For anyone producing articles, newsletters and long copy. Claude Sonnet 5 writes the most natural long-form prose. GPT-5.5 holds a brief tightest but costs nearly three times as much per thousand words.
-
1
Claude Sonnet 5
The most natural long-form prose and the steadiest brand voice.
- 16 credits per 1k words
- Anthropic
- A higher rate
-
2
GPT-5.5
Holds a brief tightly. Best when the text should need little editing.
- 47 credits per 1k words
- OpenAI
- The most expensive in this group
-
3
Gemini 2.5 Pro
Very long context, so it writes from documents and research well.
- 16 credits per 1k words
- A higher rate than the light models
-
4
DeepSeek V4
Strong reasoning at a low rate. Good for analytical pieces.
- 2 credits per 1k words
- DeepSeek
- The style can read as technical
-
5
Kimi K2.5
Turns transcripts and research into a readable article.
- 6 credits per 1k words
- Moonshot AI
- A less familiar style
-
6
Claude Haiku 4.5
Fast and cheap for headlines, captions and variations.
- 8 credits per 1k words
- Anthropic
- Less suited to long pieces than Claude Sonnet 5
Brief first, price second
The ranking asks one question first: does the text do what the brief asked? Cost per thousand words breaks the ties. Claude Sonnet 5 leads with the most natural long-form prose and the steadiest brand voice. GPT-5.5 is second; it is the one to choose when text ships without editing. Gemini 2.5 Pro is third, with a very long context that lets it write from documents and research.
DeepSeek V4 is fourth for analytical pieces. Kimi K2.5 is fifth for turning transcripts into readable articles. Claude Haiku 4.5 closes the list for headlines, captions and variations.
When GPT-5.5 justifies 47 credits
Claude Sonnet 5 at 16 credits per thousand words should be your default for editorial articles and homepage copy. GPT-5.5 makes sense when the cost of editing is higher than the cost of the run. Think of client deliverables with a strict brief, regulated wording, or a long list of required points.
Working from a stack of documents, notes or an interview? Start with Gemini 2.5 Pro at 16 credits or Kimi K2.5 at 6. For twenty subject lines or ad variants, Claude Haiku 4.5 at 8 credits is quick and good enough.
Article costs side by side
An 800-word blog post is billed as a thousand words. It costs 16 credits on Claude Sonnet 5 or Gemini 2.5 Pro (about $0.17). The same post is 47 on GPT-5.5 (about $0.50), 8 on Claude Haiku 4.5 and 6 on Kimi K2.5. A two-thousand-word feature costs 32 credits on Claude Sonnet 5 (about $0.34). It is 94 on GPT-5.5 (about $1) and 12 on Kimi K2.5 (about $0.13).
Take the $9 pack of 750 credits. There, the difference between Claude Sonnet 5 and GPT-5.5 is the difference between many features and a few. DeepSeek V4 costs 2 credits per thousand words.
Testing Claude Sonnet 5 against GPT-5.5
Open the AI Article Generator with the Blog post preset. Write a brief with a word count and an audience. Add three points that must appear and one phrase that must not. For example: "For small café owners, explain how to price a seasonal drink. Mention cost per cup, a test week and a menu label. Do not use the word delicious." Run it on both models.
Check off the three points and look for the banned word. Then time your own edit. If Claude Sonnet 5 needs only a light pass, the cheaper run wins. If GPT-5.5 saves real editing on a client job, its rate pays for itself. For book-length drafts, both also run in AI Ebook Generator.
Where this list stops
Technical documentation has its own ranking, led by Qwen3 Coder. Character voice and roleplay are ranked separately too. This page also leaves out the cheapest open-weight models, which suit volume over quality. It does not judge facts in the output either. Every model here can be confidently wrong, so check claims before you publish.
More rankings
Questions about Best AI models for writing articles
What is the best AI model for writing articles?
Claude Sonnet 5 ranks first for natural long-form prose and a steady brand voice. It costs 16 credits per thousand words. Choose GPT-5.5 when the text must follow a strict brief without editing.
Which model should I use to write from research notes or transcripts?
Gemini 2.5 Pro has a very long context and works well from sources, at 16 credits per thousand words. Kimi K2.5 does a similar job for 6 credits, with a less familiar style.
What does a typical blog post cost with Claude Sonnet 5?
An 800-word post rounds up to a thousand words and costs 16 credits, about $0.17 at the largest pack. A two-thousand-word article costs 32 credits.
Can I use DeepSeek V4 for articles yet?
Yes. It is ranked for analytical pieces at 2 credits per thousand words. It runs in the AI Article Generator, AI Content Generator and AI Ebook Generator.
