Model Tracker

Claude Opus 4.8

Claude Opus 4.8 is an AI model made by Anthropic. Anthropic released it on 28 May 2026. It is generally available. Its context window is 1,000,000 tokens.

Anthropic

Claude Opus 4.8 is an AI model made by Anthropic. Anthropic released it on 28 May 2026. It is generally available. Its context window is 1,000,000 tokens. Its longest answer is 128,000 tokens. Through the API it costs $5.00 per 1M tokens for input and $25.00 per 1M tokens for output. Its knowledge cutoff is January 2026.

Released: 28 May 2026 — platform.claude.com, read 16 October 2026
Status: Generally available — platform.claude.com, read 16 October 2026
Takes: Not confirmed: two readings disagree: text, image and text
Returns: Text — platform.claude.com, read 16 October 2026
Open weights: Not confirmed: The reviewed Anthropic pages do not state whether the model's weights are open.
Licence: Not confirmed: The reviewed Anthropic pages do not name a licence for the model.
Context window: 1,000,000 tokens — platform.claude.com, read 16 October 2026
Longest answer: 128,000 tokens — platform.claude.com, read 16 October 2026
Knowledge cutoff: January 2026 — platform.claude.com, read 16 October 2026
API price, input: $5.00 per 1M tokens — platform.claude.com, read 16 October 2026
API price, output: $25.00 per 1M tokens — platform.claude.com, read 16 October 2026
Where: Not confirmed: two readings disagree: api, app, cloud and api, app
Parameters: Not confirmed: The reviewed Anthropic pages do not publish a parameter count.
Model card: https://www-cdn.anthropic.com/0b4915911bb0d19eca5b5ee635c80fef830a37ea.pdf — www-cdn.anthropic.com, read 16 October 2026

Benchmarks

Measured by others, not by the maker: each score with the name the measurer gives the model and the setting it ran, its day and its licence.

Arena

Text Arena, claude-opus-4-8-high: 1,481 (1,478–1,485, 64,100 votes), published 15 October 2026
Text Arena, claude-opus-4-8: 1,474 (1,470–1,478, 65,172 votes), published 15 October 2026
Code Arena (WebDev), Claude Opus 4.8 (High): 1,556 (1,550–1,562, 18,500 votes), published 18 October 2026
Code Arena (WebDev), Claude Opus 4.8: 1,536 (1,530–1,542, 17,402 votes), published 18 October 2026
Vision Arena, claude-opus-4-8-high: 1,286 (1,279–1,292, 18,341 votes), published 9 October 2026
Vision Arena, claude-opus-4-8: 1,279 (1,272–1,285, 18,852 votes), published 9 October 2026

Arena’s leaderboard dataset (lmarena-ai/leaderboard-dataset on Hugging Face), CC BY 4.0: ratings from people’s votes between two anonymous models, as Arena publishes them. Data · CC BY 4.0

Epoch AI

Epoch Capabilities Index, Claude Opus 4.8: 158.3 (156.2–160.8), as of 19 October 2026
GPQA Diamond, claude-opus-4-8_max: 91.0% (± 1.9), run 7 June 2026
GPQA Diamond, claude-opus-4-8_low: 88.4% (± 2.3), run 6 August 2026
GPQA Diamond, claude-opus-4-8_none: 85.4% (± 2.5), run 6 August 2026
FrontierMath, tiers 1–3, claude-opus-4-8_max: 80.0% (± 2.4), run 10 June 2026
FrontierMath, tier 4, claude-opus-4-8_max: 56.1% (± 7.8), run 10 June 2026
OTIS Mock AIME 2024–2025, claude-opus-4-8_max: 98.3% (± 1.4), run 7 June 2026
OTIS Mock AIME 2024–2025, claude-opus-4-8_low: 97.8% (± 2.2), run 6 August 2026
OTIS Mock AIME 2024–2025, claude-opus-4-8_none: 84.4% (± 5.5), run 6 August 2026
SimpleQA Verified, claude-opus-4-8_max: 53.0% (± 1.6), run 27 August 2026

Epoch AI, ‘Capabilities & benchmarking’, epoch.ai/benchmarks, CC BY 4.0: Epoch AI’s own runs and its Capabilities Index. Data · CC BY 4.0

Questions

When was Claude Opus 4.8 released?

Anthropic released Claude Opus 4.8 on 28 May 2026.

Is Claude Opus 4.8 still available?

Yes: it is generally available, as Anthropic states it.

What is the context window of Claude Opus 4.8?

The context window of Claude Opus 4.8 is 1,000,000 tokens, as Anthropic prints it.

How much does the Claude Opus 4.8 API cost?

On the standard tier, Claude Opus 4.8 costs $5.00 per 1M tokens for input and $25.00 per 1M tokens for output, as Anthropic lists it.

What is the knowledge cutoff of Claude Opus 4.8?

The knowledge cutoff of Claude Opus 4.8 is January 2026.

Sources

Claude Opus 4.8 (read 16 October 2026)
Anthropic’s Transparency Hub (read 16 October 2026)
Claude Opus 4.8 System Card (read 16 October 2026)

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