Claude Opus 5.5
About this model
Claude Opus 5.5 is an AI model from Anthropic, made available through the API on September 22, 2026. It can read up to 1,000,000 tokens in one request, roughly 1,875 pages of text, and write up to 128,000 tokens in a single answer. Besides text, it accepts images and files such as PDFs as input.
Through the API it costs $4 per million input tokens and $20 per million output tokens. It is among the more expensive models we track, a price usually reserved for the most capable, flagship-class models.
It supports extended reasoning: it can "think" step by step before answering, which helps on maths, code and complex questions. It can call tools and functions, so developers can connect it to search, databases or other software.
Quality scores
Rankings →- GPQA DiamondVery hard multiple-choice questions in biology, physics and chemistry, written by PhD experts. Random guessing scores 25%.90.6%#28 of 116
- AIME mathCompetition-level math problems in the style of the American Invitational Mathematics Examination. Share solved.100%#2 of 112
- FrontierMathOriginal, unpublished math problems written by professional mathematicians, from advanced to research level. Share solved.91.2%#2 of 73
- SimpleQA VerifiedShort factual questions. Measures how often the model gets facts right instead of making something up.72.2%#3 of 69
Where to use it
Companies that serve this model through an API: 11. Prices per million tokens, cheapest first.
| Provider | Inputi | Outputi | Contexti | Uptime (24 h)i |
|---|---|---|---|---|
Amazon BedrockCheapest | $4 | $20 | 1M | 99.9% |
AzureCheapest | $4 | $20 | 1M | 99.9% |
GoogleCheapest | $4 | $20 | 1M | 99.9% |
Claude Platform on AWSCheapest | $4 | $20 | 1M | 98.8% |
AnthropicOfficialCheapest | $4 | $20 | 1M | 99.6% |
Amazon Bedrock | $4.40 | $22 | 1M | 100.0% |
Amazon Bedrock | $4.40 | $22 | 1M | 99.9% |
Azure | $4.40 | $22 | 1M | 99.1% |
Google | $4.40 | $22 | 1M | 100.0% |
Google | $4.40 | $22 | 1M | 100.0% |
AnthropicOfficial | $8 | $40 | 1M | 100.0% |
Availability and prices come from OpenRouter’s public API and are refreshed daily. Uptime is the share of successful requests over the last 24 hours. Some providers run a compressed version of open models (fp8, int4), which is cheaper but can be slightly less accurate.
Use it in your code
Call Claude Opus 5.5 through OpenRouter’s OpenAI-compatible API: create a key on openrouter.ai, then run one of these examples.
curl https://openrouter.ai/api/v1/chat/completions \
-H "Authorization: Bearer $OPENROUTER_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model": "anthropic/claude-opus-5.5", "messages": [{"role": "user", "content": "Hello! What can you do?"}]}'import os
from openai import OpenAI
client = OpenAI(base_url="https://openrouter.ai/api/v1", api_key=os.environ["OPENROUTER_API_KEY"])
reply = client.chat.completions.create(
model="anthropic/claude-opus-5.5",
messages=[{"role": "user", "content": "Hello! What can you do?"}],
)
print(reply.choices[0].message.content)import OpenAI from "openai";
const client = new OpenAI({ baseURL: "https://openrouter.ai/api/v1", apiKey: process.env.OPENROUTER_API_KEY });
const reply = await client.chat.completions.create({
model: "anthropic/claude-opus-5.5",
messages: [{ role: "user", content: "Hello! What can you do?" }],
});
console.log(reply.choices[0].message.content);The same code works with every model on this site: only the model ID changes. Many labs also offer their own API and SDK.
What it costs in practice
- 1,000 chat replies$8.00
- Summarise a 100-page document$0.22
- An app with 10,000 requests a day for a month$3,600
Similar-priced alternatives
| Model | Inputi | Outputi | Contexti | |
|---|---|---|---|---|
Qwen3.8 Max PrimeAlibaba Qwen | $4 | $12 | 1M | Compare with ⇄ |
Ember-1Fireworks AI | $3 | $15 | 1M | Compare with ⇄ |
Aion 3.5Aion Labs | $3 | $6 | 256K | Compare with ⇄ |
GPT-5.6 Sol ProOpenAI | $4 | $20 | 1.1M | Compare with ⇄ |
GLM 5.3 PrimeZ.ai (Zhipu) | $2.80 | $8.80 | 1M | Compare with ⇄ |
MiMo-V2.6-Pro-UltraSpeedXiaomi | $4.35 | $8.70 | 1M | Compare with ⇄ |
News about Anthropic
See all →Frequently asked questions
- How much does Claude Opus 5.5 cost?
- Claude Opus 5.5 costs $4 per million input tokens and $20 per million output tokens through the API. For example, 1,000 chat replies of about 500 tokens in and 300 out cost around $8.00.
- What is the context window of Claude Opus 5.5?
- Claude Opus 5.5 can read up to 1,000,000 tokens in one request, about 1,875 pages of text. It can write up to 128,000 tokens in a single answer.
- Is Claude Opus 5.5 open source?
- No. Claude Opus 5.5 is a closed model: its weights are not published, so you use it through Anthropic’s own apps and API, or through cloud providers.
- Who makes Claude Opus 5.5?
- Claude Opus 5.5 is made by Anthropic. It became available through the API on September 22, 2026.
- Can Claude Opus 5.5 read images?
- Yes. Besides text, it accepts images and files such as PDFs as input.
- What are the alternatives to Claude Opus 5.5?
- Models with a similar price from other companies include Qwen3.8 Max Prime, Ember-1 and Aion 3.5. You can compare them side by side on this page.