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Claude Sonnet 5 vs Claude Opus 4.8

Claude Opus 4.8 scores higher than Claude Sonnet 5 on all 5 public leaderboards that rate both. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, Claude Sonnet 5 is at 43.5 and Claude Opus 4.8 at 47.8 (out of 100).

Scores as published by each board; table composed September 24, 2026.

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Leaderboard by leaderboard

BoardClaude Sonnet 5Claude Opus 4.8Higher
LMArena
Elo (community votes)
1,542.51,555.2Claude Opus 4.8
LiveBench
global average (0-100)
7676.2Claude Opus 4.8
SimpleBench
AVG@5 % (private set)
60.664.8Claude Opus 4.8
Vals AI
Vals Index accuracy % · weighted finance + coding tasks
59.660.9Claude Opus 4.8
Artificial Analysis
intelligence index · measured runs only
38.241.8Claude Opus 4.8

Raw scores are each board's own scale, so compare within a row, not across rows. Full table: the bench index.

Claude Sonnet 5 at a glance

Developer
Anthropic
Status
Live since June 30, 2026
API price
$2 input / $10 output per 1M tokens · Anthropic, claude-sonnet-5
Context window
1M tokens

Shipped Jun 30.

Full Claude Sonnet 5 tracker →

Claude Opus 4.8 at a glance

Developer
Anthropic
Status
Live since May 27, 2026
API price
$5 input / $25 output per 1M tokens · Anthropic, claude-opus-4-8
Context window
1M tokens

Live.

Full Claude Opus 4.8 tracker →

Claude Sonnet 5 vs Claude Opus 4.8: quick answers

Which is better, Claude Sonnet 5 or Claude Opus 4.8?

It depends on what you measure. Claude Opus 4.8 scores higher than Claude Sonnet 5 on all 5 public leaderboards that rate both. Claude Opus 4.8's widest lead is on SimpleBench. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, Claude Sonnet 5 is at 43.5 and Claude Opus 4.8 at 47.8 (out of 100).

Which is newer, Claude Sonnet 5 or Claude Opus 4.8?

Claude Sonnet 5. It went live on June 30, 2026, 34 days after Claude Opus 4.8 (May 27, 2026).

Which is cheaper, Claude Sonnet 5 or Claude Opus 4.8?

Claude Sonnet 5 is cheaper on both input and output. On each vendor's own API, Claude Sonnet 5 is $2 input / $10 output per million tokens and Claude Opus 4.8 is $5 input / $25 output per million tokens. Prices as published in the models.dev catalog, as of 2026-09-24.

Which has the bigger context window, Claude Sonnet 5 or Claude Opus 4.8?

Neither. Both take 1M tokens.

Who makes Claude Sonnet 5 and Claude Opus 4.8?

Both are from Anthropic.

Where do these numbers come from?

Each score is the leaderboard's own published figure, read by ArtificialWatch (table composed September 24, 2026). Boards measure different things, so raw scores are only comparable within a row.

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