GPT-5 vs Claude Sonnet 4.5
Detailed pricing comparison and cost analysis.
Updated March 2026
Cost Simulator
| Feature | GPT-5 | Claude Sonnet 4.5 |
|---|---|---|
| Provider | OpenAI | Anthropic |
| Input Price (1M) | $1.25 | $3.00 |
| Output Price (1M) | $10.00 | $15.00 |
| Context Window | 400,000 | 200,000 |
Verdict
GPT-5 costs $1.25 per 1M input tokens and $10.00 per 1M output tokens. Claude Sonnet 4.5 costs $3.00 per 1M input tokens and $15.00 per 1M output tokens. GPT-5 is 58% cheaper on input tokens than Claude Sonnet 4.5. For output tokens, GPT-5 is the more affordable option at $10.00/1M vs $15.00.
On context window, GPT-5 supports 400,000 tokens — meaning it can fit more conversation history, documents, or code in a single request. This matters for RAG pipelines, long document analysis, and agentic workflows where context builds up over many turns.
When to choose GPT-5
- ✓ You need the lowest input token cost ($ 1.25/1M)
- ✓ Your workload is output-heavy — GPT-5 generates text cheaper
- ✓ You need a larger context window (400,000 tokens)
- ✓ You are already integrated with OpenAI
When to choose Claude Sonnet 4.5
- ✓ You are already integrated with Anthropic
Use the calculator above to simulate your specific workload and find the exact break-even point. For most applications, the cheapest model is the one that minimises your total monthly bill given your input-to-output token ratio.