Capability · Comparison
Claude Haiku 4.5 vs GPT-5 nano
A head-to-head of the two cheapest production-grade models from the big two labs: Claude Haiku 4.5 and GPT-5 nano. These power the bulk of real-world LLM volume — classification, extraction, routing, and autocomplete. Haiku leans quality; nano leans throughput and price. Both beat mid-tier models from 18 months ago.
Side-by-side
| Criterion | Claude Haiku 4.5 | GPT-5 nano |
|---|---|---|
| Context window | 200,000 tokens | 400,000 tokens |
| Pricing ($/M input) As of 2026-04. | $1 | $0.05 |
| Pricing ($/M output) As of 2026-04. | $5 | $0.40 |
| Tool-call reliability | Strong | OK, weaker on multi-step |
| Coding | Meaningfully better than nano | Basic |
| Latency (short prompts) | Fast | Very fast |
| Multimodal | Text, vision | Text, vision |
| Typical use | Agent sub-tasks, light coding, triage | Classification, extraction, autocomplete |
| Availability | Anthropic API, Bedrock, Vertex | Responses API, Azure OpenAI |
Verdict
At small-model tier, quality compounds over volume. Haiku 4.5 is the better choice when the small model is part of an agent loop — tool-call reliability stops silent failures and saves token spend. GPT-5 nano wins on raw cost and latency and is the right pick for stateless, high-QPS NLP. Many teams end up with nano in front and Haiku behind for anything structured.
When to choose each
Choose Claude Haiku 4.5 if…
- The small model is a sub-agent in a larger Claude pipeline.
- Tool calls and structured output quality matter.
- You need better coding than nano can deliver at this tier.
- You're already on Anthropic infra and want one vendor.
Choose GPT-5 nano if…
- You're at high QPS and every fraction of a cent matters.
- The task is extraction, classification, or routing.
- You need the lowest latency at this tier.
- You're already on OpenAI or Azure OpenAI.
Frequently asked questions
Is Claude Haiku 4.5 worth the premium over GPT-5 nano?
If your small model is doing tool calls or agentic sub-tasks, yes — the reliability gap usually pays for itself. For pure extraction or classification, nano is the smarter buy.
Can GPT-5 nano handle coding?
Basic snippets and completions, yes. For anything structural — multi-file edits, refactors, or agentic coding — you want Haiku 4.5 or higher.
What about Gemini Flash at this tier?
Gemini 2.5 Flash competes directly, often beating both on price-per-quality for vision-heavy tasks. Pick by your actual workload.
Sources
- Anthropic — Models overview — accessed 2026-04-20
- OpenAI — Models — accessed 2026-04-20