Anthropic

Claude Sonnet 5.5 API pricing.

Claude Sonnet 5.5 is Anthropic’s model on the API market, released 28 Sept 2026. Prices are per million tokens in USD, as last read from the price list.

$2.00Input / 1M
$10Output / 1M
1MContext
128KMax output
Capability scores
Epoch AI
Maths3 of 4 benchmarks90
Science and knowledge2 of 2 benchmarks70
CodingNot tested by Epoch
Reasoning and puzzles2 of 2 benchmarks59
Agents and long tasks2 of 3 benchmarks33

Each bar is this model's score in that area. The white tick marks the best score any model Epoch has tested reaches there.

Epoch Capabilities Index
167
Range 164 to 171 · #5 of 271 models Epoch has scored
Maths
90average of 3 of 4 Epoch results
FrontierMath (tiers 1 to 3) (max)89%
FrontierMath (tier 4) (max)80%
OTIS Mock AIME (max)100.0%
Science and knowledge
70average of 2 of 2 Epoch results
GPQA Diamond (max)96%
SimpleQA Verified (max)47%
Reasoning and puzzles
59average of 2 of 2 Epoch results
Chess puzzles (max)59%
Mystery game puzzles (max)65%
Agents and long tasks
33average of 2 of 3 Epoch results
Furniture assembly (max)75%
SpireClimb (game agent) (max)1.3%

The index combines many benchmarks into one general-capability score; the range is how sure Epoch is of the number. Each area score is this site's average of the model's Epoch results in that area, where 0 is what guessing would score and 100 is perfect. Compare every model, and value for money →

Source: Epoch AI, Capabilities & benchmarking (licensed CC BY 4.0). Data refreshed 2 November 2026. These are Epoch's own tests; other benchmark sites can rank models differently.

Cheaper models that come close
Our working on Epoch's index
  1. GPT-6.1 Terra · OpenAIindex 168.11 · 50% cheaper

Models within 5 points of Claude Sonnet 5.5 on Epoch's Capabilities Index that cost less, comparing a typical chat mix (three parts input to one part output). A few points of index is a small difference and says nothing about your task: a place to start testing, not a verdict. Capability against price for every model.

Specification
USD per million tokens
Provider
Anthropic
Model id
anthropic/claude-sonnet-5.5
Input
$2.00
Output
$10
Cached input
$0.10
Context window
1M tokens
Maximum output
128K tokens
Takes
text, image, file
Returns
text
Tool use
Yes
Reasoning
Yes
Released
28 Sept 2026
First tracked
28 Sept 2026

At $2.00 per million input tokens, Claude Sonnet 5.5 is dearer than 264 of the 340 models on the price list.

Price changes
Tracked since 17 Sept 2026

No price change has been recorded since tracking began on 17 Sept 2026. Prices are checked every six hours, and any change is listed here and on model changes.

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Coverage
6 stories
  1. Google Cloud AI & Machine Learning ·
    Claude Opus 5.5 and Claude Sonnet 5.5 are now available in Google Antigravity
  2. Tom's Guide AI ·
    Claude Sonnet 5.5 just launched — here's why it's about to become your daily driver
  3. Simon Willison's Weblog ·
    Claude Sonnet 5.5
  4. AWS Machine Learning Blog ·
    Introducing Claude Sonnet 5.5 on AWS
  5. The Decoder ·
    Anthropic's Claude Sonnet 5.5 nearly matches Opus 5.5 on benchmarks while costing up to 30 percent less per task
  6. SiliconANGLE AI ·
    Anthropic debuts Claude Sonnet 5.5 running 30% faster than the previous-generation AI model
Other entries for this model
More from Anthropic
Cheapest input first
  1. Claude Haiku 5.5$0.10 in · $0.50 out
  2. Claude Haiku 4.5$1.00 in · $5.00 out
  3. Claude Sonnet 5$2.00 in · $10 out
  4. Claude Sonnet 4.6$3.00 in · $15 out
  5. Claude Sonnet 4.5$3.00 in · $15 out
  6. Claude Opus 5.5$4.00 in · $20 out
  7. Claude Opus 5$5.00 in · $25 out
  8. Claude Opus 4.8$5.00 in · $25 out

Prices and specifications come from OpenRouter’s catalogue, last read 2 Nov 2026. A provider’s own price may differ; how this is collected.