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 · base tier
Input priceWhat you pay for everything you send the model — your question, plus any documents or earlier conversation you include with it.
$4.00$1.25
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$2.50
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$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$375SpaceXSI list price
Benchmarks
BullshitBench v2Nonsense detection — Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better.
63%56%
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%53.3%
Overview
CompanyAnthropicSpaceXSI
Release dateSep 22 2026Feb 17 2026
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Claude Opus 5.5 leads Grok 4.20 Beta on 2 of the 2 benchmarks they both report (BullshitBench v2, ARC-AGI-2). Grok 4.20 Beta is cheaper on both input and output: $1.25 vs $4.00 per million input tokens, and $2.50 vs $20.00 per million output tokens. Figures are base-tier rates. Grok 4.20 Beta shipped 217 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 BullshitBench v2, Claude Opus 5.5 leads at 63% vs Grok 4.20 Beta at 56%. On ARC-AGI-2, Claude Opus 5.5 leads at 91.7% vs Grok 4.20 Beta at 53.3%.