Model Comparison

Llama 3.1 8B Instruct vs Phi-3.5-mini-instructWhich is better in 2026?

Llama 3.1 8B Instruct has a slight edge in benchmark performance. Llama 3.1 8B Instruct is 3.3x cheaper per token.

Verdict: Llama 3.1 8B Instruct vs Phi-3.5-mini-instruct — which is better?

Llama 3.1 8B Instruct (by Meta) and Phi-3.5-mini-instruct (by Microsoft) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

Llama 3.1 8B Instruct outperforms in 3 benchmarks (HumanEval, MMLU, MMLU-Pro), while Phi-3.5-mini-instruct is better at 1 benchmark (ARC-C). Llama 3.1 8B Instruct has a slight edge in benchmark performance.

On price, Llama 3.1 8B Instruct is roughly 3.3x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Llama 3.1 8B Instruct also accepts a larger context window (131,072 input tokens), making it the stronger choice for long documents and large codebases.

Choose Llama 3.1 8B Instruct if…

  • you want the strongest raw capability — it leads on 3 of 5 shared benchmarks
  • cost matters — it's about 3.3x cheaper per token
  • you process long inputs — it offers a 131,072 token context window

Choose Phi-3.5-mini-instruct if…

  • you want the most recent training data — it shipped Aug 2024

Performance Benchmarks

Comparative analysis across standard metrics

5 benchmarks

Llama 3.1 8B Instruct outperforms in 3 benchmarks (HumanEval, MMLU, MMLU-Pro), while Phi-3.5-mini-instruct is better at 1 benchmark (ARC-C).

Llama 3.1 8B Instruct has a slight edge in benchmark performance.

Tue Jul 21 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Llama 3.1 8B Instruct costs less

For input processing, Llama 3.1 8B Instruct ($0.03/1M tokens) is 3.3x cheaper than Phi-3.5-mini-instruct ($0.10/1M tokens).

For output processing, Llama 3.1 8B Instruct ($0.03/1M tokens) is 3.3x cheaper than Phi-3.5-mini-instruct ($0.10/1M tokens).

In conclusion, Phi-3.5-mini-instruct is more expensive than Llama 3.1 8B Instruct.*

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

Lowest available price from all providers
Tue Jul 21 2026 • llm-stats.com
Meta
Llama 3.1 8B Instruct
Input tokens$0.03
Output tokens$0.03
Best providerLambda
Microsoft
Phi-3.5-mini-instruct
Input tokens$0.10
Output tokens$0.10
Best providerAzure
Notice missing or incorrect data?Start an Issue→

Model Size

Parameter count comparison

4.2B diff

Llama 3.1 8B Instruct has 4.2B more parameters than Phi-3.5-mini-instruct, making it 110.5% larger.

Meta
Llama 3.1 8B Instruct
8.0Bparameters
Microsoft
Phi-3.5-mini-instruct
3.8Bparameters
8.0B
Llama 3.1 8B Instruct
3.8B
Phi-3.5-mini-instruct

Context Window

Maximum input and output token capacity

Llama 3.1 8B Instruct accepts 131,072 input tokens compared to Phi-3.5-mini-instruct's 128,000 tokens. Llama 3.1 8B Instruct can generate longer responses up to 131,072 tokens, while Phi-3.5-mini-instruct is limited to 128,000 tokens.

Meta
Llama 3.1 8B Instruct
Input131,072 tokens
Output131,072 tokens
Microsoft
Phi-3.5-mini-instruct
Input128,000 tokens
Output128,000 tokens
Tue Jul 21 2026 • llm-stats.com

License

Usage and distribution terms

Llama 3.1 8B Instruct is licensed under Llama 3.1 Community License, while Phi-3.5-mini-instruct uses MIT.

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

Llama 3.1 8B Instruct

Llama 3.1 Community License

Open weights

Phi-3.5-mini-instruct

MIT

Open weights

Release Timeline

When each model was launched

Llama 3.1 8B Instruct was released on 2024-07-23, while Phi-3.5-mini-instruct was released on 2024-08-23.

Phi-3.5-mini-instruct is 1 month newer than Llama 3.1 8B Instruct.

Llama 3.1 8B Instruct

Jul 23, 2024

2.0 years ago

Phi-3.5-mini-instruct

Aug 23, 2024

1.9 years ago

1mo newer

Knowledge Cutoff

When training data ends

Llama 3.1 8B Instruct has a documented knowledge cutoff of 2023-12-31, while Phi-3.5-mini-instruct's cutoff date is not specified.

We can confirm Llama 3.1 8B Instruct's training data extends to 2023-12-31, but cannot make a direct comparison without Phi-3.5-mini-instruct's cutoff date.

Llama 3.1 8B Instruct

Dec 2023

Phi-3.5-mini-instruct

—

Provider Availability

Llama 3.1 8B Instruct is available from Lambda, DeepInfra, Groq, Sambanova, Cerebras, Hyperbolic, Together, Fireworks, Bedrock. Phi-3.5-mini-instruct is available from Azure.

Llama 3.1 8B Instruct

lambda logo
Lambda
Input Price:Input: $0.03/1MOutput Price:Output: $0.03/1M
deepinfra logo
Deepinfra
Input Price:Input: $0.05/1MOutput Price:Output: $0.05/1M
groq logo
Groq
Input Price:Input: $0.05/1MOutput Price:Output: $0.08/1M
sambanova logo
Sambanova
Input Price:Input: $0.10/1MOutput Price:Output: $0.20/1M
cerebras logo
Cerebras
Input Price:Input: $0.10/1MOutput Price:Output: $0.10/1M
hyperbolic logo
Hyperbolic
Input Price:Input: $0.10/1MOutput Price:Output: $0.10/1M
together logo
Together
Input Price:Input: $0.20/1MOutput Price:Output: $0.20/1M
fireworks logo
Fireworks
Input Price:Input: $0.20/1MOutput Price:Output: $0.20/1M
bedrock logo
AWS Bedrock
Input Price:Input: $0.22/1MOutput Price:Output: $0.22/1M

Phi-3.5-mini-instruct

azure logo
Azure
Input Price:Input: $0.10/1MOutput Price:Output: $0.10/1M
* Prices shown are per million tokens

Outputs Comparison

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Key Takeaways

Meta
Larger context window (131,072 tokens)
Less expensive input tokens
Less expensive output tokens
Higher HumanEval score (72.6% vs 62.8%)
Higher MMLU score (69.4% vs 69.0%)
Higher MMLU-Pro score (48.3% vs 47.4%)
Microsoft
Higher ARC-C score (84.6% vs 83.4%)

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Llama 3.1 8B Instruct and Phi-3.5-mini-instruct side-by-side, then vote on the output you prefer.

Llama 3.1 8B Instruct
✓ Preferred
Phi-3.5-mini-instruct
Open in Playground
AI Model Comparison Table
Feature
Meta
Llama 3.1 8B Instruct
Microsoft
Phi-3.5-mini-instruct

FAQ

Common questions about Llama 3.1 8B Instruct vs Phi-3.5-mini-instruct.

Which is better, Llama 3.1 8B Instruct or Phi-3.5-mini-instruct?

Llama 3.1 8B Instruct has a slight edge in benchmark performance. Llama 3.1 8B Instruct is made by Meta and Phi-3.5-mini-instruct is made by Microsoft. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Llama 3.1 8B Instruct compare to Phi-3.5-mini-instruct in benchmarks?

Llama 3.1 8B Instruct scores GSM-8K (CoT): 84.5%, ARC-C: 83.4%, API-Bank: 82.6%, IFEval: 80.4%, BFCL: 76.1%. Phi-3.5-mini-instruct scores GSM8k: 86.2%, ARC-C: 84.6%, RULER: 84.1%, PIQA: 81.0%, OpenBookQA: 79.2%.

Is Llama 3.1 8B Instruct cheaper than Phi-3.5-mini-instruct?

Llama 3.1 8B Instruct is 3.3x cheaper for input tokens. Llama 3.1 8B Instruct costs $0.03/M input and $0.03/M output via lambda. Phi-3.5-mini-instruct costs $0.10/M input and $0.10/M output via azure.

What are the context window sizes for Llama 3.1 8B Instruct and Phi-3.5-mini-instruct?

Llama 3.1 8B Instruct supports 131K tokens and Phi-3.5-mini-instruct supports 128K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Llama 3.1 8B Instruct and Phi-3.5-mini-instruct?

Key differences include context window (131K vs 128K), input pricing ($0.03 vs $0.10/M), licensing (Llama 3.1 Community License vs MIT). See the full comparison above for benchmark-by-benchmark results.

Who makes Llama 3.1 8B Instruct and Phi-3.5-mini-instruct?

Llama 3.1 8B Instruct is developed by Meta and Phi-3.5-mini-instruct is developed by Microsoft.

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