Compare AI models

Specifications
Context windowHow much text the model can hold in mind at once — your question, any documents you attach, the conversation so far, and its own reply. Go past it and the earliest part falls out of view.
—128k
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.
$1.25$15.00
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.
$10.00$60.00
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.
$0.125$7.50
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.
$0.625OpenAI—
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
$5.00OpenAI—
$750OpenAI list price$6,000OpenAI list price
Benchmarks
GPQA DiamondScience — Graduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better.
88.1%73.3%
Overview
CompanyOpenAIOpenAI
Release dateNov 12 2025Sep 12 2024
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

GPT-5.1 leads o1-preview on 1 of the 1 benchmark they both report (GPQA Diamond). GPT-5.1 is cheaper on both input and output: $1.25 vs $15.00 per million input tokens, and $10.00 vs $60.00 per million output tokens. o1-preview shipped 426 days before GPT-5.1, 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 GPQA Diamond, GPT-5.1 leads at 88.1% vs o1-preview at 73.3%.