Claude Sonnet 5.5 · Anthropic

What does Claude Sonnet 5.5 cost to run in a coding agent?

Claude Sonnet 5.5 costs about $0.053 per average coding-agent request on our measured traffic, at list prices of $2 per million input and $10 per million output tokens. It is the everyday coding default, second only to Opus 5.5 on Terminal-Bench 4.0 at 61.8%.

List prices: Anthropic pricing, checked 2026-10-13. Request costs: Standard Compute gateway data, 79,301 coding-agent requests from 75 users, Sep 13 to Oct 12, 2026. Benchmark: Terminal-Bench 4.0 leaderboard. How we compute this

Run Claude Sonnet 5.5 in your agent from $19/month

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What Sonnet 5.5 costs per coding-agent request

Cost at list price	Sonnet 5.5
Prompt under 100K tokens50% of requests, 87% of input cached	$0.026
Prompt of 100K to 272K39% of requests, 88% of input cached	$0.064
Prompt over 272K tokens11% of requests, 86% of input cached	$0.14
Average request	$0.053
100 requests	$5.33
Median session16 requests; a session ends after 10 idle minutes	$0.74
A month of regular usemedian of 20 users active on 5+ days	$77.42

Each logged request priced at the vendor's list rates for its own token counts, including cache reads and any higher rate for long prompts. Average output: 698 tokens per request.

What to watch for

These figures assume 87% of input is read from cache at $0.10 per million, as in our traffic. A request that misses the cache (a new task, an edited system prompt, or a long pause) pays $2 per million on every input token, twenty times more, and writing the cache costs 1.25x input.

About Claude Sonnet 5.5

Claude Sonnet 5.5 is the mid-tier Claude, released September 28, 2026 as a faster, lower-cost complement to Opus 5.5. It is unusually close to the flagship: 56 on the Artificial Analysis Intelligence Index (#2 behind Opus 5.5), 61.8% on the Terminal-Bench 4.0 leaderboard (#2), and #3 on LMArena's WebDev board. Anthropic reports 70.6% on Terminal-Bench 4.0 against 10.3% for Sonnet 5, and says it runs over 30% faster and costs up to 30% less than its predecessor. It has a 1M-token context window and 128K output; effort defaults to high on the API and medium in Claude Code.

Sources: Anthropic announcement · Artificial Analysis · Terminal-Bench 4.0 · SWE-Bench Pro V2

Claude Sonnet 5.5 FAQ

How much does Claude Sonnet 5.5 cost per coding-agent request?

$0.053 on average at list price, $5.33 per 100 requests, and $0.74 for a median 16-request session. That is 79,301 real coding-agent requests (Sep 13 to Oct 12, 2026) priced at Anthropic's list rates; the median request sent 99,534 input tokens, 87% of input was read from cache, and requests returned 698 output tokens on average.

Does Claude Sonnet 5.5 charge more for long prompts?

No. Claude Sonnet 5.5 bills the same rate per token up to its 1M-token context window.

Is Claude Sonnet 5.5 good for AI agents?

The everyday default for coding agents, escalating to Opus 5.5 only for the hardest tasks. On our editorial scoring it rates 9.8/10 for agentic ability and 9.8/10 for output quality. Near-Opus 5.5 results: #2 on Artificial Analysis (56) and Terminal-Bench 4.0 (61.8%).

What is Claude Sonnet 5.5's context window?

Claude Sonnet 5.5 has a 1M-token context window — large enough to hold sizeable codebases or document sets in a single run. Anthropic is the maker.

Can I self-host Claude Sonnet 5.5?

No — Claude Sonnet 5.5 is a proprietary, hosted-only model from Anthropic. You access it through an API (e.g. OpenRouter) rather than running the weights yourself.

What are the downsides of Claude Sonnet 5.5?

The main trade-offs: Artificial Analysis flags it as very verbose, which adds output tokens; Released September 2026, so its long-run track record is still short. It's strongest for the everyday default for coding agents, escalating to Opus 5.5 only for the hardest tasks.