Best LLMs for Email Writing (2026)
Large language models optimized for professional email drafting, cold outreach, reply generation, and inbox summarization — balancing tone, brevity, and personalization.
Why Claude Haiku 4 is Best for Email Writing
Claude Haiku 4 ranks highest for this use case based on Arena ELO score, benchmark performance, and capability coverage. It provides the best combination of quality, speed, and reliability for these specific tasks.
Cost Estimate
For a typical workload (~50M tokens/month, 60% input / 40% output), the cheapest qualifying model (Gemini 2.0 Flash) costs approximately $11.00/month. The most capable model may cost more but delivers higher quality results.
Price vs Quality for Email Writing
Top 5 Models Compared
| Rank | Model | Provider | Input $/M | Output $/M | Arena ELO | Speed (tok/s) |
|---|---|---|---|---|---|---|
| #1 | Claude Haiku 4 | Anthropic | $1.00 | $5.00 | 1415 | 130 |
| #2 | GPT-4o Mini | OpenAI | $0.150 | $0.600 | 1098 | 120 |
| #3 | GPT-4 1.5-mini | OpenAI | $0.400 | $1.60 | 1180 | 120 |
| #4 | Claude Sonnet 4 | Anthropic | $2.00 | $10.00 | 1473 | 78 |
| #5 | Gemini 2.0 Flash | $0.100 | $0.400 | 1360 | 160 |
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