GPT-5 vs Grok 4

Data reconciled September 29, 2026

Short answer

GPT-5 and Grok 4 each win on different axes — neither is simply cheaper or better across the board.

Grok 4 is 4× cheaper on output.

GPT-5 holds a 1.1× larger context window.

Grok 4 returns a 2× longer answer per call.

Image input is supported only by GPT-5.

Reasoning mode is supported only by GPT-5.

Side by side

Parameter	GPT-5	Grok 4
Provider	OpenAI	xAI
Input, $ per 1M tokens	$1.25	$1.25
Output, $ per 1M tokens	$10.00	$2.50
Cache read, $ per 1M	$0.13	$0.20
Context window	272,000	256,000
Max output	128,000	256,000
Vision	yes	no
Tools	yes	yes
Reasoning	yes	no
Status	available	available

What it costs on your own workload

A price gap per million tokens says little until your volumes are plugged in: on a long fixed system prompt the winner is the model with cheap cache reads, not the one with a cheap input rate. Run GPT-5 and Grok 4 against your own numbers.

Open the cost calculator

What is deliberately absent

We do not compare answer quality and we do not reprint third-party benchmarks. We have no quality measurements of our own, and external tables go stale faster than prices while being compiled, almost always, by someone with a stake in the result. What is here is only what we reconcile ourselves every day: prices, limits and supported capabilities.

Other comparisons

Model catalog