SSyncDev

AI model comparison

Gemini 2.5 Flash vs Grok 4.20 (Reasoning)

Compare pricing, context limits, supported inputs and deployment options to choose a model for your workflow.

Gemini 2.5 Flash from Google lists 1.05M context, 65.54K maximum output, $0.30 input per 1M tokens, $2.50 output per 1M tokens. Grok 4.20 (Reasoning) from xAI lists 1M context, 30K maximum output, $1.25 input per 1M tokens, $2.50 output per 1M tokens. Compare the inputs, outputs and deployment options below to see which fits your workflow.

Side-by-sideCapabilities and practical differences

Google

Gemini 2.5 Flash

Gemini 2.5 Flash from Google: Fast Gemini workhorse for multimodal apps where latency and price matter.

Context
1.05M
Max output
65.54K
Input / 1M tokens
$0.30
Output / 1M tokens
$2.50

Accepts

  • Text input
  • Image input
  • Audio input
  • Video input
  • PDF input

Produces

  • Text output
Full model profilegithub.com ↗
VS

xAI

Grok 4.20 (Reasoning)

Grok 4.20 (Reasoning) from xAI: Reasoning Grok for document-heavy analysis and long-horizon tool use.

Context
1M
Max output
30K
Input / 1M tokens
$1.25
Output / 1M tokens
$2.50

Accepts

  • Text input
  • Image input
  • PDF input

Produces

  • Text output
Full model profilegithub.com ↗

At a glance

Key differences

Compare the available figures below, then try both models on the work you need to do.

Gemini 2.5 Flash

  • Context capacity: 1.05M
  • Maximum output: 65.54K
  • Input price: $0.30

Context capacity

Higher listed limit

Gemini 2.5 Flash:1.05M

Grok 4.20 (Reasoning):1M

Gemini 2.5 Flash

Maximum output

Higher listed limit

Gemini 2.5 Flash:65.54K

Grok 4.20 (Reasoning):30K

Gemini 2.5 Flash

Input price

Lower listed token rate

Gemini 2.5 Flash:$0.30

Grok 4.20 (Reasoning):$1.25

Gemini 2.5 Flash

Output price

Lower listed token rate

Gemini 2.5 Flash:$2.50

Grok 4.20 (Reasoning):$2.50

Same value

Specifications

Pricing, limits and capabilities

Specifications for Gemini 2.5 Flash and Grok 4.20 (Reasoning). Higher limits and lower prices describe these figures only.
SpecificationGemini 2.5 FlashGrok 4.20 (Reasoning)
ProviderGooglexAI
Listed pricing routeGooglexAI
Model familygemini-flashgrok
Accepted inputstext, image, audio, video, pdftext, image, pdf
Produced outputstexttext
Context window1.05MHigher1M
Max output65.54KHigher30K
Input price / 1M$0.30Lower$1.25
Output price / 1M$2.50$2.50
Reasoning modeDocumentedDocumented
Tool callingDocumentedDocumented
Image inputDocumentedDocumented
Audio inputDocumentedNot documented
Structured outputDocumentedDocumented
LicenseProprietaryProprietary

Workload guidance

Which model should you choose?

Consider Gemini 2.5 Flash if you need larger context or larger maximum output or a lower listed input rate. Test both on the same representative examples and judge the output against your acceptance criteria. Include tool failures, retries and the time to a completed task.

Documentation and model profiles

Explore each model’s features, API requirements and licence terms in the sources below.

Questions people ask

It brings together documented inputs and outputs, token limits, deployment terms and available pricing. When both models have source-linked, verified results on a shared benchmark, those results are shown with their individual sources. The comparison is a starting point for evaluating your own workload.

Compare a different pair

Search by model or provider to explore another comparison.

Open model comparison