Compare AI models

Specifications
Context windowHow much information the model can work with in one request, measured in tokens — pieces of words or other data. This includes your question, attachments, conversation and reply. Limits can vary by model variant and provider.
1M—
API pricingUSD per 1M tokens · lower wins
Input priceWhat you pay for everything you send the model — your question, plus any documents or earlier conversation you include with it.
$4.00—
Output priceWhat you pay for the text the model writes back. It is normally the dearer half: producing an answer costs more than reading one.
$20.00—
Cached input priceA reduced rate for text you send over and over. If every request starts with the same instructions or the same document, the provider keeps a copy ready and charges less to read it again.
$0.20—
Cheapest inputLowest input rate across every provider on OpenRouter, the lab included. The cheapest endpoint may run a quantised build or a shorter context — see "Available from" on the model page.
$4.00Amazon Bedrock—
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
$20.00Amazon Bedrock—
$1,800Anthropic list price—
Benchmarks
Humanity's Last Exam · with toolsMultidisciplinary reasoning — Humanity's Last Exam — extremely hard expert questions across many subjects. “With tools” means the AI is allowed to search the web or run code while answering. Higher is better.
67.7%50.4%
ARC-AGI-2Abstract reasoning — Puzzle-style tests of abstract reasoning and pattern-finding — the kind of thing people find easy but AIs often struggle with. Higher is better.
91.7%42.5%
Overview
CompanyAnthropicMeta
Release dateSep 22 2026Apr 8 2026
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Claude Opus 5.5 leads Muse Spark on 2 of the 2 benchmarks they both report (Humanity's Last Exam, ARC-AGI-2). Only Claude Opus 5.5 has a verified first-party price for an available API: $4.00 per million input tokens and $20.00 per million output tokens. No currently available pay-as-you-go API rate is tracked for Muse Spark. Muse Spark shipped 167 days before Claude Opus 5.5, so benchmark comparisons should account for the intervening progress.

Published specifications for these two models are limited — see each model page for the latest details.

On Humanity's Last Exam · with tools, Claude Opus 5.5 leads at 67.7% vs Muse Spark at 50.4%. On ARC-AGI-2, Claude Opus 5.5 leads at 91.7% vs Muse Spark at 42.5%.