Gemini 3.1 Pro Preview vs Mercury 2

API pricing, context window and capabilities for Gemini 3.1 Pro Preview and Mercury 2, side by side. Prices are the cheapest serving route per 1M tokens, verified against LiteLLM and OpenRouter.

Verdict

computed from the published numbers

Gemini 3.1 Pro Preview wins on intelligence and on context window. Mercury 2 wins on price. Benchmark data is unavailable for one or both models.

Price
Mercury 2
Coding
Not called
Intelligence
Gemini 3.1 Pro Preview
Context window
Gemini 3.1 Pro Preview

Key takeaways

who wins on what, from the published numbers

Gemini 3.1 Pro Preview wins

  • Larger context window (1M vs 128K)
  • Higher max output (66K vs 50K)
  • More serving providers (4 vs 1)
  • Supports vision
  • Has reasoning mode
  • Supports audio
  • Has web search

Mercury 2 wins

  • Cheaper input ($2.00 vs $0.25 /1M)
  • Cheaper output ($12.00 vs $0.75 /1M)
Cheaper overall
Mercury 2
$0.25 + $0.75 /1M
Larger context
Gemini 3.1 Pro Preview
1M
More providers
Gemini 3.1 Pro Preview
4 providers

Pricing & specs

cheapest serving route · per 1M tokens
Gemini 3.1 Pro PreviewMercury 2
Input $/1M$2.00 $0.25 best
Output $/1M$12.00 $0.75 best
Context window1M best128K
Max output66K best50K
Serving providers4 best1
Released2026-02-19 2026-02-24

Benchmarks

Artificial Analysis indices, side by side
Gemini 3.1 Pro PreviewMercury 2
Intelligence46.5 best25.3
Coding68.8 Not available
GPQA Diamond94% best77%
Output speed154 t/s 602 t/s best
Latency (TTFT)34.98s 2.73s best

Cost calculator

choose a serving route for each side
Input tokens / month
Output tokens / month
Gemini 3.1 Pro Preview
via Vertex AI
$22
Mercury 2
via Inception
$2.00

Capabilities

feature support, side by side
FeatureGemini 3.1 Pro PreviewMercury 2
Vision
Tool use
Reasoning
Audio
Prompt caching
Structured output
Web search

Related comparisons

Frequently asked questions

Which is cheaper, Gemini 3.1 Pro Preview or Mercury 2?
Mercury 2 is cheaper for input ($2.00 vs $0.25 per 1M tokens). Mercury 2 is cheaper for output ($12.00 vs $0.75 per 1M tokens).
What is the context window difference between Gemini 3.1 Pro Preview and Mercury 2?
Gemini 3.1 Pro Preview has a 1M-token context window and Mercury 2 has 128K tokens, so Gemini 3.1 Pro Preview can take a larger prompt.
How do Gemini 3.1 Pro Preview and Mercury 2 compare on benchmarks?
On the tracked Artificial Analysis indices, Gemini 3.1 Pro Preview leads on intelligence.
Pricing verified against LiteLLM + OpenRouter + provider pages · refreshed daily

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