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.
1M400k
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.
$10.00$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.
$50.00$10.00
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.
$0.25$0.125
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.
$10.00Amazon Bedrock$1.25Azure
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
$50.00Amazon Bedrock$10.00Azure
$4,500Anthropic list price$750OpenAI 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.
77%21%
Overview
CompanyAnthropicOpenAI
Release dateSep 1 2026Aug 7 2025
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Claude Fable 5.1 leads GPT-5 on 1 of the 1 benchmark they both report (BullshitBench v2). GPT-5 is cheaper on both input and output: $1.25 vs $10.00 per million input tokens, and $10.00 vs $50.00 per million output tokens. GPT-5 shipped 390 days before Claude Fable 5.1, so benchmark comparisons should account for the intervening progress.

Context windows are 1M (Claude Fable 5.1) vs 400k (GPT-5).

On BullshitBench v2, Claude Fable 5.1 leads at 77% vs GPT-5 at 21%.