This is a value-versus-frontier matchup. Claude Sonnet 4.5 is Anthropic's workhorse: near-Opus quality at far lower cost and latency, and the default many developers run for clean, well-structured code and careful writing. It's the smart backbone for production assistants where cost-per-quality matters.
GPT-5.2 is the heavier hitter, with three tiers, stronger agentic tool orchestration, multimodal reasoning and polished document output. For the hardest tasks GPT-5.2 (especially the Thinking/Pro tiers) pulls ahead, but for the bulk of everyday coding and chat, Sonnet 4.5 delivers comparable results at a fraction of the price. A common pattern: Sonnet for volume, GPT-5.2 or Claude Opus for the toughest steps.
Which should you choose?
Claude Sonnet 4.5
Claude Sonnet 4.5 · 1M context
Pick it if
you want excellent coding and writing at a great price.
GPT-5.2
GPT-5.2 · 400K context
Pick it if
you need the strongest reasoning, multimodality and agentic tooling.
Claude Sonnet 4.5 wins on value and everyday coding; GPT-5.2 wins on top-end reasoning, multimodality and document work. For most teams, Sonnet is the default and GPT-5.2 the escalation.
Questions
Is Sonnet 4.5 good enough vs GPT-5.2?
For most coding and chat, yes. It offers near-frontier quality at much lower cost. Step up to GPT-5.2 (or Claude Opus) for the hardest tasks.
Which is cheaper?
Claude Sonnet 4.5 is significantly cheaper than GPT-5.2's higher tiers, making it ideal for high-volume use.