All Anthropic models

Claude Sonnet 4.5

Anthropic · released September 2025

Claude Sonnet 4.5 is a Anthropic model with a 1M token context window — about 1,400 pages of text. It reads Text, Images, and Files and replies in Text. It can show its reasoning before it answers.

$3.45

input / 1M tokens

$17.25

output / 1M tokens

1M

context — about 1,400 pages

3.1¢

a client proposal

Pricing

Input
$3.45 per million tokens
Output
$17.25 per million tokens
Cached input
$0.345 per million tokens
Cache writes
$4.31 per million tokens
Web search
1.1¢ per search
Long-context rate (over 200K)
$6.90 in · $25.88 out, per million tokens

Billed from your Alyph wallet. Prices can change when the provider changes theirs — last checked August 9, 2026.

The numbers

Provider
Anthropic
Released
September 2025 (2025-09-29)
Context window
1M tokens — about 1,400 pages
Max output
64K tokens per reply
Input
Text, Images, and Files
Output
Text
Reasoning
Shows its thinking before answering
Knowledge cutoff
2025-01-31

Cost vs Token Amount

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80% Input20% Output
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Claude Sonnet 4.5

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What a task costs

2K tokens in · 500 tokens out.

Claude Sonnet 4.5

Anthropic

1.6¢

for this task

44% input · 56% output

Full pricing →

Your $5 welcome credit covers about 322 of these.

Compare Claude Sonnet 4.5

Closest in price on a typical task:

Claude Sonnet 4.5 vs Claude Sonnet 4 →Claude Sonnet 4.5 vs Claude Sonnet 4.6 →Claude Sonnet 4.5 vs Kimi K3 →Claude Sonnet 4.5 vs Sonar Pro →Any other combination →

Questions, answered

How much does Claude Sonnet 4.5 cost on Alyph?

Claude Sonnet 4.5 costs $3.45 per million input tokens and $17.25 per million output tokens on Alyph. A typical task — 5K tokens in, 800 out — works out to about 3.1¢. Billed from your Alyph wallet, with hard spending limits. Prices can change when the provider changes theirs; this page was last checked on August 9, 2026.

What is Claude Sonnet 4.5's context window?

1M tokens — about 1,400 pages. Replies can be up to 64K tokens long. Prompts longer than 200K tokens are billed at the long-context rate.

Can Claude Sonnet 4.5 read images and files?

Claude Sonnet 4.5 reads Text, Images, and Files. Drop a file onto the canvas and it becomes part of the context — the only limit is the context window.

Does Claude Sonnet 4.5 show its reasoning?

Yes. Claude Sonnet 4.5 can expose its thinking before the final answer, so you can watch how it got there.

Test Claude Sonnet 4.5 against Claude Sonnet 4

One prompt, both models at the same time, the better answer wins. Free to start, with $5 of credit.

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