Claude Haiku 4.5 vs o3
Claude Haiku 4.5 (2025) and o3 (2025) are frontier reasoning models from Anthropic and OpenAI. Claude Haiku 4.5 ships a 200k-token context window, while o3 ships a 128K-token context window. On SWE-bench Verified, Claude Haiku 4.5 leads by 1.6 pts. On pricing, Claude Haiku 4.5 costs $0.8/1M input tokens versus $1/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Claude Haiku 4.5 is safer overall; choose o3 when coding workflow support matters.
Specs
| Released | 2025-10-01 | 2025-03-31 |
| Context window | 200k | 128K |
| Parameters | — | — |
| Architecture | decoder only | decoder only |
| License | Proprietary | Unknown |
| Knowledge cutoff | 2025-02 | - |
Pricing and availability
| Claude Haiku 4.5 | o3 | |
|---|---|---|
| Input price | $0.8/1M tokens | $1/1M tokens |
| Output price | $4/1M tokens | $4/1M tokens |
| Providers |
Capabilities
| Claude Haiku 4.5 | o3 | |
|---|---|---|
| Vision | ||
| Multimodal | ||
| Reasoning | ||
| Function calling | ||
| Tool use | ||
| Structured outputs | ||
| Code execution |
Benchmarks
| Benchmark | Claude Haiku 4.5 | o3 |
|---|---|---|
| SWE-bench Verified | 73.3 | 71.7 |
Deep dive
On shared benchmark coverage, SWE-bench Verified has Claude Haiku 4.5 at 73.3 and o3 at 71.7, with Claude Haiku 4.5 ahead by 1.6 points. The largest visible gap is 1.6 points on SWE-bench Verified, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint differs most on vision: Claude Haiku 4.5, multimodal input: Claude Haiku 4.5, reasoning mode: o3, function calling: Claude Haiku 4.5, and tool use: Claude Haiku 4.5. Both models share structured outputs and code execution, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, Claude Haiku 4.5 lists $0.8/1M input and $4/1M output tokens, while o3 lists $1/1M input and $4/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Claude Haiku 4.5 lower by about $0.14 per million blended tokens. Availability is 8 providers versus 3, so concentration risk also matters.
Choose Claude Haiku 4.5 when coding workflow support, larger context windows, and lower input-token cost are central to the workload. Choose o3 when coding workflow support are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, Claude Haiku 4.5 or o3?
Claude Haiku 4.5 supports 200k tokens, while o3 supports 128K tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Claude Haiku 4.5 or o3?
Claude Haiku 4.5 is cheaper on tracked token pricing. Claude Haiku 4.5 costs $0.8/1M input and $4/1M output tokens. o3 costs $1/1M input and $4/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude Haiku 4.5 or o3 open source?
Claude Haiku 4.5 is listed under Proprietary. o3 is listed under Unknown. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, Claude Haiku 4.5 or o3?
Claude Haiku 4.5 has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for multimodal input, Claude Haiku 4.5 or o3?
Claude Haiku 4.5 has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Claude Haiku 4.5 and o3?
Claude Haiku 4.5 is available on Microsoft Foundry, Anthropic, Snowflake Cortex, AWS Bedrock, and GCP Vertex AI. o3 is available on OpenAI API, OpenRouter, and OpenAI Batch API. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-04-24. Data sourced from public model cards and provider documentation.