Claude Sonnet 4.6

The last Sonnet on the classic tokenizer, and the baseline this site uses for old-vs-new tokenizer comparisons.

API model ID	`claude-sonnet-4-6`
Context window	1M tokens
Max output	128K tokens
Input price	$3 per million tokens
Output price	$15 per million tokens
Knowledge cutoff	Aug 2025
Released	Feb 17, 2026
Tokenizer generation	Classic (Sonnet 4.6 and earlier)
Status	Active

From the announcement

Brought 1M context to the Sonnet tier.
Testers preferred it to Sonnet 4.5 about 70% of the time, and even to Opus 4.5 about 59% of the time.

Read Anthropic's announcement

Count tokens for Claude Sonnet 4.6 Estimate your monthly cost Check what fits in its context window

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