GPT-5.6 Luna vs Claude Haiku 4.5: API Cost Comparison (2026)
GPT-5.6 Luna or Claude Haiku 4.5? Instead of comparing list prices, we compute the same workload on both (prices verified 2026-09-17). Spoiler: GPT-5.6 Luna wins on raw cost in most scenarios — but "when to pick each" matters more than the winner. Compare them live in the calculator.
| Rate per 1M tokens | GPT-5.6 Luna | Claude Haiku 4.5 |
|---|---|---|
| Input | $0.20 | $1.00 |
| Cached input | $0.02 | $0.10 |
| Output | $1.20 | $5.00 |
Same workload, both models
| Monthly scenario | GPT-5.6 Luna | Claude Haiku 4.5 | Difference |
|---|---|---|---|
| Support chatbot (150k requests, 400 in / 300 out tokens) | $66.00 | $285.00 | 77% in favor of GPT-5.6 Luna |
| Document workflow (22k runs, 3,000 in / 400 out tokens) | $23.76 | $110.00 | 78% in favor of GPT-5.6 Luna |
| High-volume classifier (1M requests, 300 in / 10 out tokens) | $72.00 | $350.00 | 79% in favor of GPT-5.6 Luna |
Your token shape decides: input-heavy workloads (documents, RAG) amplify the input-rate gap; output-heavy ones (content generation) weigh the output rate. Run your exact mix in the calculator with both preselected.
When to pick each
- GPT-5.6 Luna — when per-token cost rules: high volume, verifiable tasks, tight budgets. It comes out 77–79% cheaper in these scenarios.
- Claude Haiku 4.5 — when the premium buys something you need (quality on your specific task, context, ecosystem). The only honest way to know: test your real case on both with a small sample.
- Both — the winning production pattern is often routing: easy requests to the cheap one, hard ones to the strong one.
Related guides: how AI API pricing works and how to reduce LLM costs.
Our read: Luna's published rates are five times lower on input and more than four times lower on output. Haiku must earn that premium through fewer failures, better instruction following or less human review in your actual support flow.
Use Luna for high-volume, verifiable internal work first. For customer-facing text, test both against tone, refusal and escalation criteria; the cheaper token bill is not cheaper if it creates review work.
Prices verified on 2026-09-17 against the provider's official pricing page. Estimates are for planning purposes only — always confirm current pricing with the provider.