Claude Opus 4.8 vs GPT-5.4: flagship reasoning or workhorse value?
GPT-5.4 for most production workloads: it's cheaper and more than capable enough for RAG, chat, coding, and content generation. Claude Opus 4.8 for tasks where reasoning depth directly impacts business outcomes: legal analysis, scientific research, complex financial modeling, and multi-step autonomous agents where a wrong answer costs more than the API savings.
Anthropic's premium reasoning flagship against OpenAI's cost-effective workhorse.
Claude Opus 4.8 is Anthropic's latest flagship, built for deep reasoning, complex planning, and nuanced analysis. GPT-5.4 is OpenAI's workhorse model, balancing cost and capability for everyday production workloads. Opus 4.8 costs roughly 2x more per token. The question is whether your task genuinely needs Opus-level reasoning depth.
By TechCompare · Updated
Cost Comparison
Based on 100,000 input tokens (50% cached), 5,000 output tokens, and 100 requests.
Side-by-side specs
| Spec | Claude Opus 4.8 | GPT-5.4 |
|---|---|---|
| Input Cost (per M) | $5.00 | $2.50 (better on this spec) |
| Output Cost (per M) | $25.00 | $15.00 (better on this spec) |
| Cached Input (per M) | $0.50 | $0.25 (better on this spec) |
| Batch Discount | 50% | 50% |
How they differ
Claude Opus 4.8: $5/M input, $25/M output, 90% caching discount ($0.50/M cached), 50% batch discount. GPT-5.4: $2.50/M input, $15/M output, 90% caching discount ($0.25/M cached), 50% batch discount. For a typical 100K input + 10K output request, Opus 4.8 costs $0.75, GPT-5.4 costs $0.40. Over a million requests, that's $750K vs $400K — a $350K difference. Opus 4.8 leads on graduate-level reasoning, mathematical proofs, and multi-step agentic tasks. GPT-5.4 is competitive or better on general knowledge, coding, and instruction following at half the price.
Verdict
The cost ratio is a clean 2x across the board: $2.50/M input against $5.00 and $15.00/M output against $25.00. Cached input preserves the ratio at $0.25/M versus $0.50/M, and batch ties at 50% on both. A representative 100K input + 10K output call costs $0.40 on GPT-5.4 against $0.75 on Opus 4.8, which scales to roughly a $350K gap per million calls. Reach for Opus 4.8 only where its reasoning depth is doing decision work the cheaper model cannot do.
Which should you pick?
Choose Claude Opus 4.8
Tasks where reasoning depth directly impacts business outcomes: legal analysis, scientific research, complex financial modeling, and multi-step autonomous agents. The premium is justified when a wrong answer costs more than the API savings.
Choose GPT-5.4
Most production workloads: RAG, chat, coding, and content generation. GPT-5.4 is more than capable enough for these tasks at half the price.