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.
—$0.75
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.
—$4.50
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.
—$0.075
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.
—$0.375OpenAI
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
—$2.25OpenAI
—$375OpenAI list price
Benchmarks
SWE-Bench ProAgentic coding — Can the AI fix real bugs in real software? It's handed actual problems from open-source projects and has to write code that genuinely solves them. Higher is better.
77.8%54.4%
Terminal-Bench 2.0Agentic terminal coding — Can the AI work in a command-line terminal — running commands and finishing technical setup tasks the way a developer would? (Version 2.0 of the test.) Higher is better.
82%60%
Humanity's Last Exam · no toolsMultidisciplinary reasoning — Humanity's Last Exam — extremely hard expert questions across many subjects, written so you can't just look up the answer. “No tools” means the AI answers on its own. Higher is better.
56.8%28.2%
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.
64.7%41.5%
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%
OSWorld-VerifiedAgentic computer use — Can the AI actually operate a computer — clicking, typing, and using real apps — to finish tasks on its own? Higher is better.
79.6%72.1%
Overview
CompanyAnthropicOpenAI
Release dateApr 7 2026Mar 17 2026
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Claude Mythos Preview leads GPT-5.4 mini on 6 of the 6 benchmarks they both report. Only GPT-5.4 mini has a verified first-party price for an available API: $0.75 per million input tokens and $4.50 per million output tokens. No currently available pay-as-you-go API rate is tracked for Claude Mythos Preview. GPT-5.4 mini shipped 21 days before Claude Mythos Preview, so benchmark comparisons should account for the intervening progress.

Context windows are 1M (Claude Mythos Preview) vs 400k (GPT-5.4 mini).

On SWE-Bench Pro, Claude Mythos Preview leads at 77.8% vs GPT-5.4 mini at 54.4%. On Terminal-Bench 2.0, Claude Mythos Preview leads at 82% vs GPT-5.4 mini at 60%. On Humanity's Last Exam · no tools, Claude Mythos Preview leads at 56.8% vs GPT-5.4 mini at 28.2%. On Humanity's Last Exam · with tools, Claude Mythos Preview leads at 64.7% vs GPT-5.4 mini at 41.5%. On GPQA Diamond, Claude Mythos Preview leads at 94.5% vs GPT-5.4 mini at 88%. On OSWorld-Verified, Claude Mythos Preview leads at 79.6% vs GPT-5.4 mini at 72.1%.