Claude Haiku 5.5 has an appealing price on paper, with a catch for anyone feeding it long prompts. Anthropic lists its starting API rates at $0.10 per million input tokens and $0.50 per million output tokens, matching OpenAI’s GPT-6 Luna. Cross 100,000 input tokens, though, and Haiku’s rates jump fivefold.
That makes prompt length central to the buying decision. Haiku deserves a look for shorter workloads, particularly if you already pay for Claude and can use the monthly API credits. For longer requests, Luna’s published rates are more attractive.
The price changes after 100,000 tokens
The companies’ listed standard token rates break down like this. All prices are in US dollars per million tokens; caching and discounted processing options are excluded.
| Model | Input length per request | Input price | Output price |
|---|---|---|---|
| Claude Haiku 5.5 | Up to 100,000 tokens | $0.10 | $0.50 |
| Claude Haiku 5.5 | Over 100,000 tokens | $0.50 | $2.50 |
| GPT-6 Luna | Up to 272,000 tokens | $0.10 | $0.50 |
| GPT-6 Luna | Over 272,000 tokens | $0.20 | $0.75 |
Luna keeps its base rates through a substantially larger input allowance, and its higher tier remains below Haiku’s. Those rates favor Luna for long inputs. Answer quality, output length and the work required to complete a task still determine overall value.
There’s another wrinkle in the AI API pricing comparison: token counts. Anthropic estimates that Haiku 5.5’s tokenizer produces roughly 30% more tokens from the same text than Haiku 4.5’s, with the exact increase depending on the content. Recount existing prompts before budgeting a migration, especially near the 100,000-token boundary.
Reasoning effort needs its own budget
Anthropic offers five effort settings, from low through max, with medium as the default. Higher effort gives the model more room to work through a task, but the cheapest token rate won’t necessarily produce the cheapest completed job.
Thinking is enabled by default. It can be disabled at low, medium or high effort; xhigh and max require adaptive thinking. That distinction matters for applications where response time is part of the product.
Start with medium and compare results on representative tasks before raising the setting. An improvement needs to justify both the extra tokens and the wait. A striking drawing or a strong benchmark result alone cannot establish that tradeoff for your workload.
Monthly credits improve the subscriber equation
Anthropic’s monthly Claude Platform credit allowances are:
- Max 5x: $100 per month.
- Max 20x: $200 per month.
- Team: a shared pool based on seats, capped at $500 per month.
Eligible subscribers claim the credits by linking a Claude Console organization through their plan’s billing settings. New subscribers must have held an eligible plan for seven days. Unused credits expire at the end of each billing cycle.
For someone already paying for Max or Team, this makes API experimentation easier to justify. The practical value depends on how much of the allowance you actually use.
Check Claude API billing before treating the allowance as a spending cap. Purchased credits can keep requests running after the monthly credit is exhausted, and auto-reload can buy more. Prepaid requests stop when the available balance runs out without replenishment; invoiced organizations continue under their billing arrangement.
Anthropic also announced a 50% reduction in Sonnet 5.5 cache-read pricing. That is a separate saving for workflows that reuse cached input.
Verdict: shortlist Haiku for shorter requests
Haiku 5.5 looks worth evaluating when prompts stay within its lower pricing tier and existing subscription credits can cover some usage. Its appeal weakens once requests cross that threshold.
For long prompts, start the cost comparison with Luna. For either model, make the final choice using your own token counts, response times and acceptable answers. The published rates establish the starting point; the cost of finishing your actual work decides the value.