Gemini 3.1 Pro vs Grok 4.5
Pricing & Specs

Google (Gemini) vs xAI, side by side from a live registry. Specs below, then benchmark both on your own task.

$12
Gemini 3.1 Pro output / 1M
$6
Grok 4.5 output / 1M
1.04858M / 500K
context windows

TL;DR: On a typical task (1K input + 500 output tokens), Grok 4.5 is about 1.6x cheaper than Gemini 3.1 Pro. But per-token price is not cost per result: a cheaper model that needs more tokens, retries, or hand-holding can end up more expensive on your workload. The specs below are facts; which one is better at YOUR task is measurable, not guessable.

API Pricing: Gemini 3.1 Pro vs Grok 4.5

TokensGemini 3.1 ProGrok 4.5
Input$2 / 1M$2 / 1M
Output$12 / 1M$6 / 1M
Cached input$0.2 / 1M$0.3 / 1M

What that means in practice (1K input + 500 output tokens)

1x One typical task: $0.0080 on Gemini 3.1 Pro vs $0.0050 on Grok 4.5
1K 1,000 runs: $8.00 vs $5.00
💡 Real cost depends on how verbose each model is on YOUR prompts. Benchmark to measure actual tokens, not estimates.

Specs Compared

SpecGemini 3.1 ProGrok 4.5
Context window1.04858M tokens500K tokens
Max output tokens65.536K tokens-
Input modalitiestext, image, video, audio, PDFtext, image
Knowledge cutoff--
Latency (measured)--
Reasoning modelYesYes
Tool / function callingYesYes
JSON modeYesYes
Prompt cachingYesYes

When to Choose Which

High volume on a budget: start with Grok 4.5; only pay for Gemini 3.1 Pro if the benchmark shows a quality gap that matters.
Long documents or big codebases: Gemini 3.1 Pro has the larger context window (1.04858M vs 500K tokens).
Everything else: the honest answer is to benchmark both on your actual task. Quality differences are task-specific and shift with every release.

FAQ

Which is cheaper, Gemini 3.1 Pro or Grok 4.5?

Gemini 3.1 Pro costs $2/$12 per 1M input/output tokens; Grok 4.5 costs $2/$6. On a typical task (1K input + 500 output tokens), Grok 4.5 is about 1.6x cheaper than Gemini 3.1 Pro.

Which has the bigger context window, Gemini 3.1 Pro or Grok 4.5?

Gemini 3.1 Pro has a 1.04858M-token context window; Grok 4.5 has 500K tokens.

Is Gemini 3.1 Pro better than Grok 4.5?

It depends on the task. Generic leaderboards won't tell you which one wins on YOUR workload. OpenMark lets you benchmark Gemini 3.1 Pro and Grok 4.5 head to head on your own task with real API calls, no API keys needed, free tier available.

Gemini 3.1 Pro or Grok 4.5 for YOUR Task?

Spec tables can't answer that. Run both head to head on your actual workload:
real API calls, ranked results with accuracy, cost, and latency. Free tier available.

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