GPT-5.5 vs Claude Opus 4.8: Same Input Price, Very Different Output Bills

Both GPT-5.5 and Claude Opus 4.8 come in at $5.00/1M input tokens, so the pricing duel really comes down to output: OpenAI charges $30.00/1M out, while Anthropic sits at $25.00/1M out. That 17% gap adds up fast on long-form tasks.

In practice, GPT-5.5 feels slightly snappier on structured outputs and tool-calling chains — it rarely fumbles JSON schemas or loses track of multi-step function calls. Claude Opus 4.8 punches harder on nuanced reasoning and longer context retention. Ask it to synthesize a 40-page doc and it stays coherent where GPT-5.5 occasionally drifts or repeats itself near the end.