Compare AI models

Specifications
Context windowHow much text the model can hold in mind at once — your question, any documents you attach, the conversation so far, and its own reply. Go past it and the earliest part falls out of view.
—1.05M
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.
—$5.00
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.
—$30.00
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.
—$0.50
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.
$0.15DeepSeek$2.50OpenAI
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
$0.60DeepSeek$15.00OpenAI
$60.00DeepSeek$2,500OpenAI list price
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.
42.6%41.4%
Overview
CompanyDeepSeekOpenAI
Release dateOct 17 2026Apr 23 2026
AccessOpen WeightClosed
Model detailsView modelView model

Frequently asked questions

DeepSeek-V4.1-Flash-1017 leads GPT-5.5 on 1 of the 1 benchmark they both report (Humanity's Last Exam). Only GPT-5.5 has a verified first-party API price: $5.00 per million input tokens and $30.00 per million output tokens. No pay-as-you-go API rate is tracked for DeepSeek-V4.1-Flash-1017. GPT-5.5 shipped 177 days before DeepSeek-V4.1-Flash-1017, so benchmark comparisons should account for the intervening progress.

DeepSeek-V4.1-Flash-1017 is open weight, while GPT-5.5 is closed.

On Humanity's Last Exam · no tools, DeepSeek-V4.1-Flash-1017 leads at 42.6% vs GPT-5.5 at 41.4%.