Claude Opus 4.5: pricing, context and performance

What you need to know

Released on November 24, 2025, Claude Opus 4.5 is one of the 12 Anthropic models tracked on this site. It is a closed model: you access it through an API, from Anthropic or one of the 29 providers listed on models.dev. It has a reasoning mode: it can "think" before answering, which helps with multi-step problems but uses more tokens, and therefore more money. That makes it 11 months old as of October 22, 2026.

We file it under mid-range models (34 models in this category on the site).

Benchmark results

According to results published by Epoch AI (checked on October 22, 2026), Claude Opus 4.5 has a capability index of 74.3 out of 100, computed on 5 benchmarks from our basket.

It is not among the top 30 of the weekly ranking.

• GPQA Diamond (PhD-level science questions): 86% — the best tracked model, Gemini 4 Argon, reaches 96.4%
• OTIS Mock AIME (competition mathematics problems): 86.1% — the best tracked model, GPT-5.5 Pro, reaches 100%
• FrontierMath (very hard research-level mathematics): 34.4% — the best tracked model, GPT-6 Astra, reaches 93.7%
• SWE-bench Verified (fixing real software bugs): 76.7% — the best tracked model, Claude Opus 4.7, reaches 83.5%

Technical specifications

Its context window reaches 200,000 tokens, roughly 300 pages of text at 500 words per page: enough for a long report or several contracts at once. A single answer can run to 64,000 tokens.

It accepts as input: text, image and PDF. Its knowledge stops at May 2025: beyond that, it needs web search or your documents.

It can call tools (functions, APIs) and return structured JSON output, which makes it a possible foundation for an AI agent.

What it costs

Claude Opus 4.5 costs $5 per million input tokens and $25 per million output tokens (developer's price, checked on October 22, 2026).

To put it in perspective: reading 20,000 tokens (about thirty pages) and writing 2,000 costs roughly $0.15; a thousand of those tasks, $150.

That is 5.7 times the median output price of mid-range models ($4.38).

Tokens read back from cache cost $0.50 per million, which helps an agent that keeps resending the same context.

To estimate your own budget, use the agent cost calculator.

When to choose it

Given its category, Claude Opus 4.5 is mainly aimed at a balance between quality and cost, for everyday uses that do not justify a frontier model.

Its SWE-bench Verified result (76.7%, above the median of tracked models) makes it a serious candidate for coding agents.

Before adopting it, test it on your own examples: benchmarks measure standard tasks, not your job.

What could replace it?

In the same category, the models closest to Claude Opus 4.5 are:

• Grok 4.20 (Reasoning) (xAI, index 74.6)
• GPT-5 (OpenAI, index 75.3)
• Gemini 3.6 Flash (Google DeepMind, index 73.1)
• GPT-5.1 (OpenAI, index 75.8)