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.
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
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.
70%52.1%
Overview
CompanyMoonshot AIOpenAI
Release dateOct 23 2026Mar 5 2026
AccessOpen WeightClosed
Model detailsView modelView model

Frequently asked questions

Kimi K3.1 Pro leads GPT-5.4 on 1 of the 1 benchmark they both report (Humanity's Last Exam). Only GPT-5.4 has a verified first-party API price: $2.50 per million input tokens and $15.00 per million output tokens. No pay-as-you-go API rate is tracked for Kimi K3.1 Pro. GPT-5.4 shipped 232 days before Kimi K3.1 Pro, so benchmark comparisons should account for the intervening progress.

Context windows are 1M (Kimi K3.1 Pro) vs 1.05M (GPT-5.4). Kimi K3.1 Pro is open weight, while GPT-5.4 is closed.

On Humanity's Last Exam · with tools, Kimi K3.1 Pro leads at 70% vs GPT-5.4 at 52.1%.