Model board / Claude Sonnet 5.5

Claude Sonnet 5.5

Name: Claude Sonnet 5.5
Brand: Anthropic
Price: 10.0 USD

latest Anthropic

Verified 2026-10-22 against the pages listed below. Prices are USD per 1M tokens, list rate — no committed-use, enterprise or volume discount.

Input

$2.00

Cached input

$0.1

Cache write

$2.50

Output

$10.00

Context window

1,000,000

Max output

128,000

Weights

closed

Caching

both

released 2026-09-28 at Sonnet 5's price; cache read cut from $0.20 to $0.10 on 2026-10-07. 1h cache write $4.00. The pricing page's model table still prints $0.20 in the cache-hit column, while the same page's multiplier section and the 2026-10-07 release note both state $0.10 — this row follows the dated change

full 1M window at standard rates; 128K max output per request, 300K on the Batch API with a beta header

read 0.05x input since 2026-10-07 (was 0.1x); 5m write 1.25x, 1h write 2x; caches from 512 tokens, half Sonnet 5's 1,024

Watch out

Not a drop-in swap for Sonnet 5 code: forced tool use (tool_choice any or tool) returns 400; thinking cannot be switched off — the lowest setting, between_tools, only drops the up-front pass; text between tool calls now arrives in thinking blocks; and on the Claude API the earlier computer_20251124 tool is refused

What we would use it for

Anthropic's balance of speed and capability, at Sonnet 5's price with half its cache read

What this has cost, week by week

Output price at each refresh since 2026-10-01. A vendor change is the provider changing its price. Our correction means this board changed what it prints and the provider's charge did not move — the two are never merged, because publishing the second as the first would be a price rise that never happened.

10-01 $10.00→10-08 $10.00→10-15 $10.00→10-22 $10.00

vendor change2026-10-08 · cached_in — $0.20 → $0.10 (0.1x → 0.05x input): Anthropic's release note of 2026-10-07 halves the Sonnet 5.5 cache read, and the pricing page's multiplier section states $0.10. The same page's model table still prints $0.20; the row follows the dated change.

Where these numbers came from

No number on this page was written that was not read from one of those pages on 2026-10-22. If one is wrong, send us the source URL and it is corrected in the next weekly refresh, with a changelog line saying what was wrong — contact@naderu.com.

Jobs this is one of our picks for

Content writing — Drafting and rewriting to a house style (content-writing)
Agentic coding — Long tool-use loops over whole repos (agentic-coding)
RAG and grounded answers — Answers built on passages you retrieved (rag-search)

Discussed in Naderu Weekly

Why web search busts your prompt cache — 2026-10-15
Stop paying for words you throw away — 2026-10-08
Same price, new rules — 2026-10-01

The rest of the board

This row sits alongside 76 others on the model board, refreshed every week. The same data as JSON, and the terms for using it, are at /board-data.