One agent session
1M input tokens and 100K output tokens, no caching.
- Input1M x $2 = $2.00
- Output0.1M x $10 = $1.00
$3.00per session
Anthropic - Closed weights
Claude Sonnet 5.5 pricing and specs
Claude Sonnet 5.5 is a closed-weights model from Anthropic that costs $2 per 1M input tokens and $10 per 1M output tokens on the first-party API, with a 1M-token context window.
Last verified from platform.claude.com. All sources
- Input / 1M
- $2
- Output / 1M
- $10
- Context
- 1M tokens
- Weights
- Closed
Pricing per 1M tokens
| Item | Price / 1M tokens |
|---|---|
| Input | $2 |
| Output | $10 |
| Cache read | $0.10 |
| Cache write (5 minutes) | $2.50 |
| Cache write (1 hour) | $4 |
| Batch inputBatch requests | $1 |
| Batch outputBatch requests | $5 |
Note: Cache reads cut from $0.20 to $0.10 per MTok (0.05x base input) on 2026-10-07 per the release notes.
Specs
- Context window
- 1,000,000 tokens
- Max output
- 128,000 tokens
- Release date
- Provider
- Anthropic
- API model id
claude-sonnet-5-5- Vercel AI Gateway id
anthropic/claude-sonnet-5.5- Weights
- Closed weights
What Claude Sonnet 5.5 costs in practice
Worked from the standard list rates above, with the math shown so you can swap in your own token counts.
A chat app
10,000 requests a day at 2K input and 500 output tokens each.
- Input20M x $2 = $40.00
- Output5M x $10 = $50.00
$90.00per day
$2,700.00 per 30-day month
The same session at a 90% cache hit
90% of the input is read from the prompt cache. The one-time cache write premium is not included.
- Cached input0.9M x $0.10 = $0.09
- Uncached input0.1M x $2 = $0.20
- Output0.1M x $10 = $1.00
$1.29per session
Compare with
| Model | Input / 1M | Output / 1M |
|---|---|---|
| Claude Sonnet 5.5 (this page) | $2 | $10 |
| GLM-5.3Z.ai | $1.40 | $4.40 |
| Claude Haiku 5.5Anthropic | $0.10 | $0.50 |
| Claude Opus 5.5Anthropic | $4 | $20 |
| Claude Fable 5.1Anthropic | $10 | $50 |
Related reading
- Opus 5.5 vs Sonnet 5.5 vs Haiku 5.5: Which Claude Model to UseSonnet 5.5 is the default, Opus 5.5 is for open-ended long-horizon work, and Haiku 5.5 is for bounded steps and subagents. Prices, benchmarks, cost math.
- Claude Sonnet 5.5 Developer Guide: Pricing and API ChangesClaude Sonnet 5.5 costs $2/$10 per million tokens, and cache reads fell to $0.10 on October 7 - half of Opus 5.5 on every line. Pricing math and API changes.
- Claude Code Idle Compaction: What It Does and How to Turn It OffClaude Code 2.1.299 compacts sessions over 200K tokens after about 54 idle minutes. How the cache math works, the setting to turn it off, and when to keep it.
- Claude Code Desktop SneakPeek Flaw: Fixed Version and What To DoSneakPeek (CVSS 8.7) let a poisoned HTML file read SSH keys and cloud credentials via the Claude Code Desktop preview pane. Fixed in Claude Desktop 1.30096.1.
- Anthropic Self-Replicating AI Research: What Small Models Can Actually DoAnthropic's Frontier Red Team says small open models may be months from self-replicating across cheap IoT devices. What it measured and where the claim is thin.
- Reverse Engineer Anything (REA): What the MCP Server Does and Where the Line IsREA (Reverse Engineer Anything) is an MIT-licensed MCP server that lets Claude Code, Codex or Cursor inspect binaries, Electron apps and APKs. How to try it.
FAQ
How much does Claude Sonnet 5.5 cost per million tokens?
Claude Sonnet 5.5 costs $2 per 1M input tokens and $10 per 1M output tokens on Anthropic's first-party API, per platform.claude.com on October 9, 2026. Per 1M tokens, cache reads cost $0.10, and the batch rate is $1 input and $5 output.
What is Claude Sonnet 5.5's context window?
Claude Sonnet 5.5 has a 1,000,000-token context window and returns up to 128,000 output tokens per response.
Are Claude Sonnet 5.5's weights open?
No. Claude Sonnet 5.5 is a closed-weights model. You call it through Anthropic's API as claude-sonnet-5-5 or through Vercel AI Gateway as anthropic/claude-sonnet-5.5.
When was Claude Sonnet 5.5 released?
Anthropic released Claude Sonnet 5.5 on September 28, 2026.
Sources
Last verified from platform.claude.com.
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