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.
1.05M256k
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.
$30.00—
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.
$180.00—
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.
$15.00OpenAI—
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
$90.00OpenAI—
$15,000OpenAI list price—
These models have no shared benchmark scores.
Overview
CompanyOpenAISpaceXSI
Release dateApr 23 2026Jul 9 2025
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

GPT-5.5-Pro and Grok 4 don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Only GPT-5.5-Pro has a verified first-party API price: $30.00 per million input tokens and $180.00 per million output tokens. No pay-as-you-go API rate is tracked for Grok 4. Grok 4 shipped 288 days before GPT-5.5-Pro, so benchmark comparisons should account for the intervening progress.

Context windows are 1.05M (GPT-5.5-Pro) vs 256k (Grok 4).

Direct benchmark comparisons are unavailable — GPT-5.5-Pro and Grok 4 don't publish scores on any of the same benchmarks.