Claude Haiku 4.5 vs GPT-4o-mini: which cheap fast model wins in 2026?
Claude Haiku 4.5 wins on instruction-following + tool use reliability. GPT-4o-mini wins on ecosystem and slightly lower cost. Pick Haiku for routing + structured output, GPT-4o-mini for OpenAI-native cheap tier.
At a glance
| Dimension | Claude Haiku 4.5 | GPT-4o-mini |
|---|---|---|
| Instruction following | Tightest in cheap tierWIN | Good |
| Tool use / function calling | Best in cheap tierWIN | Solid |
| Code quality | StrongWIN | Good |
| Multimodal | Image input | Image + audio inputWIN |
| Context window | 200KWIN | 128K |
| Speed | Fast | Fast |
| Price (input/output per 1M) | ~$0.80 / $4.00 | ~$0.15 / $0.60WIN |
| Ecosystem (SDKs, tools) | Anthropic + Bedrock + Vertex | OpenAI + AzureWIN |
| Best for | Routing, structured output, agent steps | OpenAI-native cheap tier |
Verdict
Claude Haiku 4.5 is the right cheap-tier pick for agent routing, structured output, and tool-use reliability — instruction-following holds up better at the low end. GPT-4o-mini is the right pick for OpenAI-native stacks and cost-sensitive workloads where pure ecosystem fit + price-per-token matter. Many production stacks use both — Haiku as the router or executor on tool-heavy steps, GPT-4o-mini for bulk classification + extraction.
When to pick which
Pick Claude Haiku 4.5
Agent routing, structured output, tool use, instruction-critical cheap-tier work.
Pick GPT-4o-mini
OpenAI-native, cheapest-per-token, multimodal (audio + image).
FAQ
Haiku or GPT-4o-mini for routing?
Haiku — best in cheap tier on tool use + instruction following.
Cheapest of the two?
GPT-4o-mini — materially cheaper per token in 2026.
Best for multimodal?
GPT-4o-mini — audio + image input native.
Last updated: 2026-06-01.