Use case ยท checked October 12, 2026
Cheapest LLM API for document summarization
Claude Haiku 5.5 and GPT-6 Luna tie as the cheapest at $16.00 a month. Our assumption: 20,000 documents a month, about 6,000 tokens in (roughly 4,500 words) and a 400-token summary out.
| # | Model | Per month | Per request |
|---|---|---|---|
| 1 | Claude Haiku 5.5 | $16.00 | $0.00080 |
| 2 | GPT-6 Luna | $16.00 | $0.00080 |
| 3 | DeepSeek V4.1 Flash | $22.80 | $0.00114 |
| 4 | Gemini 3.1 Flash-Lite | $42.00 | $0.00210 |
| 5 | Gemini 3.5 Flash-Lite | $56.00 | $0.00280 |
| 6 | Mistral Large | $72.00 | $0.00360 |
| 7 | DeepSeek V4 Pro | $95.04 | $0.00475 |
| 8 | Gemini 3.8 Flash | $120 | $0.00600 |
| 9 | Gemini 3.6 Flash | $120 | $0.00600 |
| 10 | Grok Build 0.1 | $136 | $0.00680 |
| 11 | Claude Haiku 4.5 | $160 | $0.00800 |
| 12 | Grok 4.3 | $170 | $0.00850 |
| 13 | Grok 4.7 | $288 | $0.01440 |
| 14 | Claude Sonnet 5.5 | $320 | $0.01600 |
| 15 | GPT-6.1 Sol | $320 | $0.01600 |
| 16 | GPT-5.3 Codex | $322 | $0.01610 |
| 17 | Gemini 3.1 Pro | $336 | $0.01680 |
| 18 | Claude Opus 5.5 | $640 | $0.03200 |
| 19 | Claude Fable 5.1 | $1,600 | $0.08000 |
| 20 | GPT-6 Astra | $1,600 | $0.08000 |
Change the assumptions
Start from a use case
1,000 tokens is about 750 English words. Input includes your system prompt, chat history and any retrieved documents.
Claude Haiku 5.5
AnthropicCheapest
$16.00 /mo
GPT-6 Luna
OpenAICheapest
$16.00 /mo
DeepSeek V4.1 Flash
DeepSeek
$22.80 /mo
Gemini 3.1 Flash-Lite
Google
$42.00 /mo
Gemini 3.5 Flash-Lite
Google
$56.00 /mo
Mistral Large
Mistral
$72.00 /mo
DeepSeek V4 Pro
DeepSeek
$95.04 /mo
Gemini 3.8 Flash
Google
$120 /mo
Gemini 3.6 Flash
Google
$120 /mo
$136 /mo
Claude Haiku 4.5
Anthropic
$160 /mo
Grok 4.3
xAI
$170 /mo
Grok 4.7
xAI
$288 /mo
Claude Sonnet 5.5
Anthropic
$320 /mo
GPT-6.1 Sol
OpenAI
$320 /mo
GPT-5.3 Codex
OpenAI
$322 /mo
Gemini 3.1 Pro
Google
$336 /mo
Claude Opus 5.5
Anthropic
$640 /mo
Claude Fable 5.1
Anthropic
$1,600 /mo
GPT-6 Astra
OpenAI
$1,600 /mo