About Claude Opus 4.8
Claude Opus 4.8 was the top of Anthropic's generally available lineup immediately before the Claude 5 generation, and it remains available as a legacy model with the same million-token context, large output ceiling and adaptive thinking as its successor. Distinctively, its effort parameter defaults to the highest setting on every surface, not just the API.
It also plays a quiet ongoing role in the current lineup: Anthropic's launch material describes Fable's safety system as falling back to Opus 4.8 for sensitive topics. For teams with validated Opus 4.8 behaviour, Anthropic maintains a documented migration path to Opus 5.
Opus 4.8 and Opus 5 share identical list pricing, which makes the decision unusually simple: there is no cost argument in either direction, only a capability and freshness one, and Anthropic's own guidance points migration at the newer model. The always-high effort default matters here more than anywhere — every request leans toward maximum deliberation unless you dial it down, and that deliberation bills as output tokens. Standard family mechanics apply: deep cache-read discounts, cache-write premium, half-price batch. Treat it as a continuity option for validated integrations rather than a starting point for new work.
Frequently asked questions
How much does the Claude Opus 4.8 API cost?
Claude Opus 4.8 costs $5 per million input tokens and $25 per million output tokens, with cached input at $0.5 per million (90% off).
How much does a typical chat message cost with Claude Opus 4.8?
A short chat message (about 500 input and 250 output tokens) costs roughly $0.0088 with Claude Opus 4.8. At 1,000 such requests a day, that is about $262.50 per month.
Is Claude Opus 4.8 cheap compared to similar models?
Claude Opus 4.8 has the #26 cheapest input rate of the 29 models we track. On a mixed workload (10K input / 2K output), it costs $0.100 per request, versus $0.045 for GPT-4o.
What does Claude Opus 4.8 cost per 1,000 tokens?
Per 1,000 tokens, Claude Opus 4.8 costs $0.0050 for input and $0.0250 for output, or $0.00050 for cached input. Providers quote rates per million tokens ($5/M in, $25/M out here), so divide by a thousand for the per-1K figure older pricing pages used.
How large a prompt can Claude Opus 4.8 take?
Claude Opus 4.8 accepts up to 977K tokens of input context and can generate up to 125K tokens of output per request. At its input rate, filling the entire 977K-token window costs about $5.00 per request before any output.
Related
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All Anthropic model costs: Claude Fable 5.1 · Claude Fable 5 · Claude Opus 5 · Claude Sonnet 5 · Claude Haiku 4.5
Last updated 2026-09-03. Prices verified against Anthropic's official pricing page; see the methodology.