Anthropic: Claude Sonnet 4.5

by Anthropic

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 improvements across system design, code security, and specification adherence. The model is designed for extended autonomous operation, maintaining task continuity across sessions and providing fact-based progress tracking. Sonnet 4.5 also introduces stronger agentic capabilities, including improved tool orchestration, speculative parallel execution, and more efficient context and memory management. With enhanced context tracking and awareness of token usage across tool calls, it is particularly well-suited for multi-context and long-running workflows. Use cases span software engineering, cybersecurity, financial analysis, research agents, and other domains requiring sustained reasoning and tool use.

Avg Score

82.7%

240 answers

Avg Latency

3.9s

16 runs

Pricing

$3.00

input

$15.00

output

per 1M tokens

Context

1000K

tokens

Alternatives

Models with similar or better quality but different tradeoffs

Same Quality, Cheaper

Models with similar or better performance at a lower cost per token.

Model	Cost
Google: Gemini 2.0 Flash	-98%
DeepSeek: DeepSeek V3.2	-96%
DeepSeek: DeepSeek V3 0324	-94%
MoonshotAI: Kimi K2 Thinking	-87%
Google: Gemini 2.5 Flash	-87%

Same Quality, Faster

Models with similar or better performance but lower latency.

Model	Latency
Google: Gemini 2.0 Flash	-71%
Google: Gemini 2.5 Flash	-64%
Google: Gemini 3 Flash Preview	-53%
OpenAI: GPT-5.2 Chat	-1%

Same Cost, Better

Models at a similar price point with higher benchmark scores.

Model	Score
Google: Gemini 3 Flash Preview	+7%
OpenAI: GPT-5.2	+5%
Anthropic: Claude Opus 4.5	+2%
OpenAI: GPT-5.2 Chat	+2%

Other Models from Anthropic

Compare performance with other models from the same creator

Model	Score	Latency	Cost/1M
Anthropic: Claude Opus 4.5	85.4%	4.0s	$15.00
Anthropic: Claude Haiku 4.5	78.8%	2.8s	$3.00
Anthropic: Claude 3.5 Haiku	77.7%	3.3s	$2.40
Anthropic: Claude 3 Haiku	75.2%	1.8s	$0.75
Anthropic: Claude Opus 4.1	—	—	$45.00
Anthropic: Claude Opus 4	—	—	$45.00
Anthropic: Claude Sonnet 4	—	—	$9.00
Anthropic: Claude 3.7 Sonnet	—	—	$9.00
Anthropic: Claude 3.7 Sonnet	—	—	$9.00
Anthropic: Claude 3.5 Haiku (2024-10-22)	—	—	$2.40
Anthropic: Claude 3.5 Sonnet	—	—	$18.00

Benchmark Performance

How this model performs across different benchmarks

Benchmark	Score	Rank
Math Bench: Subtraction (1-10)	100.0%	29 / 35
Enhancing FIDO UV Consistency with UXWG 2026 priority plan	100.0%	1 / 23
Math Bench: Arithmetic (1-100)	100.0%	5 / 35
Math Bench: Division (1-10)	100.0%	12 / 35
Venture Capital Terms Benchmark	100.0%	7 / 25
Math Bench: Addition (1-10)	100.0%	29 / 35
Motor production test	100.0%	19 / 36
Math Bench: Multiplication (1-10)	100.0%	29 / 35
Spatial Reasoning: Germany	96.9%	1 / 35
Math Bench: Arithmetic (1-1000)	95.0%	16 / 35
Character Frequency Bench	80.9%	22 / 35
Product Recommendations	80.0%	11 / 36
Karlsruhe Local Knowledge Benchmark	78.5%	15 / 35
Money Boy Cultural Literacy Test	51.4%	10 / 35
German Memelord Bench	34.8%	8 / 35
Karl Lorey knowlege	11.1%	8 / 36

Price vs Performance

Compare cost efficiency across all models

Current model

Other models

X-axis uses log scale for better visualization of price range

Score Over Time

Performance trends across all benchmark runs

Benchmark Activity

Number of benchmark runs over time

Quickstart

Get started with this model using OpenRouter

View on OpenRouter

import { OpenRouter } from "@openrouter/sdk";

const openrouter = new OpenRouter({
  apiKey: "<OPENROUTER_API_KEY>"
});

const completion = await openrouter.chat.completions.create({
  model: "anthropic/claude-sonnet-4.5",
  messages: [
    {
      role: "user",
      content: "Hello!"
    }
  ]
});

console.log(completion.choices[0].message.content);

Get your API key at openrouter.ai/keys