claude-sonnet-4-5-20250929 vs gpt-5-chat Benchmark Comparison
Direct benchmark comparison between claude-sonnet-4-5-20250929 and gpt-5-chat based on LMArena Elo and the latest 2026 API pricing.
Direct Technical & Pricing Comparison
*These models represent the Pareto Frontier (optimal cost-to-performance).*
Comparison Summary: These models are highly competitive, with a negligible Elo gap of only 25 points. The choice between them should be driven by specific API features or provider preference. However, neither model is currently Pareto-optimal. Developers looking for peak efficiency should investigate gpt-5.2-chat-latest-20260210, which offers a superior benchmark-to-price ratio.