Anthropic
Claude Sonnet 5.5
Claude Sonnet 5.5 is a Anthropic model with 1M context, $2 in / $10 out per million tokens, last verified October 1, 2026. Open weights: no. Public-board scores are linked to the publisher; vendor-only figures stay in the watch-out, not on the board.
Anthropic’s newer Sonnet model for everyday coding and knowledge work at the same $2/$10 token rates as Sonnet 5.
Recorded profile verification October 1, 2026Individual provider fields may change
| Specification | Claude Sonnet 5.5 |
|---|---|
| Provider | Anthropic |
| Tier | Balanced |
| Context window | 1M |
| Max output | 128K |
| Input / 1M tokens | $2 |
| Output / 1M tokens | $10 |
| Weights | Closed |
| Parameters | Not verifiedUnverified |
| Reasoning levels | low, medium, high, xhigh, max |
| Modalities | text, image |
| API model id | claude-sonnet-5-5 |
| Released | September 28, 2026 |
Pricing tiers: Standard $2/$10 per MTok with no long-context surcharge; cache reads $0.20, 5-minute writes $2.50 and 1-hour writes $4. Batch $1/$5. US-only inference adds 10% where supported. The 300K output limit requires the Batch API beta header output-300k-2026-03-24; standard output stays 128K. Knowledge cutoff Jun 2026; retirement not sooner than September 28, 2027.
Publisher evidence
Published benchmark results
Each result keeps its source date visible. Dates refer to source publication or capture unless the source explicitly states when it measured the result. A missing benchmark is not treated as a zero.
| Benchmark | Score | Source date | Source |
|---|---|---|---|
| Artificial Analysis Intelligence Index [max]Claude Sonnet 5.5 (max with fallback) | 56 | 2026-10-01 | Artificial Analysis · View source |
| Terminal-Bench 4.0 | 70.6% | 2026-10-01 | Anthropic (vendor-reported) · View source |
| Terminal-Bench 4.0 [max] | 63.6% | 2026-10-01 | Artificial Analysis (independent, mini-swe-agent) · View source |
| CursorBench 4.0 [max] | 55.5% | 2026-10-01 | Cursor (vendor-run coding agent) · View source |
| Humanity's Last Examwith tools | 64.5% | 2026-10-01 | Anthropic (vendor-reported) · View source |
| FrontierCode 1.1 (Main) [xhigh] | 52.1% | 2026-10-01 | Anthropic (vendor-reported) · View source |
| OSWorld 2.1partial task set | 80.1% | 2026-10-01 | Anthropic (vendor-reported) · View source |
Best for
- Everyday coding
- Document and slide creation
- Fast iteration
Watch out
History
Claude Sonnet 5.5 timeline
Release and status events for this model that passed two-source verification — dated, sourced, and linked.
- Claude Sonnet 5.5ReleaseSeptember 28, 2026
Anthropic releases Sonnet 5.5 at $2/$10 per million tokens, with 1M context and 128K standard output. Adaptive thinking is enabled by default.
Anthropic Sonnet 5.5 announcement
Source receipts
Catalog figures for this model were checked against the following sources.
- Claude model overview — whole-profile source check October 1 (accessed 2026-10-01)
- Claude current API pricing, caching and inference geography (accessed 2026-10-01)
- Anthropic release announcement (accessed 2026-10-01)
- Claude Platform Sonnet 5.5 specifications (accessed 2026-10-01)
- Claude models overview (accessed 2026-10-01)
- Anthropic selectable effort levels (separate from adaptive thinking mode) (accessed 2026-10-01)
Common questions
Claude Sonnet 5.5
Answered from the verified figures on this page rather than general guidance.