Claude Models

1:46 As of Nov 6, 2026, Anthropic's current Claude models are Claude Fable 5.1, Claude Opus 5.5, Claude Sonnet 5.5 and Claude Haiku 5.5, and Anthropic's own advice is to start with Opus 5.5 for most work and move to Fable 5.1 for the hardest reasoning and long agentic jobs (Models overview, Anthropic docs, read Nov 6, 2026). A fifth model, Claude Mythos 5.1, is the same model as Fable 5.1 with looser safeguards for cybersecurity and life sciences work, and only verified organizations can use it (Introducing Claude Mythos and Fable 5.1, Anthropic, Sep 15, 2026). All four general models read text and images, use tools, and share a 1M-token context window and 128K-token output limit.

Quick facts

Sources: Models overview and Pricing, Anthropic docs; Plans and pricing, Claude; all read Nov 6, 2026.

The current models side by side

Sources: Models overview, Pricing and Model deprecations, Anthropic docs, read Nov 6, 2026; Plans and pricing, Claude, read Nov 6, 2026; launch posts linked below.

Haiku 5.5 is the only current model with tiered pricing: a prompt over 100,000 tokens costs $0.50 input and $2.50 output per million tokens. The Fable 5.1 retirement floor of Sep 1, 2027 matches its release on Sep 1, 2026, the day the model and its announcement post went public; Anthropic's newsroom lists the post on Sep 15, 2026.

Which Claude model should you use?

0:00 Anthropic's docs give a short rule: start with Claude Opus 5.5, and move to Claude Fable 5.1 only when Opus 5.5 at a higher effort level still falls short in your own tests (Models overview, read Nov 6, 2026). In practice the choice comes down to cost and speed:

1. Most coding and knowledge work: Opus 5.5. Anthropic says it works "at the level of" Fable 5.1 on most tasks at well under half the price (Introducing Claude Opus 5.5, Sep 22, 2026).
2. Hardest long-running agent tasks and science: Fable 5.1, the one Anthropic calls its most capable widely released model.
3. Everyday chat and high-throughput coding on a budget: Claude Sonnet 5.5, at half the price of Opus 5.5.
4. Classification, extraction, routing and subagents: Claude Haiku 5.5, which costs a tenth of Sonnet 5.5 for prompts under 100,000 tokens.

Independent measurements do not always follow the price ladder. On Artificial Analysis's Intelligence Index, Opus 5.5 at max effort scores 59, Sonnet 5.5 at max 55 and Fable 5.1 at its best 50 (Models leaderboard, Artificial Analysis, read Nov 6, 2026). On the Terminal-Bench 4.0 leaderboard, Opus 5.5 leads at 64.85%, with Sonnet 5.5 at 61.82% and Fable 5.1 at 57.88% (read Nov 6, 2026). Fable 5.1's case rests mostly on Anthropic's own science and long-horizon results; see Claude Benchmarks.

Claude Mythos 5.1

Claude Mythos 5.1 is not in the docs' comparison table. Anthropic describes it as the same model as Fable 5.1 with safeguards designed for defensive security and life sciences research, available through the Cyber Verification Program and the Life Sciences Verification Program and "currently limited to a set of US organizations" (Introducing Claude Mythos and Fable 5.1, Sep 15, 2026). Its API price is the same as Fable 5.1's (Pricing, read Nov 6, 2026).

Which models are in the Claude apps?

The plan decides which models appear in the model picker next to the send button (Plans and pricing, read Nov 6, 2026):

• Free: Sonnet 5.5 and Haiku 5.5. No Opus or Fable.
• Pro ($20 a month): Opus 5.5, Sonnet 5.5 and Haiku 5.5; Fable 5.1 is available but paid for with usage credits.
• Max and Ultra: all four, with Fable 5.1 included up to half of the weekly limit.
• Team and Enterprise: all four; on Team, Fable 5.1 counts against half of the weekly limit on premium seats.

See Claude Plans and Pricing and Claude Usage Limits for what each plan costs. Fable models do not work in Voice Mode (Use voice mode, Claude Help Center, read Nov 6, 2026). In Claude Code, Opus 5.5 is the default model on Pro, Max, Ultra, Team, Enterprise and the API (Model configuration, Claude Code docs, read Nov 6, 2026).

What do the model names mean?

Haiku, Sonnet and Opus have named Anthropic's small, middle and large models since the Claude 3 family of Mar 2024. Fable arrived in Jun 2026 as a tier above Opus: Anthropic called Claude Fable 5 "a Mythos-class model" for general use, and explained that "Fable" comes from the Latin fabula and "Mythos" from the Greek word for the same idea (Claude Fable 5 and Claude Mythos 5, Jun 9, 2026). The number is the generation; a point release such as 5.5 is a newer model in the same family, not a patch.

Older models still on the API

The docs list these legacy models as still available on Nov 6, 2026: Claude Fable 5, Opus 5, Opus 4.8, Opus 4.7, Opus 4.6, Opus 4.5, Sonnet 5, Sonnet 4.6 and Haiku 4.5 (Models overview). Claude Sonnet 4.5 is deprecated and retires on Nov 30, 2026, and Opus 4.5 may retire from Nov 24, 2026. Every release since Mar 2023 is on Claude Model History, with the Claude 4 Models and Claude 3 Models on pages of their own.

Frequently asked questions

What is the best Claude model? Anthropic calls Claude Fable 5.1 its most capable widely available model, but its docs tell most users to start with Claude Opus 5.5, which costs far less. Independent leaderboards such as Terminal-Bench 4.0 and Artificial Analysis's index ranked Opus 5.5 above Fable 5.1 as of Nov 6, 2026.

Which Claude model is free? Claude's Free plan includes Claude Sonnet 5.5 and Claude Haiku 5.5, with limits every five hours and every week. Opus and Fable need a paid plan.

What is the difference between Claude Opus, Sonnet and Haiku? They are Claude's large, middle and small tiers: Opus is the most capable of the three, Sonnet balances speed and cost, and Haiku is the fastest and cheapest. Fable sits above Opus.

How big is Claude's context window? All four current Claude models accept 1M tokens of context and can write up to 128K tokens in one response on the API. In the apps, the size depends on the model and plan; see Claude Context Window.

Can I choose the Claude model in the app? Yes. Click the model name next to the send button in Claude to switch models and, on most current models, set the effort level (Using extended thinking, Claude Help Center, read Nov 6, 2026). See Extended and Adaptive Thinking.

Is Claude Mythos available to the public? No. Claude Mythos 5.1 is limited to organizations admitted to Anthropic's cyber and life sciences verification programs, and as of Sep 15, 2026 those were US organizations only.

Sources

• Models overview, Anthropic docs, read Nov 6, 2026
• Pricing, Anthropic docs, read Nov 6, 2026
• Model deprecations, Anthropic docs, read Nov 6, 2026
• Plans and pricing, Claude, read Nov 6, 2026
• Introducing Claude Mythos and Fable 5.1, Anthropic, Sep 15, 2026
• Introducing Claude Opus 5.5, Anthropic, Sep 22, 2026
• Introducing Claude Sonnet 5.5, Anthropic, Sep 28, 2026
• Introducing Claude Haiku 5.5, Anthropic, Oct 7, 2026
• Claude Fable 5 and Claude Mythos 5, Anthropic, Jun 9, 2026
• Model configuration, Claude Code docs, read Nov 6, 2026
• Using extended thinking, Claude Help Center, read Nov 6, 2026
• Use voice mode, Claude Help Center, read Nov 6, 2026
• Terminal-Bench leaderboard, tbench.ai, read Nov 6, 2026
• Which Claude model should you use?, Claude, Sep 18, 2026 (video)
• Models leaderboard, Artificial Analysis, read Nov 6, 2026