Claude Sonnet 5.5
by Anthropic
Today's price · per 1M tokens
Input
$2.00
per 1M tokens
Output
$10.00
per 1M tokens
Blended
$4.00
blended $/1M — 3:1 weighted input:output
Cached input
$0.100
5% of input — prompt caching
Price receipt
We read Anthropic's own pricing page on and found Claude Sonnet 5.5 listed with a price on the same row — that read is where the number above comes from, recorded as a price drop. We keep the page text we read; its content hash is 021bc760d5.
Overview
Anthropic's newest Sonnet and the second model of the Claude 5.5 family, launched 2026-09-28 as a faster, lower-cost complement to Opus 5.5. Anthropic says it is a clear upgrade over Sonnet 5, generates 30%+ faster and costs up to 30% less per task because it needs fewer tokens. List price is unchanged from Sonnet 5: $2/$10 per 1M tokens, cache reads $0.10 (5% of input, cut from $0.20 by 2026-10-07), cache writes $2.50; Batch API halves it to $1/$5; US-only inference is 1.1x. 1M-token context, 128K max output.
Capabilities
struck through = not supportedBenchmark performance
accuracy % · higher is better- AA Intelligence Index: 56 (Artificial Analysis composite across reasoning, knowledge and coding evals)
- AA-Omniscience Index: 32.3 (−100–100)
- Ranks #49 of 100 benchmarked models by average score
- Ranks #8 of 195 comparably-measured models by percentile score, across 4 independent measurements
- Ranks #129 of 195 comparably-tested models by normalized performance per dollar
- Strongest at Humanity's Last Exam — 55%, #10 of 81
Source: Vellum LLM Leaderboard · updated · See full rankings →
Specifications
- Provider
- Anthropic
- Context window
- 1M tokens
- Modality
- text, image
- Parameters
- Proprietary
- Open source
- No — proprietary
- Released
- Status
- Current
- Last updated
- Tags
Availability verified: — listed on Anthropic's own page