LLMCost

Anthropic: Claude Sonnet 4.5 vs OpenAI: GPT-5

On input price, OpenAI: GPT-5 is ~2.4× cheaper. Verified 2026-08-23.

MetricAnthropic: Claude Sonnet 4.5OpenAI: GPT-5
Input / 1M$3.00$1.25
Output / 1M$15.00$10.00
Cache read / 1M$0.300$0.125
Context window1M400K
Max output64K128K

Monthly cost by workload

WorkloadAnthropic: Claude Sonnet 4.5OpenAI: GPT-5Cheaper
Chatbot$84.00$50.00OpenAI: GPT-5
Coding agent$270.00$150.00OpenAI: GPT-5
RAG pipeline$585.00$300.00OpenAI: GPT-5

Full details: Anthropic: Claude Sonnet 4.5 pricing · OpenAI: GPT-5 pricing