Claude Haiku 4.5 vs o3-mini: Detailed Comparison

Choosing between Claude Haiku 4.5 (Anthropic) and o3-mini (OpenAI) comes down to three things: per-token pricing, context window, and which capability matters most for your workload. Claude Haiku 4.5 costs $1.00/M input vs $1.10/M for o3-mini; context windows are 200K vs 200K tokens. Detailed breakdown below.

Side-by-side specs

SpecClaude Haiku 4.5o3-mini
ProviderAnthropicOpenAI
Released2025-10-012025-01-31
Input price $1.00/M $1.10/M
Output price $5.00/M $4.40/M
Cached input $0.1000/M $0.5500/M
Context window 200K 200K
Max output 16K 100K
Modalities text image text
Tokenizer claude-3 o200k_base

Capability matrix

CapabilityClaude Haiku 4.5o3-mini
function calling Yes Yes
json mode Yes Yes
vision Yes No
streaming Yes No
tool use Yes No
reasoning No Yes

Per-call cost on typical workloads

Workload (in/out tokens)Claude Haiku 4.5o3-miniCheaper by
Standard chat (1K / 500) $0.003500 $0.003300 o3-mini by $0.000200
RAG (4K / 500) $0.006500 $0.006600 Claude Haiku 4.5 by $0.000100
Long doc (20K / 1K) $0.025000 $0.026400 Claude Haiku 4.5 by $0.001400
Very long context (100K / 2K) $0.107500 $0.116600 Claude Haiku 4.5 by $0.009100

When to choose Claude Haiku 4.5 over o3-mini

  • Per-token input cost is 9% lower — meaningful for high-volume workloads.
  • Supports vision — o3-mini does not.
  • Supports streaming — o3-mini does not.
  • Supports tool use — o3-mini does not.

When to choose o3-mini over Claude Haiku 4.5

  • Supports reasoning — Claude Haiku 4.5 does not.

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