Claude Sonnet 4 ⌄
Claude Sonnet 4 ⌄
Claude Sonnet 4 has been retired. We recommend switching to Claude Sonnet 4.6 for the best experience.

Chat with Claude Sonnet 4

Powered by Anthropic.

Long-form writing Essays, articles, scripts
Read & summarize Paste any document
Translate & tone-match Across languages
Sensitive topic Thoughtful, balanced reply

Anthropic's strongest Sonnet model: exceptional at long-form writing, careful analysis, and following nuanced instructions.

Claude Sonnet 4 at a glance

ProviderAnthropic
Access on AskAI.freePremium model; the 7-day Pro trial unlocks access.
Best first testHigh-quality writing: essays, articles, scripts, fiction
Model positionLegacy release; use Claude Sonnet 4.6 for new work.

What makes Claude Sonnet 4 different

Sonnet 4 is a legacy step in the Claude line. Its page remains available for people searching for that exact version, but the current Sonnet routes offer stronger defaults. Use it for historical comparison, then run the same brief in Sonnet 4.6 or 5 before committing to important output.

What Claude Sonnet 4 is best for

  • High-quality writing: essays, articles, scripts, fiction
  • Reading long documents and answering questions about them
  • Sensitive or complex topics that need a thoughtful tone
  • Coding tasks that span multiple files or components
  • Translation and tone-matching across languages

How to use Claude Sonnet 4

Step 1 Give Claude Sonnet 4 a writing brief with the audience, goal, tone and any source material, and let it produce essays, scripts or fiction that hold a consistent voice from start to finish.
Step 2 For sensitive or complex subjects, ask Claude Sonnet 4 to handle the topic thoughtfully, weigh perspectives carefully, and flag where it is uncertain.
Step 3 Use follow-ups to deepen the analysis, match a specific tone, or extend a multi-file coding task across the components it already understands.

Example prompts

Unlimited Claude Sonnet 4, free for 7 days

You are on the free tier. Go unlimited on every premium model, with image and PDF uploads and saved history. No charge today, cancel anytime.

  • Unlimited use
  • Premium models
  • No ads
  • 7-day free trial
  • Cancel anytime
See all plans →

Frequently asked questions

Why is Claude Sonnet 4 a premium model?

It's the most expensive model on the platform per token (4× the multiplier). The output quality on long, complex tasks is usually worth the cost.

Does Claude have a longer context than ChatGPT?

Anthropic's models support large context windows, making them strong for long documents and code.

Can Claude refuse to answer?

Claude is more likely than other models to push back on harmful or ambiguous requests. Rephrase the question if you hit a refusal.

What's the difference between Sonnet 4 and 3.7?

Sonnet 4 is newer and stronger overall, but 3.7 is faster and cheaper for everyday writing.

Related tools and comparisons

ChatGPT alternatives Compare free ChatGPT-style tools. Claude alternatives Compare Claude-like writing and reasoning tools. AskAI.free vs Claude See when to use AskAI.free or Claude directly. AI models FAQ Learn which model fits each task.

Try other AI models free

Ask Claude Sonnet 5 Free Anthropic model (New) - no signup for your first question. Ask Claude Opus 4.7 Free Anthropic model (Premium) - no signup for your first question. Ask Claude Sonnet 4.6 Free Anthropic model - no signup for your first question. Ask ChatGPT 5.6 Terra Free OpenAI model (New) - no signup for your first question.

More questions about AI models? Read our AI models FAQ: comparisons, picks for coding/writing, and what each model is best at.