GPT-5 Mini vs Claude Haiku 4.5 for legal writing: which is better in 2026?
A head-to-head look at GPT-5 Mini and Claude Haiku 4.5 for legal writing. Benchmarks via artificialanalysis.ai, pricing as of May 2026. Compare AI models like these inside Admix.
Quick verdict
For legal writing in May 2026, Claude Haiku 4.5 edges out GPT-5 Mini on the contextWindow metric. Cheap Claude quality for everyday tasks.
Side-by-side specs
| Spec | GPT-5 Mini | Haiku |
|---|---|---|
| Intelligence index | 64.5 | 65.8 |
| Coding index | 61.0 | 66.2 |
| Context window | 200K tokens | 500K tokens |
| Speed (tok/s) | 220 | 205 |
| Input $/M | $0.25 | $0.80 |
| Output $/M | $1.00 | $4.00 |
| Released | Sep 10, 2025 | Mar 19, 2026 |
How they handle legal writing
GPT-5 Mini: Excellent quality-to-price ratio. The main caveat is behind flagships on hard reasoning.
Claude Haiku 4.5: Cheap Claude quality for everyday tasks. The main caveat is not as strong as opus on agentic coding.
Cost per 1,000 queries
Assuming 1,500 input and 800 output tokens per query:
- GPT-5 Mini: $1.18 per 1,000 queries
- Claude Haiku 4.5: $4.40 per 1,000 queries
Verdict by sub-task
- Best raw quality on legal writing:
- Best price: GPT-5 Mini
- Longest context: Claude Haiku 4.5
- Fastest: GPT-5 Mini
FAQ
Is GPT-5 Mini better than Claude Haiku 4.5 for legal writing?
On May 2026 benchmarks (artificialanalysis.ai), Claude Haiku 4.5 ranks higher than GPT-5 Mini for legal writing on the contextWindow metric. The gap is small enough that the choice often comes down to price, context length, and tone.
Which is cheaper, GPT-5 Mini or Claude Haiku 4.5?
GPT-5 Mini costs $0.25 input and $1.00 output per million tokens. Claude Haiku 4.5 costs $0.80 input and $4.00 output per million tokens.
Can I use both GPT-5 Mini and Haiku in one app?
Yes. Admix is a multi model AI chat aggregator that lets you run GPT-5 Mini and Claude Haiku 4.5 side by side under one subscription.
Sources
Benchmarks from artificialanalysis.ai (May 2026).
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