Claude Opus 4.5 vs Claude Sonnet 4.5

Compare Claude Opus 4.5 and Claude Sonnet 4.5: pricing, performance, context window, latency, and best use cases. Side-by-side comparison on XALEN.

Updated 2026-05-21 · By Abhishek Raj · Our methodology

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Feature Claude Opus 4.5 Claude Sonnet 4.5
CategoryFrontierFrontier
Parameters~2.5T~600B
Context Window200K200K
Input Price$0.15/1M tokens$0.03/1M tokens
Output Price$0.75/1M tokens$0.15/1M tokens
Latency~900ms~350ms

Choose Claude Opus 4.5 when:

  • ✓ Creative writing
  • ✓ Complex analysis
  • ✓ Research
Key Strengths:

Superior creativity, Nuanced reasoning, Complex analysis

Choose Claude Sonnet 4.5 when:

  • ✓ Code generation
  • ✓ Structured output
  • ✓ Automation
Key Strengths:

Strong coding, Better instruction following, Reliable

Verdict: Claude Opus 4.5 vs Claude Sonnet 4.5

For cost efficiency, Claude Sonnet 4.5 wins at $0.03/1M input tokens. For speed, Claude Sonnet 4.5 is faster at ~350ms. Claude Opus 4.5 excels at Creative writing while Claude Sonnet 4.5 is better for Code generation. Both are available on XALEN through a single API — try them in the Playground to see which fits your workload.

Detailed Analysis

Pricing Comparison

Claude Opus 4.5 costs $0.15/1M input tokens and $0.75/1M output tokens. Claude Sonnet 4.5 costs $0.03 input and $0.15 output. Claude Sonnet 4.5 is 5.0x cheaper on input tokens. XALEN offers batch processing at 50% discount on both models.

Performance & Context

Claude Opus 4.5 has a 200K context window with ~900ms latency. Claude Sonnet 4.5 offers 200K context at ~350ms. Both have identical context windows.

Best For

Claude Opus 4.5 (Frontier) is optimized for: Creative writing, Complex analysis, Research. Claude Sonnet 4.5 (Frontier) works best for: Code generation, Structured output, Automation.

Try Both on XALEN

Both models are available through XALEN's OpenAI-compatible API. Switch between them by changing the model parameter:

from xalen import XALEN

client = XALEN(api_key="xln_test_YOUR_KEY")

# Use Claude Opus 4.5
response_a = client.chat.completions.create(
    model="claude-opus-4-5",
    messages=[{"role": "user", "content": "Your question here"}]
)

# Use Claude Sonnet 4.5
response_b = client.chat.completions.create(
    model="claude-sonnet-4-5",
    messages=[{"role": "user", "content": "Your question here"}]
)

Start Building with XALEN

200+ AI models. One API. Pay-as-you-go.

Get API Key Try in Playground

Frequently Asked Questions

Which is better, Claude Opus 4.5 or Claude Sonnet 4.5?

Claude Opus 4.5 (Frontier, ~2.5T) offers Superior creativity. Claude Sonnet 4.5 (Frontier, ~600B) offers Strong coding. Choose Claude Opus 4.5 for Creative writing or Claude Sonnet 4.5 for Code generation.

How much does Claude Opus 4.5 cost vs Claude Sonnet 4.5?

Claude Opus 4.5: $0.15/1M input, $0.75/1M output. Claude Sonnet 4.5: $0.03/1M input, $0.15/1M output. Both available on XALEN with batch processing at 50% discount.

Can I use both models on XALEN?

Yes. XALEN provides 200+ models through a single OpenAI-compatible API. Switch between Claude Opus 4.5 and Claude Sonnet 4.5 by changing the model parameter. No code changes needed.

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Last updated: 2026-05-21. Pricing and specifications may change. Check pricing page for latest rates.