Claude Opus 4 vs. GPT-5.5: What You're Actually Paying

If you're eyeing the top-tier models right now, the two big contenders are Anthropic's Claude Opus 4 and OpenAI's GPT-5.5 — and the price gap is real enough to matter.

Claude Opus 4 (all three variants: -6, -7, and -8) runs $5.00 per million tokens in and $25.00 out. GPT-5.5 matches the input price at $5.00 in, but jumps to $30.00 out. That's a 20% premium on output with GPT-5.5 — and in most real workloads, output is where your bill actually lives.

Say you're pushing 10 million output tokens a month. That's $250 with Opus 4, or $300 with GPT-5.5. Not catastrophic, but it adds up, especially if you're scaling.

Neither of these is a budget pick. If cost is the priority, deepseek-v4-flash at $0.14 in / $0.28 out is a completely different world — roughly 100x cheaper on output. Kimi-k2.5 and deepseek-v4-pro sit in the middle if you want something capable without flagship pricing.

But if you need the heaviest-duty models and you're choosing between Opus 4 and GPT-5.5, Anthropic's got the friendlier output rate right now. Simple as that.