthropic
DeepSeek
Google
Kimi
NVIDIA
OpenAI
xAI
Z AI
Reasoning models are indicated by a lightbulb icon.

While higher intelligence models are typically more expensive, they do not all follow the same price-quality curve.

Artificial Analysis Intelligence Index v4.0 includes: GDPval-AA, 𝜏²-Bench Telecom, Terminal-Bench Hard, SciCode, AA-LCR, AA-Omniscience, IFBench, Humanity's Last Exam, GPQA Diamond, CritPt. See Intelligence Index methodology for further details, including a breakdown of each evaluation and how we run them.

Price per token, represented as USD per million Tokens. Price is a blend of Input & Output token prices (3:1 ratio).

Figures represent performance of the model's first-party API (e.g. OpenAI for o1) or the median across providers where a first-party API is not available (e.g. Meta's Llama models).

Intelligence Index Token Use & Cost

Output Tokens Used to Run Artificial Analysis Intelligence Index

Tokens used to run all evaluations in the Artificial Analysis Intelligence Index
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Reasoning Tokens
Answer Tokens
Reasoning models are indicated by a lightbulb icon.

The number of tokens required to run all evaluations in the Artificial Analysis Intelligence Index (excluding repeats).

Cost to Run Artificial Analysis Intelligence Index

Cost (USD) to run all evaluations in the Artificial Analysis Intelligence Index
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Input Cost
Reasoning Cost
Output Cost
Reasoning models are indicated by a lightbulb icon.

The cost to run the evaluations in the Artificial Analysis Intelligence Index, calculated using the model's input and output token pricing and the number of tokens used across evaluations (excluding repeats).

Context Window

Context Window

Context Window: Tokens Limit; Higher is better
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Reasoning models are indicated by a lightbulb icon.

Larger context windows are relevant to RAG (Retrieval Augmented Generation) LLM workflows which typically involve reasoning and information retrieval of large amounts of data.

Maximum number of combined input & output tokens. Output tokens commonly have a significantly lower limit (varied by model).

Pricing

Pricing: Input and Output Prices

Price: USD per 1M Tokens
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Input price
Output price
Reasoning models are indicated by a lightbulb icon.

Price per token included in the request/message sent to the API, represented as USD per million Tokens.

Figures represent performance of the model's first-party API (e.g. OpenAI for o1) or the median across providers where a first-party API is not available (e.g. Meta's Llama models).

Intelligence vs. Price (Log Scale)

Artificial Analysis Intelligence Index; Price: USD per 1M Tokens; Inspired by prior analysis by Swyx
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Most attractive quadrant
Alibaba
Anthropic
DeepSeek
Google
Kimi
NVIDIA
OpenAI
xAI
Z AI
Reasoning models are indicated by a lightbulb icon.

While higher intelligence models are typically more expensive, they do not all follow the same price-quality curve.

Artificial Analysis Intelligence Index v4.0 includes: GDPval-AA, 𝜏²-Bench Telecom, Terminal-Bench Hard, SciCode, AA-LCR, AA-Omniscience, IFBench, Humanity's Last Exam, GPQA Diamond, CritPt. See Intelligence Index methodology for further details, including a breakdown of each evaluation and how we run them.

Price per token, represented as USD per million Tokens. Price is a blend of Input & Output token prices (3:1 ratio).

Figures represent performance of the model's first-party API (e.g. OpenAI for o1) or the median across providers where a first-party API is not available (e.g. Meta's Llama models).

 Pricing Comparison of Claude 4.5 Sonnet (Reasoning) API Providers

Speed

Measured by Output Speed (tokens per second)

Output Speed

Output Tokens per Second; Higher is better
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Reasoning models are indicated by a lightbulb icon.

Tokens per second received while the model is generating tokens (ie. after first chunk has been received from the API for models which support streaming).

Figures represent performance of the model's first-party API (e.g. OpenAI for o1) or the median across providers where a first-party API is not available (e.g. Meta's Llama models).

Output Speed vs. Price

Output Speed: Output Tokens per Second; Price: USD per 1M Tokens
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Most attractive quadrant
Alibaba
Anthropic
DeepSeek
Google
Kimi
NVIDIA
OpenAI
xAI
Z AI
Reasoning models are indicated by a lightbulb icon.

Tokens per second received while the model is generating tokens (ie. after first chunk has been received from the API for models which support streaming).

Price per token, represented as USD per million Tokens. Price is a blend of Input & Output token prices (3:1 ratio).

Latency

Measured by Time (seconds) to First Token

Latency: Time To First Answer Token

Seconds to First Answer Token Received; Accounts for Reasoning Model 'Thinking' time
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Input processing
Thinking (reasoning models, when applicable)
Reasoning models are indicated by a lightbulb icon.

Time to first answer token received, in seconds, after API request sent. For reasoning models, this includes the 'thinking' time of the model before providing an answer. For models which do not support streaming, this represents time to receive the completion.

End-to-End Response Time

Seconds to output 500 Tokens, calculated based on time to first token, 'thinking' time for reasoning models, and output speed

End-to-End Response Time

Seconds to Output 500 Tokens, including reasoning model 'thinking' time; Lower is better
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Input processing time
'Thinking' time (reasoning models)
Outputting time
Reasoning models are indicated by a lightbulb icon.

Seconds to receive a 500 token response. Key components:

  • Input time: Time to receive the first response token
  • Thinking time (only for reasoning models): Time reasoning models spend outputting tokens to reason prior to providing an answer. Amount of tokens based on the average reasoning tokens across a diverse set of 60 prompts (methodology details).
  • Answer time: Time to generate 500 output tokens, based on output speed

Figures represent performance of the model's first-party API (e.g. OpenAI for o1) or the median across providers where a first-party API is not available (e.g. Meta's Llama models).

Model Size (Open Weights Models Only)

Model Size: Total and Active Parameters

Comparison between total model parameters and parameters active during inference
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Active Parameters
Passive Parameters
Reasoning models are indicated by a lightbulb icon.

The total number of trainable weights and biases in the model, expressed in billions. These parameters are learned during training and determine the model's ability to process and generate responses.

The number of parameters actually executed during each inference forward pass, expressed in billions. For Mixture of Experts (MoE) models, a routing mechanism selects a subset of experts per token, resulting in fewer active than total parameters. Dense models use all parameters, so active equals total.

Frequently Asked Questions

Common questions about Claude 4.5 Sonnet (Reasoning)

Claude 4.5 Sonnet (Reasoning) was released on September 29, 2025.

Claude 4.5 Sonnet (Reasoning) was created by Anthropic.

Claude 4.5 Sonnet (Reasoning) scores 43 on the Artificial Analysis Intelligence Index, placing it well above average among other reasoning models in a similar price tier (median: 28).

Claude 4.5 Sonnet (Reasoning) generates output at 48.6 tokens per second (based on Anthropic's API), which is below average compared to other reasoning models in a similar price tier (median: 61.9 t/s).

Claude 4.5 Sonnet (Reasoning) has a time to first token (TTFT) of 13.27s (based on Anthropic's API), which is at the higher end compared to other reasoning models in a similar price tier (median: 2.70s).

Claude 4.5 Sonnet (Reasoning) costs $3.00 per 1M input tokens (somewhat higher than average, median: $1.60) and $15.00 per 1M output tokens (somewhat higher than average, median: $10.00), based on Anthropic's API.

Claude 4.5 Sonnet (Reasoning) costs $3.00 per 1M input tokens and $15.00 per 1M output tokens (based on Anthropic's API). For a blended rate (3:1 input to output ratio), this is $6.00 per 1M tokens. Pricing may vary by provider. Compare provider pricing

When evaluated on the Intelligence Index, Claude 4.5 Sonnet (Reasoning) generated 64M output tokens, which is at the higher end compared to other reasoning models in a similar price tier (median: 13M).

Yes, Claude 4.5 Sonnet (Reasoning) is a reasoning model. It uses extended thinking or chain-of-thought reasoning to work through complex problems before providing an answer.

Claude 4.5 Sonnet (Reasoning) supports text and image input.

Claude 4.5 Sonnet (Reasoning) supports text output.

Yes, Claude 4.5 Sonnet (Reasoning) supports image input and can analyze, describe, and answer questions about images.

Yes, Claude 4.5 Sonnet (Reasoning) is multimodal. It can process text and image input and generate text output.

Claude 4.5 Sonnet (Reasoning) has a context window of 1.0M tokens. This determines how much text and conversation history the model can process in a single request.

No, Claude 4.5 Sonnet (Reasoning) is proprietary. The model weights are not publicly available.

Claude 4.5 Sonnet (Reasoning) is a proprietary model and Anthropic has not disclosed the model size or parameter count.

Claude 4.5 Sonnet (Reasoning) achieves a score of 43 on the Artificial Analysis Intelligence Index. This composite benchmark evaluates models across reasoning, knowledge, mathematics, and coding.

Claude 4.5 Sonnet (Reasoning) has a knowledge cutoff of July 2025. The model's training data includes information up to this date.

Yes, Claude 4.5 Sonnet (Reasoning) is available via API through 4 providers. Compare API providers

Claude 4.5 Sonnet (Reasoning) is available through 4 API providers. Compare providers