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Open Source vs Proprietary LLMs: Complete Guide 2026

Compare open-source LLMs (Llama 3, Mistral, DeepSeek) with proprietary models (GPT-5, Claude, Gemini). Cost, performance, privacy, and deployment options.

Last updated: February 2026

Pricing Comparison

Model Provider Input $/1M Output $/1M Context Max Output
Llama 3.3 70B Meta (Open Weight) $0.88 $0.88 128K 4K
Mistral Large 3 Mistral AI $2 $6 128K 8K
GPT-5 OpenAI (Proprietary) $1.25 $10 400K 128K
Claude Sonnet 4.5 Anthropic (Proprietary) $3 $15 200K 64K

Detailed Comparison

Llama 3.3 70B

Meta (Open Weight)

$0.88 / $0.88

per 1M tokens

Strengths

  • + Open weights (Llama Community License)
  • + Self-hostable (70B fits on 2x A100)
  • + Competitive with proprietary mid-tier

Best For

Self-hosting, data privacy requirements

Context Window

128K

Max Output

4K

Mistral Large 3

Mistral AI

$2 / $6

per 1M tokens

Strengths

  • + Strong multilingual support
  • + European data sovereignty option
  • + Good balance of open and capable

Best For

Multilingual applications, EU compliance

Context Window

128K

Max Output

8K

GPT-5

OpenAI (Proprietary)

$1.25 / $10

per 1M tokens

Strengths

  • + State-of-the-art quality
  • + Full multi-modal support
  • + Enterprise-grade reliability

Best For

Maximum quality tasks, enterprise production

Context Window

400K

Max Output

128K

Claude Sonnet 4.5

Anthropic (Proprietary)

$3 / $15

per 1M tokens

Strengths

  • + Excellent coding performance
  • + Strong instruction following
  • + Extended thinking for complex tasks

Best For

Coding, analysis, production workloads

Context Window

200K

Max Output

64K

Verdict

Open-weight LLMs (Llama, Mistral, DeepSeek) offer cheaper API pricing and self-hosting capability — ideal for privacy-sensitive or budget-constrained projects. Proprietary models (GPT-5, Claude) deliver broader capabilities and enterprise support. GPT-5 at $1.25/$10 is now competitively priced against open-weight alternatives. Use our VRAM Calculator to check if you can run open-source models on your hardware.

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FAQ

Which is cheaper, Llama 3.3 70B or Mistral Large 3?

Llama 3.3 70B costs $0.88/$0.88 per million tokens (input/output), while Mistral Large 3 costs $2/$6. Llama 3.3 70B is cheaper for input.

Which has a larger context window?

Llama 3.3 70B supports 128K context, while Mistral Large 3 supports 128K. Larger context windows allow processing more text in a single request.

Which should I choose for my project?

Open-weight LLMs (Llama, Mistral, DeepSeek) offer cheaper API pricing and self-hosting capability — ideal for privacy-sensitive or budget-constrained projects. Proprietary models (GPT-5, Claude) deliver broader capabilities and enterprise support. GPT-5 at $1.25/$10 is now competitively priced against open-weight alternatives. Use our VRAM Calculator to check if you can run open-source models on your hardware.