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Claude Sonnet 5.5 vs Phi 4

Claude Sonnet 5.5 leads the LLM Stats Score 58.0 to 5.4. Phi 4 is 45.7x cheaper per token.

Anthropic · Microsoft · Updated for 2026

Which is better?

Claude Sonnet 5.5 leads the overall LLM Stats Score 58.0 to 5.4, ranking #3 overall.

On price, Phi 4 is roughly 45.7x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Claude Sonnet 5.5 also accepts a larger context window (1,000,000 input tokens), making it the stronger choice for long documents and large codebases.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose Claude Sonnet 5.5

  • overall performance matters — it scores 58.0 and ranks #3 on LLM Stats
  • your work emphasizes reasoning and coding — it leads those capability indexes
  • you process long inputs — it offers a 1,000,000 token context window
  • you want the most recent training data — it shipped Sep 2026

Choose Phi 4

  • cost matters — it's about 45.7x cheaper per token
  • you need open weights you can self-host or fine-tune

At a glance

The differences that matter most.

Claude Sonnet 5.5
Anthropic
Phi 4
Microsoft
Core performance indexes
LLM Stats Score
58.0
#3
5.4
#304
Reasoning
56.6
#3
6.5
#295
Coding
48.8
#2
3.4
#225
Cost, coverage & limits
Benchmark wins
—
—
Input price
$2.00 / M
$0.07 / M
Output price
$10.00 / M
$0.14 / M
Context window
1,000,000
16,384

Capability indexes

Additional strengths measured across groups of related public benchmarks

1 shared
Index
Claude Sonnet 5.5
Phi 4
Math
36.9#34
12.8#232
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

47 reported for Claude Sonnet 5.5 · 13 for Phi 4

No common benchmarks found

Claude Sonnet 5.5 and Phi 4don't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

Phi 4 costs less

For input processing, Claude Sonnet 5.5 ($2.00/1M tokens) is 28.6x more expensive than Phi 4 ($0.07/1M tokens).

For output processing, Claude Sonnet 5.5 ($10.00/1M tokens) is 71.4x more expensive than Phi 4 ($0.14/1M tokens).

In conclusion, Claude Sonnet 5.5 is more expensive than Phi 4.*

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

Lowest available price from all providers
Sat Oct 03 2026 • llm-stats.com
Anthropic
Claude Sonnet 5.5
Input tokens$2.00
Output tokens$10.00
Best providerAnthropic
Microsoft
Phi 4
Input tokens$0.07
Output tokens$0.14
Best providerDeepinfra
Notice missing or incorrect data?

Context Window

Maximum input and output token capacity

Claude Sonnet 5.5 accepts 1,000,000 input tokens compared to Phi 4's 16,384 tokens. Claude Sonnet 5.5 can generate longer responses up to 128,000 tokens, while Phi 4 is limited to 16,384 tokens.

Anthropic
Claude Sonnet 5.5
Input1,000,000 tokens
Output128,000 tokens
Microsoft
Phi 4
Input16,384 tokens
Output16,384 tokens
Sat Oct 03 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Claude Sonnet 5.5 supports multimodal inputs, whereas Phi 4 does not.

Claude Sonnet 5.5 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Claude Sonnet 5.5

Text
Images
Audio
Video

Phi 4

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Sonnet 5.5 is licensed under a proprietary license, while Phi 4 uses MIT.

License differences may affect how you can use these models in commercial or open-source projects.

Claude Sonnet 5.5

Proprietary

Closed source

Phi 4

MIT

Open weights

Release Timeline

When each model was launched

Claude Sonnet 5.5 was released on 2026-09-28, while Phi 4 was released on 2024-12-12.

Claude Sonnet 5.5 is 22 months newer than Phi 4.

Claude Sonnet 5.5

Sep 28, 2026

4 days ago

1.8yr newer
Phi 4

Dec 12, 2024

1.8 years ago

Knowledge Cutoff

When training data ends

Claude Sonnet 5.5 has a knowledge cutoff of 2026-06-01, while Phi 4 has a cutoff of 2024-06-01.

Claude Sonnet 5.5 has more recent training data (up to 2026-06-01), making it potentially better informed about events through that date compared to Phi 4 (2024-06-01).

Claude Sonnet 5.5

Jun 2026

2 yr newer
Phi 4

Jun 2024

Provider Availability

Claude Sonnet 5.5 is available from Anthropic. Phi 4 is available from DeepInfra.

Claude Sonnet 5.5

anthropic logo
Anthropic
Input Price:Input: $2.00/1MOutput Price:Output: $10.00/1M

Phi 4

deepinfra logo
Deepinfra
Input Price:Input: $0.07/1MOutput Price:Output: $0.14/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against Claude Sonnet 5.5 and Phi 4 side-by-side, then vote on the output you prefer.

Claude Sonnet 5.5
✓ Preferred
Phi 4
Open in Playground

FAQ

Common questions about Claude Sonnet 5.5 vs Phi 4.

Which is better, Claude Sonnet 5.5 or Phi 4?

Claude Sonnet 5.5 leads the LLM Stats Score 58.0 to 5.4. Claude Sonnet 5.5 is made by Anthropic and Phi 4 is made by Microsoft. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Claude Sonnet 5.5 compare to Phi 4 in benchmarks?

Claude Sonnet 5.5 scores BenchCAD (with Python tool): 96.3%, ArXivMath (with tools): 95.2%, Global-MMLU: 92.1%, MILU: 91.6%, SWE-bench Multilingual: 90.3%. Phi 4 scores MMLU: 84.8%, HumanEval+: 82.8%, HumanEval: 82.6%, MGSM: 80.6%, MATH: 80.4%.

Is Claude Sonnet 5.5 cheaper than Phi 4?

Phi 4 is 28.6x cheaper for input tokens. Claude Sonnet 5.5 costs $2.00/M input and $10.00/M output via anthropic. Phi 4 costs $0.07/M input and $0.14/M output via deepinfra.

What are the context window sizes for Claude Sonnet 5.5 and Phi 4?

Claude Sonnet 5.5 supports 1.0M tokens and Phi 4 supports 16K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Sonnet 5.5 and Phi 4?

Key differences include LLM Stats Score (58.0 vs 5.4), context window (1.0M vs 16K), input pricing ($2.00 vs $0.07/M), multimodal support (yes vs no), licensing (Proprietary vs MIT). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Sonnet 5.5 and Phi 4?

Claude Sonnet 5.5 is developed by Anthropic and Phi 4 is developed by Microsoft.

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