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.
1M1.05M
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.
—$2.50
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.
—$15.00
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
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.
—$1.25OpenAI
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
—$7.50OpenAI
—$1,250OpenAI 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%57.7%
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%75.1%
CyberGymCybersecurity — Tests the AI on cybersecurity challenges — finding and exploiting software weaknesses inside a safe sandbox. Higher is better.
83.1%79%
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%39.8%
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%52.1%
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%92.8%
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%75%
Overview
CompanyAnthropicOpenAI
Release dateApr 7 2026Mar 5 2026
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Claude Mythos Preview leads GPT-5.4 on 7 of the 7 benchmarks they both report. Only GPT-5.4 has a verified first-party price for an available API: $2.50 per million input tokens and $15.00 per million output tokens. No currently available pay-as-you-go API rate is tracked for Claude Mythos Preview. GPT-5.4 shipped 33 days before Claude Mythos Preview, so benchmark comparisons should account for the intervening progress.

Context windows are 1M (Claude Mythos Preview) vs 1.05M (GPT-5.4).

On SWE-Bench Pro, Claude Mythos Preview leads at 77.8% vs GPT-5.4 at 57.7%. On Terminal-Bench 2.0, Claude Mythos Preview leads at 82% vs GPT-5.4 at 75.1%. On CyberGym, Claude Mythos Preview leads at 83.1% vs GPT-5.4 at 79%. On Humanity's Last Exam · no tools, Claude Mythos Preview leads at 56.8% vs GPT-5.4 at 39.8%. On Humanity's Last Exam · with tools, Claude Mythos Preview leads at 64.7% vs GPT-5.4 at 52.1%. On GPQA Diamond, Claude Mythos Preview leads at 94.5% vs GPT-5.4 at 92.8%. On OSWorld-Verified, Claude Mythos Preview leads at 79.6% vs GPT-5.4 at 75%.