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.
—$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.
—$120.00
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.
—$15.00OpenAI
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
—$120.00OpenAI
—$9,000OpenAI 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.
94.5%88.4%
Overview
CompanyAnthropicOpenAI
Release dateApr 7 2026Aug 7 2025
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Claude Mythos Preview leads GPT-5 Pro on 1 of the 1 benchmark they both report (GPQA Diamond). Only GPT-5 Pro has a verified first-party price for an available API: $15.00 per million input tokens and $120.00 per million output tokens. No currently available pay-as-you-go API rate is tracked for Claude Mythos Preview. GPT-5 Pro shipped 243 days before Claude Mythos Preview, so benchmark comparisons should account for the intervening progress.

Context windows are 1M (Claude Mythos Preview) vs 400k (GPT-5 Pro).

On GPQA Diamond, Claude Mythos Preview leads at 94.5% vs GPT-5 Pro at 88.4%.