Choosing between Claude Opus 4.8 (Anthropic) and GPT-5.4 (OpenAI)? This is a side-by-side of their API pricing, context windows, and real cost on a sample workload — so you can pick on the numbers, not the marketing.
Claude Opus 4.8 vs GPT-5.4: pricing & specs
| Claude Opus 4.8 | GPT-5.4 | |
|---|---|---|
| Vendor | Anthropic | OpenAI |
| Input / 1M tokens | $5.00 | $2.50 |
| Output / 1M tokens | $25.00 | $15.00 |
| Cached input / 1M | $0.50 | $0.25 |
| Context window | 200K tokens | 400K tokens |
Cost example: 1M input + 1M output tokens
For a workload of 1M input plus 1M output tokens, Claude Opus 4.8 costs $30.00 and GPT-5.4 costs $17.50 — GPT-5.4 is about 42% cheaper on this mix. Your real ratio of input to output tokens shifts the math; plug in your own numbers with the token cost calculator.
Which should you choose?
- Lower cost: GPT-5.4 is cheaper on output tokens ($15.00 vs $25.00 / 1M), which usually dominates spend on generation-heavy workloads.
- Larger context window: GPT-5.4 fits more in one prompt (400K tokens) — better for long documents or big RAG context.
- Ecosystem: pick the provider whose SDK, rate limits, and tooling fit your stack — see Anthropic rate limits and OpenAI rate limits.
Full specs: Claude Opus 4.8 · GPT-5.4. Thinking of switching providers? See the migration guides.
Prices as of June 2026 and change often — verify before relying on them.