Claude Haiku 5.5 matches GPT-6 Luna pricing but a stingier tokenizer hides a 1.25x cost hike

Simon Willison · rss · 2026-10-08

Anthropic released Claude Haiku 5.5, a fast, low-cost model priced identically to OpenAI's GPT-6 Luna ($0.10/$0.50 per million tokens) up to 100K tokens; beyond that it jumps 5x to $0.50/$2.50, while Luna only rises to $0.20/$0.75 after 272K — making Luna the better long-context deal.
Hidden cost: Haiku 5.5 uses a less generous tokenizer — the same long prompt consumes 1.25x more tokens than Haiku 4.5, per the author's Claude Token Counter tool, effectively raising prices further.
Hands-on testing via the llm-anthropic plugin: reasoning can no longer be disabled (defaults to medium). The pelican-on-a-bicycle test cost 0.0936 cents at low effort (7 seconds) and 3.38 cents at max effort (5m09s), with drawing quality far better than Haiku 4.5 a year ago.
Perks: Sonnet 5.5 cache reads halved in price; Max/Team subscribers get monthly API credits ($100 for Max 5x, $200 for Max 20x, up to $500 pooled for Team), roughly equal to the subscription fee, claimable in Billing settings, with optional auto-reload disabled to avoid surprise bills. OpenAI's Codex subscription API use still wins for heavy API users.

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