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Claude Opus 5.5 vs Phi 4

Claude Opus 5.5 leads the LLM Stats Score 59.7 to 5.4. Phi 4 is 91.4x cheaper per token.

Anthropic · Microsoft · Updated for 2026

Which is better?

Claude Opus 5.5 leads the overall LLM Stats Score 59.7 to 5.4, ranking #1 overall.

On price, Phi 4 is roughly 91.4x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Claude Opus 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 Opus 5.5

  • overall performance matters — it scores 59.7 and ranks #1 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 91.4x cheaper per token
  • you need open weights you can self-host or fine-tune

At a glance

The differences that matter most.

Claude Opus 5.5
Anthropic
Phi 4
Microsoft
Core performance indexes
LLM Stats Score
59.7
#1
5.4
#302
Reasoning
57.8
#1
6.5
#293
Coding
51.7
#1
3.4
#223
Cost, coverage & limits
Benchmark wins
—
—
Input price
$4.00 / M
$0.07 / M
Output price
$20.00 / 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 Opus 5.5
Phi 4
Math
42.5#5
12.8#231
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

31 reported for Claude Opus 5.5 · 13 for Phi 4

No common benchmarks found

Claude Opus 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 Opus 5.5 ($4.00/1M tokens) is 57.1x more expensive than Phi 4 ($0.07/1M tokens).

For output processing, Claude Opus 5.5 ($20.00/1M tokens) is 142.9x more expensive than Phi 4 ($0.14/1M tokens).

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

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

Lowest available price from all providers
Wed Sep 23 2026 • llm-stats.com
Anthropic
Claude Opus 5.5
Input tokens$4.00
Output tokens$20.00
Best providerAnthropic
Microsoft
Phi 4
Input tokens$0.07
Output tokens$0.14
Best providerDeepinfra
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

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

Anthropic
Claude Opus 5.5
Input1,000,000 tokens
Output128,000 tokens
Microsoft
Phi 4
Input16,384 tokens
Output16,384 tokens
Wed Sep 23 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

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

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

Claude Opus 5.5

Text
Images
Audio
Video

Phi 4

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Opus 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 Opus 5.5

Proprietary

Closed source

Phi 4

MIT

Open weights

Release Timeline

When each model was launched

Claude Opus 5.5 was released on 2026-09-22, while Phi 4 was released on 2024-12-12.

Claude Opus 5.5 is 22 months newer than Phi 4.

Claude Opus 5.5

Sep 22, 2026

0 days ago

1.8yr newer
Phi 4

Dec 12, 2024

1.8 years ago

Knowledge Cutoff

When training data ends

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

Claude Opus 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 Opus 5.5

Jun 2026

2 yr newer
Phi 4

Jun 2024

Provider Availability

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

Claude Opus 5.5

anthropic logo
Anthropic
Input Price:Input: $4.00/1MOutput Price:Output: $20.00/1M

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?Start an Issue discussion→

Judge for yourself.

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

Claude Opus 5.5
✓ Preferred
Phi 4
Open in Playground

FAQ

Common questions about Claude Opus 5.5 vs Phi 4.

Which is better, Claude Opus 5.5 or Phi 4?

Claude Opus 5.5 leads the LLM Stats Score 59.7 to 5.4. Claude Opus 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 Opus 5.5 compare to Phi 4 in benchmarks?

Claude Opus 5.5 scores BenchCAD (with Python tool): 96.2%, Global-MMLU: 94.3%, SWE-bench Multilingual: 93.9%, MILU: 93.1%, ArXivMath: 91.2%. Phi 4 scores MMLU: 84.8%, HumanEval+: 82.8%, HumanEval: 82.6%, MGSM: 80.6%, MATH: 80.4%.

Is Claude Opus 5.5 cheaper than Phi 4?

Phi 4 is 57.1x cheaper for input tokens. Claude Opus 5.5 costs $4.00/M input and $20.00/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 Opus 5.5 and Phi 4?

Claude Opus 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 Opus 5.5 and Phi 4?

Key differences include LLM Stats Score (59.7 vs 5.4), context window (1.0M vs 16K), input pricing ($4.00 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 Opus 5.5 and Phi 4?

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

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