GPT-4o vs Claude 3.5 Sonnet (Thinking)

Compare GPT-4o and Claude 3.5 Sonnet (Thinking): 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 GPT-4o Claude 3.5 Sonnet (Thinking)
CategoryFrontierReasoning
Parameters~1T~500B
Context Window128K200K
Input Price$0.05/1M tokens$0.03/1M tokens
Output Price$0.15/1M tokens$0.15/1M tokens
Latency~400ms~600ms

Choose GPT-4o when:

  • ✓ Chart image analysis
  • ✓ Multimodal Q&A
  • ✓ Content generation
Key Strengths:

Multimodal, Fast for frontier, Strong reasoning

Choose Claude 3.5 Sonnet (Thinking) when:

  • ✓ Complex analysis
  • ✓ Multi-step logic
  • ✓ Verification tasks
Key Strengths:

Transparent thinking, Strong reasoning, Self-correction

Verdict: GPT-4o vs Claude 3.5 Sonnet (Thinking)

For cost efficiency, Claude 3.5 Sonnet (Thinking) wins at $0.03/1M input tokens. For speed, GPT-4o is faster at ~400ms. GPT-4o excels at Chart image analysis while Claude 3.5 Sonnet (Thinking) is better for Complex analysis. Both are available on XALEN through a single API — try them in the Playground to see which fits your workload.

Detailed Analysis

Pricing Comparison

GPT-4o costs $0.05/1M input tokens and $0.15/1M output tokens. Claude 3.5 Sonnet (Thinking) costs $0.03 input and $0.15 output. Claude 3.5 Sonnet (Thinking) is 1.7x cheaper on input tokens. XALEN offers batch processing at 50% discount on both models.

Performance & Context

GPT-4o has a 128K context window with ~400ms latency. Claude 3.5 Sonnet (Thinking) offers 200K context at ~600ms. Claude 3.5 Sonnet (Thinking) has the larger context window.

Best For

GPT-4o (Frontier) is optimized for: Chart image analysis, Multimodal Q&A, Content generation. Claude 3.5 Sonnet (Thinking) (Reasoning) works best for: Complex analysis, Multi-step logic, Verification tasks.

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 GPT-4o
response_a = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": "Your question here"}]
)

# Use Claude 3.5 Sonnet (Thinking)
response_b = client.chat.completions.create(
    model="claude-3-5-sonnet-thinking",
    messages=[{"role": "user", "content": "Your question here"}]
)

Start Building with XALEN

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Get API Key Try in Playground

Frequently Asked Questions

Which is better, GPT-4o or Claude 3.5 Sonnet (Thinking)?

GPT-4o (Frontier, ~1T) offers Multimodal. Claude 3.5 Sonnet (Thinking) (Reasoning, ~500B) offers Transparent thinking. Choose GPT-4o for Chart image analysis or Claude 3.5 Sonnet (Thinking) for Complex analysis.

How much does GPT-4o cost vs Claude 3.5 Sonnet (Thinking)?

GPT-4o: $0.05/1M input, $0.15/1M output. Claude 3.5 Sonnet (Thinking): $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 GPT-4o and Claude 3.5 Sonnet (Thinking) 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.