Compare AI models

Specifications
ParametersThe learned values that shape how a model responds. B means billion and T means trillion. For mixture-of-experts models, the total count is larger than the number active for each token. Parameter count alone does not measure quality.
—2.8T
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.
1M1M
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.
—$3.00
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.
—$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.
—$0.30
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.
—$0.162Wafer
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
—$9.3388Relace
—$503Relace · fp4
Benchmarks
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%43.5%
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%56%
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%93.5%
CharXiv ReasoningChart reasoning — Can the AI read and reason about complex charts and figures, not just text? Higher is better.
86.1%84.8%
Overview
CompanyAnthropicMoonshot AI
Release dateApr 7 2026Jul 16 2026
AccessClosedOpen Weight
Model detailsView modelView model

Frequently asked questions

Claude Mythos Preview leads Kimi K3 on 4 of the 4 benchmarks they both report (Humanity's Last Exam, GPQA Diamond, CharXiv Reasoning). Only Kimi K3 has a verified first-party price for an available API: $3.00 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. Claude Mythos Preview shipped 100 days before Kimi K3, so benchmark comparisons should account for the intervening progress.

Context windows are 1M (Claude Mythos Preview) vs 1M (Kimi K3). Claude Mythos Preview is closed, while Kimi K3 is open weight.

On Humanity's Last Exam · no tools, Claude Mythos Preview leads at 56.8% vs Kimi K3 at 43.5%. On Humanity's Last Exam · with tools, Claude Mythos Preview leads at 64.7% vs Kimi K3 at 56%. On GPQA Diamond, Claude Mythos Preview leads at 94.5% vs Kimi K3 at 93.5%. On CharXiv Reasoning, Claude Mythos Preview leads at 86.1% vs Kimi K3 at 84.8%.