GPT-5 vs Gemini 3 Flash for legal writing: which is better in 2026?
A head-to-head look at GPT-5 and Gemini 3 Flash 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, Gemini 3 Flash edges out GPT-5 on the contextWindow metric. Fastest mainstream model.
Side-by-side specs
| Spec | GPT-5 | Flash |
|---|---|---|
| Intelligence index | 78.4 | 63.2 |
| Coding index | 76.1 | 60.5 |
| Context window | 400K tokens | 1M tokens |
| Speed (tok/s) | 142 | 260 |
| Input $/M | $5.00 | $0.15 |
| Output $/M | $20.00 | $0.60 |
| Released | Aug 7, 2025 | Feb 12, 2026 |
How they handle legal writing
GPT-5: Top reasoning and math scores. The main caveat is more expensive than mid-tier models.
Gemini 3 Flash: Fastest mainstream model. The main caveat is weaker on nuanced reasoning.
Cost per 1,000 queries
Assuming 1,500 input and 800 output tokens per query:
- GPT-5: $23.50 per 1,000 queries
- Gemini 3 Flash: $0.70 per 1,000 queries
Verdict by sub-task
- Best raw quality on legal writing:
- Best price: Gemini 3 Flash
- Longest context: Gemini 3 Flash
- Fastest: Gemini 3 Flash
FAQ
Is GPT-5 better than Gemini 3 Flash for legal writing?
On May 2026 benchmarks (artificialanalysis.ai), Gemini 3 Flash ranks higher than GPT-5 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 or Gemini 3 Flash?
GPT-5 costs $5.00 input and $20.00 output per million tokens. Gemini 3 Flash costs $0.15 input and $0.60 output per million tokens.
Can I use both GPT-5 and Flash in one app?
Yes. Admix is a multi model AI chat aggregator that lets you run GPT-5 and Gemini 3 Flash side by side under one subscription.
Sources
Benchmarks from artificialanalysis.ai (May 2026).
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