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

Anthropic
Google
Mistral
Openai

Top 5 Models Compared

RankModelProviderInput $/MOutput $/MArena ELOSpeed (tok/s)
#1Claude Haiku 4Anthropic$1.00$5.001220130
#2GPT-4o MiniOpenAI$0.150$0.6001220120
#3GPT-4.1 MiniOpenAI$0.400$1.601240115
#4Claude Sonnet 4Anthropic$3.00$15.00128078
#5Gemini 2.0 FlashGoogle$0.100$0.4001260160
#1Claude Haiku 4
Anthropic
ELO 1220
Input

$1.00/M

Output

$5.00/M

VisionJSON ModeFunctionsMultimodal
#2GPT-4o Mini
OpenAI
ELO 1220
Input

$0.150/M

Output

$0.600/M

VisionJSON ModeFunctionsMultimodal
#3GPT-4.1 Mini
OpenAI
ELO 1240
Input

$0.400/M

Output

$1.60/M

VisionJSON ModeFunctionsMultimodal
#4Claude Sonnet 4
Anthropic
ELO 1280
Input

$3.00/M

Output

$15.00/M

VisionJSON ModeFunctionsMultimodal
#5Gemini 2.0 Flash
Google
ELO 1260
Input

$0.100/M

Output

$0.400/M

VisionJSON ModeFunctionsMultimodalCode Exec
#6Mistral Small
Mistral
ELO 1185
Input

$0.150/M

Output

$0.600/M

JSON ModeFunctions

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