Anthropic·#19 of 276 on the current board·cheaper than #13 Gemini 3.1 Pro Preview
Claude Sonnet 5.5 is a language model from Anthropic. It ranks #19 of 276 on ModelCap's current board, with an Index score of 77.3, modeled from its measured predecessor. Its score range of 63.6–90.9 spans positions #1–#57. It is listed at $2.00 per million input tokens and $10.00 per million output tokens across 2 providers. It reads up to 1M tokens of context and is available only through an API.
Figures as of 28 Sept 2026, 18:11 UTC · download the public dataset · methodology
Scores Anthropic publishes for this model, with the figures the same tables give for other models. They are the publisher describing its own model, not independent measurement. Rows marked as used placed this model’s launch estimate against peers ModelCap measures independently, with the replay-measured optimism haircut applied; the others played no part.
No general-family board lists this model yet. Its point estimate is the precision-weighted mean of every channel that spoke for it; each channel’s share is the weight it carried. Independent measurements replace this placement as boards list the model.
BES normalizes admitted public benchmark evidence for measured Index rows. Its legacy score and observables prior do not define the public language rank.
These adoption and deployment observations remain context only. They do not change this model's ModelCap Index score or rank.
The bounded 0–100 capability score blends each source’s competitive placement with its published achievement, then combines capability families. Evidence breadth adds a modest uncertainty adjustment; price and popularity are not part of benchmark-led rank.
insufficient-artifact-metadata
insufficient-artifact-metadata. This layer predicts from admitted evidence and safe metadata only. It never enters ModelCap Score or rank.
Not yet published: a pinned repository revision, the architecture and model type, a parameter count, safetensors weight metadata, the base model it derives from, a declared licence, a link to the licence terms, measured provider uptime, admitted benchmark results, results across several capability areas, results from more than one source, a confident match to its benchmark entries, pinned evaluation dataset versions.
A metadata completeness and deployability index—not a safety certification, quality grade, or production-readiness claim.
Market Gravity uses OpenRouter’s full-catalogue popularity order. Sparse Vercel top-ten observations appear only when published and do not affect the score.
This model is visible because it is available in the live catalogue, but it has no trustworthy community result yet. ModelCap does not infer a quality score from price, features, or market activity.
OpenRouter weekly popularity across the full model catalogue.
Independent providers versus the model's open or closed cohort, weighted by uptime.
Hugging Face 30-day downloads for open models; neutral for closed models.
Time since first public availability, on a six-month half-life.
anthropic/claude-sonnet-5.5Models within 3 places of #19 on the ModelCap Index.
Index score within 3 points of, or above, this model's, with a lower listed blended price (3:1 input:output).
The same publisher's other current models with a public Index position.
Claude Sonnet 5.5 holds ModelCap Index position #19 of 276 ranked language models as of 28 September 2026, with an Index score of 77.3 (interval 63.6–90.9); evidence: modeled · succession. The Index combines public benchmark boards with published uncertainty; the methodology page explains the weighting.
Claude Sonnet 5.5 is listed at $2.00 per 1M input tokens and $10.00 per 1M output tokens as of 28 September 2026 across 2 providers. Prices come from the OpenRouter catalogue and re-observe on every refresh. For 1,000 requests using 2,000 input and 500 output tokens each, the listed rates imply $9.00 total (2M input + 0.5M output). This excludes caching, batch discounts, prompt-length tiers, tool charges and retries; verify the chosen endpoint's rate and limits before budgeting.
Claude Sonnet 5.5 has a published context window of 1M tokens (1,000,000) and a maximum output of 128K tokens. Individual providers can serve less than the published maximum; the providers table lists each endpoint's own limit.
API only. No downloadable model weights are linked in the current source data; access is through a hosted API or product.
2 providers serve Claude Sonnet 5.5 through OpenRouter as of 28 September 2026: Claude Platform on AWS and Anthropic. Each provider's price, context limit, quantization and measured uptime are in the providers table above.
Claude Sonnet 5.5's Index position rests on the evidence listed on this page; it has no result on the public boards ModelCap tracks as separate leaderboards as of 28 September 2026. The evidence panel names each source and its publication date.
Claude Sonnet 5.5 first appeared in the catalogue on 28 Sept 2026. It is the current version in its family. Rank and price movements since then are recorded on the site's changes feed.