Gemini 2.5 Flash vs Grok 4.20

Gemini 2.5 Flash versus Grok 4.20 specifications and price.
metric	Gemini 2.5 Flash	Grok 4.20
Input / 1M	$0.30	$1.25
Output / 1M	$2.50	$2.50
Context	1.0M	2M
Cost @ typical workload	$340/mo	$625/mo
Modality	text + image + audio + video	text + image
Price source	list	list
Provider	Google	xAI

Which should you pick?

On a typical workload, Gemini 2.5 Flash costs $340/mo against Grok 4.20's $625/mo — roughly 1.8× cheaper. But the ranking depends on your output-to-input ratio: output is the pricier direction for both, so an output-heavy job (code generation, long answers) widens the gap while an input-heavy one (summarization, retrieval) narrows it. If you need to fit more in a single prompt, Grok 4.20 has the larger 2M-token window (~3,000 pages).

These are list and routed market prices, not measured outcomes. Two models at the same rate can still cost different amounts to finish the same task, because verbose or reasoning-heavy models emit more tokens. That gap is exactly what measured cost-per-task captures.

Frequently asked questions

Is Gemini 2.5 Flash or Grok 4.20 cheaper?

For a typical workload (1,500 input + 500 output tokens × 200,000 requests/month), Gemini 2.5 Flash costs $340/mo versus $625/mo for Grok 4.20 — about 1.8× less. Because output is priced higher than input, the winner can flip if your workload writes much more or less than this; check your own numbers in the calculator.

What's the main difference between Gemini 2.5 Flash and Grok 4.20?

On price, Gemini 2.5 Flash is $0.30/$2.50 per 1M (in/out) and Grok 4.20 is $1.25/$2.50. Grok 4.20 has the larger context window at 2M tokens.

More comparisons

Gemini 2.5 Flash and Grok 4.20 — full specs and price history.
API cost calculator — compare on your own workload.
All comparisons — the full head-to-head index.