The sweet spot in Anthropic's lineup for serious coding and writing work — strong enough to replace Opus 4 in most real-world tasks.
88
Coding
87
Writing
83
Research
20
Images
48
Value
85
Long Context
Use this when
Complex coding tasks, nuanced writing, and multi-step research where you need near-flagship quality without paying flagship prices.
Skip this if
You need fast, high-volume inference on simple tasks — Claude Haiku 3.5 or Gemini Flash will cost a fraction of the price for straightforward summarization or classification.
Pricing
$3.00/1M in
$15.00/1M out
→0%since May 2026
Context
200k tokens
Speed
Balanced
Claude Sonnet 4specs & pricing
Verified Sep 4, 2026 against the AI Gateway catalog
Pricing at $3 input / $15 output positions this as a 'balanced' tier model, but output costs are notably higher than comparable models like GPT-4o ($10 output). Extended context (200K) is available by default. Check Anthropic's API for rate limits and availability by tier.
Strong instruction-following and nuanced prose generation that rivals GPT-4o-class models
200K context window handles long codebases, documents, and multi-turn conversations effectively
Excellent at agentic and multi-step coding tasks, including debugging and refactoring
More reliable refusals calibration than earlier Claude versions — less over-cautious on edge cases
Weaknesses
No native image generation; multimodal is input-only (vision), lagging behind Gemini 1.5 Pro on image-heavy workflows
Output cost of $15/1M tokens makes it expensive at scale compared to GPT-4o Mini or Gemini Flash equivalents
Reasoning depth still trails Claude Opus 4 and o3-class models on highly complex logical or mathematical problems
Real-world use cases
What people actually use Claude Sonnet 4 for.
Refactoring a 5,000-line Python codebase with consistent style and bug identification across the full file
Drafting a detailed technical blog post or whitepaper with accurate citations and structured argumentation
Analyzing a 150-page legal or financial PDF and extracting key clauses or risk factors
How Claude Sonnet 4 compares
The nearest models people weigh against it, and what actually separates them.
vs Claude 3.5 Sonnet — Against Claude 3.5 Sonnet (Anthropic), Claude Sonnet 4 runs about 50% cheaper per token. Take Claude Sonnet 4 unless you specifically need what Claude 3.5 Sonnet does better.
vs Claude Fable 5 — Against Claude Fable 5 (Anthropic), Claude Sonnet 4 runs about 70% cheaper per token, gives up 5x on context and answers faster. Take Claude Sonnet 4 unless you specifically need what Claude Fable 5 does better.
vs Claude Fable 5.1 — Against Claude Fable 5.1 (Anthropic), Claude Sonnet 4 runs about 70% cheaper per token, gives up 5x on context and answers faster. Take Claude Sonnet 4 unless you specifically need what Claude Fable 5.1 does better.
Price History
Claude Sonnet 4 pricing over time
→0% since May 19
90 data points · tracked daily since May 19, 2026
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Start using Claude Sonnet 4
Complex coding tasks, nuanced writing, and multi-step research where you need near-flagship quality without paying flagship prices.. Start free — no card required.
Claude 3.5 Sonnet is Anthropic's mid-cycle flagship model, balancing strong reasoning, coding, and instruction-following with a 200K context window. It sits between Haiku and Opus in Anthropic's lineup, offering near-flagship quality at a lower cost than top-tier models.
Verdict
One of the best models for coding and complex instruction-following, but its premium pricing demands premium use cases.
Quality score
81%
Pricing
$6.00/1M in
$30.00/1M out
Speed
Balanced
3/5 speed
Context
200k tokens
Pricing at $6 input / $30 output per million tokens is significantly higher than GPT-4o ($2.50/$10). Best accessed via Anthropic API or Amazon Bedrock. Claude 3.5 Sonnet (October 2024 version) supersedes the June 2024 release with improved performance.
Anthropic's new Mythos-class flagship and the most capable coding model anyone can use — 80.3% SWE-Bench Pro, an 11-point jump over Opus 4.8. 1M context, 128K output, native parallel subagents. Released June 9, 2026.
Verdict
New global #1 — 80.3% SWE-Bench Pro, the most capable model generally available.
Quality score
98%
Pricing
$10.00/1M in
$50.00/1M out
Speed
Deliberate
2/5 speed
Context
1M tokens
Launched June 9, 2026 as the public, Mythos-class release. Available on the Claude API, Microsoft Foundry, and Google Vertex AI. Free for all users until June 22, 2026. Same underlying model as Claude Mythos 5, with safeguards that block specific high-risk cyber responses.
Coding leaderSWE-Bench Pro #1Mythos-classParallel subagentsAgenticLong contextPremiumNew
Best for
The hardest coding tasks, autonomous multi-step agents, and frontier-grade reasoning
Anthropic's September 1, 2026 frontier release and the new capability ceiling for coding, agents, and scientific work. Base pricing is unchanged at $10/$50, but cache reads dropped 75% to $0.25/1M — roughly 25% cheaper on typical workloads and up to 45% cheaper on agentic ones. 1M context, 128K output, adaptive thinking always on.
Verdict
New frontier leader — better than Fable 5 on every published benchmark, and cheaper to run.
Quality score
98%
Pricing
$10.00/1M in
$50.00/1M out
Speed
Deliberate
2/5 speed
Context
1M tokens
Released September 1, 2026 alongside Claude Mythos 5.1, the first update to the Mythos-class line since Fable 5 on June 9. API ID claude-fable-5-1; generally available on the Claude API, Amazon Bedrock, Google Cloud, and Microsoft Foundry. Published launch numbers (Fable 5.1 / Fable 5 / Opus 5 / GPT-5.6 Sol): Terminal-Bench-Science 0.1 52.6 / 24.7 / 29.0 / 22.4; Terminal-Bench 4.0 55.8 / 42.0 / 52.3 / 37.3; CursorBench 3.2.0 73.4 / 70.5 / 70.0 / 67.2; AutomationBench 31.4 / 17.1 / 26.9 / 19.6; OSWorld 2.0 strict 41.7 / 36.1 / 39.6; Humanity's Last Exam (no tools) 60.9 / 57.8 / 56.6; GDPval-AA v2 1853 / 1723 / 1824 / 1711. GDPval-AA v2 is rescaled from the v1 numbers quoted on the Fable 5 page and is not directly comparable to them.
Pricing moves, ranking shifts, and capability updates.
New ModelMar 27, 2026
Anthropic: Claude Sonnet 4 — added to UseRightAI
Anthropic: Claude Sonnet 4 (Anthropic) is now indexed. The sweet spot in Anthropic's lineup for serious coding and writing work — strong enough to replace Opus 4 in most real-world tasks.
Claude Sonnet 4 costs $3 per million input tokens and $15 per million output tokens on the API, with cached input at $0.3 per million. A month of 10M input and 2M output tokens runs about $60.00 at list price, before any batch or caching discounts.
What is the context window of Claude Sonnet 4?
Claude Sonnet 4 has a 1M tokens context window, with up to 8k tokens of output per response. That is the total of prompt plus response the model can hold in one request.
What is the knowledge cutoff of Claude Sonnet 4?
Claude Sonnet 4's training data runs through March 31, 2025, and the model was released on May 22, 2025. For anything after that date it needs web search or documents in the prompt.
What is Claude Sonnet 4 best for?
Claude Sonnet 4 is best for complex coding tasks, nuanced writing, and multi-step research where you need near-flagship quality without paying flagship prices.. It is a strong fit when that workflow matters more than the tradeoffs around balanced pricing and balanced speed.
When should I avoid Claude Sonnet 4?
You need fast, high-volume inference on simple tasks — Claude Haiku 3.5 or Gemini Flash will cost a fraction of the price for straightforward summarization or classification.
What is a cheaper alternative to Claude Sonnet 4?
GPT-5.1-Codex-Max (OpenAI) at $1.25/1M/1M input against Claude Sonnet 4's $3.00/1M/1M — roughly 38% less per token all in. The strongest choice for serious software engineering work, provided you can absorb the output-side pricing. Compare it first if Claude Sonnet 4's pricing is the thing stopping you.
What is a faster alternative to Claude Sonnet 4?
Claude 3.5 Sonnet — balanced against Claude Sonnet 4's balanced, with 200k tokens of context. Worth the swap when response time is what your users notice rather than the last few points of reasoning depth.
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