Model Comparison

Claude Sonnet 4.5 vs Gemini 2.5 Flash

Claude Sonnet 4.5 significantly outperforms across most benchmarks. Gemini 2.5 Flash is 7.1x cheaper per token.

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Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

Claude Sonnet 4.5 outperforms in 2 benchmarks (AIME 2025, GPQA), while Gemini 2.5 Flash is better at 0 benchmarks.

Claude Sonnet 4.5 significantly outperforms across most benchmarks.

Wed Apr 29 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Gemini 2.5 Flash costs less

For input processing, Claude Sonnet 4.5 ($3.00/1M tokens) is 10.0x more expensive than Gemini 2.5 Flash ($0.30/1M tokens).

For output processing, Claude Sonnet 4.5 ($15.00/1M tokens) is 6.0x more expensive than Gemini 2.5 Flash ($2.50/1M tokens).

In conclusion, Claude Sonnet 4.5 is more expensive than Gemini 2.5 Flash.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Wed Apr 29 2026 • llm-stats.com
Anthropic
Claude Sonnet 4.5
Input tokens$3.00
Output tokens$15.00
Best providerAnthropic
Google
Gemini 2.5 Flash
Input tokens$0.30
Output tokens$2.50
Best providerGoogle
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Context Window

Maximum input and output token capacity

Gemini 2.5 Flash accepts 1,048,576 input tokens compared to Claude Sonnet 4.5's 200,000 tokens. Gemini 2.5 Flash can generate longer responses up to 65,536 tokens, while Claude Sonnet 4.5 is limited to 64,000 tokens.

Anthropic
Claude Sonnet 4.5
Input200,000 tokens
Output64,000 tokens
Google
Gemini 2.5 Flash
Input1,048,576 tokens
Output65,536 tokens
Wed Apr 29 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Claude Sonnet 4.5 and Gemini 2.5 Flash support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

Claude Sonnet 4.5

Text
Images
Audio
Video

Gemini 2.5 Flash

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

Claude Sonnet 4.5

Proprietary

Closed source

Gemini 2.5 Flash

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Sonnet 4.5 was released on 2025-09-29, while Gemini 2.5 Flash was released on 2025-05-20.

Claude Sonnet 4.5 is 4 months newer than Gemini 2.5 Flash.

Claude Sonnet 4.5

Sep 29, 2025

7 months ago

4mo newer
Gemini 2.5 Flash

May 20, 2025

11 months ago

Knowledge Cutoff

When training data ends

Both models have the same knowledge cutoff date of 2025-01-31.

They should have similar awareness of historical events and information up to this date.

Claude Sonnet 4.5

Jan 2025

Gemini 2.5 Flash

Jan 2025

Provider Availability

Claude Sonnet 4.5 is available from Anthropic. Gemini 2.5 Flash is available from Google.

Claude Sonnet 4.5

anthropic logo
Anthropic
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M

Gemini 2.5 Flash

google logo
Google
Input Price:Input: $0.30/1MOutput Price:Output: $2.50/1M
* Prices shown are per million tokens

Outputs Comparison

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Key Takeaways

Anthropic
Higher AIME 2025 score (87.0% vs 72.0%)
Higher GPQA score (83.4% vs 82.8%)
Google
Larger context window (1,048,576 tokens)
Less expensive input tokens
Less expensive output tokens
AnthropicClaude Sonnet 4.5
GoogleGemini 2.5 Flash
Compare in Playground

Detailed Comparison

AI Model Comparison Table
Feature
Anthropic
Claude Sonnet 4.5
Google
Gemini 2.5 Flash

FAQ

Common questions about Claude Sonnet 4.5 vs Gemini 2.5 Flash

Claude Sonnet 4.5 significantly outperforms across most benchmarks. Claude Sonnet 4.5 is made by Anthropic and Gemini 2.5 Flash is made by Google. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.
Claude Sonnet 4.5 scores MMMLU: 89.1%, AIME 2025: 87.0%, TAU-bench Retail: 86.2%, GPQA: 83.4%, MMMUval: 77.8%. Gemini 2.5 Flash scores Global-MMLU-Lite: 88.4%, AIME 2024: 88.0%, FACTS Grounding: 85.3%, GPQA: 82.8%, MMMU: 79.7%.
Gemini 2.5 Flash is 10.0x cheaper for input tokens. Claude Sonnet 4.5 costs $3.00/M input and $15.00/M output via anthropic. Gemini 2.5 Flash costs $0.30/M input and $2.50/M output via google.
Claude Sonnet 4.5 supports 200K tokens and Gemini 2.5 Flash supports 1.0M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.
Key differences include context window (200K vs 1.0M), input pricing ($3.00 vs $0.30/M). See the full comparison above for benchmark-by-benchmark results.
Claude Sonnet 4.5 is developed by Anthropic and Gemini 2.5 Flash is developed by Google.