⚔ AI Comparison

Gemini 3.1 Pro vs GPT-5.5: Google's Multimodal Giant Takes On OpenAI's Reasoning Powerhouse

Gemini 3.1 Pro vs GPT-5.5 Last tested May 2026
🏆 Overall Winner
Gemini 3.1 Pro
Gemini 3.1 Pro edges out GPT-5.5 on overall value — it matches or beats GPT-5.5 on most benchmarks, dominates multimodal tasks (82.8 vs 70.4 avg), supports native voice and video processing, and costs 60% less per token. GPT-5.5 fights back with stronger agentic coding workflows and faster task completion, but at $5/$30 per million tokens versus Gemini's $2/$12, the price gap is hard to justify unless you specifically need OpenAI's agentic ecosystem. For most teams, Gemini 3.1 Pro delivers frontier-level intelligence at mid-tier pricing.

Performance Scores

Gemini 3.1 Pro
8.5
GPT-5.5
8.0

Strengths & Weaknesses

Gemini 3.1 Pro
  • Multimodal dominance — scores 82.8 avg on multimodal/grounded tasks vs GPT-5.5's 70.4, with native voice and video processing support
  • 2.5x cheaper — $2 input / $12 output per 1M tokens vs GPT-5.5's $5/$30, with cached input at just $0.20/1M tokens
  • Novel reasoning — 77.1% on ARC-AGI-2 (problems never seen before) crushes GPT-5.5's 52.9%, showing stronger generalization
  • GPQA Diamond leader at 94.3% — best-in-class graduate-level science reasoning
  • SWE-Bench 80.6% — strong real-world software engineering performance
  • 1M token context window with voice/video input — process hour-long videos or entire codebases in a single prompt
  • Free tier includes daily Gemini 3.1 Pro access via Google AI subscription
  • Advanced math lags GPT-5.5 by ~18 points on FrontierMath benchmark
  • Slower on agentic multi-step coding tasks — makes more tool calls to complete equivalent work
  • Knowledge cutoff (Jan 31, 2025) is 10 months older than GPT-5.5's (Dec 1, 2025)
  • Higher cost above 200K context — input jumps to $4/1M tokens, output to $18/1M tokens
  • Ecosystem lock-in to Google Cloud for enterprise features
GPT-5.5
  • Agentic coding excellence — fewer tool calls and faster task completion for complex multi-step workflows
  • FrontierMath leader — 18-point advantage over Gemini 3.1 Pro on advanced mathematics
  • HumanEval 93.1% — top-tier code generation accuracy
  • MMLU 92.4% — strongest general knowledge benchmark score
  • Newer knowledge cutoff (Dec 1, 2025) — 10 months fresher than Gemini 3.1 Pro
  • More token-efficient than GPT-5.4 — delivers better results with fewer tokens for most tasks
  • Deep integration with OpenAI ecosystem (Codex, Operator, ChatGPT plugins)
  • 2.5x more expensive — $5/$30 per 1M tokens makes high-volume usage costly
  • Weaker multimodal performance — 70.4 avg vs Gemini's 82.8 on grounded/multimodal tasks
  • No native voice or video input processing
  • ARC-AGI-2 score of 52.9% suggests weaker generalization on truly novel problems
  • Slightly smaller effective context (922K input + 128K output vs Gemini's full 1M)

Which Should You Choose?

Choose Gemini 3.1 Pro if…
You need multimodal processing (video, images, audio analysis), you're budget-conscious and processing high token volumes, you want the largest effective context window for document-heavy workflows, or you need native voice/video input. Gemini 3.1 Pro gives you 90%+ of GPT-5.5's intelligence at 40% of the cost.
Choose GPT-5.5 if…
You're building agentic coding workflows where speed and fewer tool calls matter, you need advanced mathematical reasoning, you want the freshest knowledge cutoff, or you're already deep in the OpenAI ecosystem (Codex, Operator, ChatGPT plugins). The premium pricing buys you the best agentic execution in the market.

Pricing

Gemini 3.1 Pro
API: $2.00 input / $12.00 output per 1M tokens (under 200K context). $4.00/$18.00 above 200K. Cached input: $0.20/1M. Consumer: Google AI Pro $19.99/mo, AI Ultra $99.99/mo. Free tier includes daily Gemini 3.1 Pro access.
GPT-5.5
API: $5.00 input / $30.00 output per 1M tokens. Cached input: $0.50/1M. Batch/Flex pricing: $2.50/$15.00. GPT-5.5 Pro: $30.00 input / $180.00 output. Consumer: ChatGPT Plus $20/mo, Pro $200/mo.

Sample Prompt Tests

Test 1 Tie wins

"Analyze this 45-minute product demo video and create a competitive intelligence brief with timestamps, feature comparisons, and pricing insights"

Gemini 3.1 Pro

Gemini 3.1 Pro processes the full video natively, generating a structured brief with accurate timestamps (e.g., '12:34 — new API rate limiting feature'), a feature comparison matrix against 3 competitors, and extracted pricing tiers. The multimodal understanding catches visual UI elements the transcript alone would miss.

GPT-5.5

GPT-5.5 cannot process video directly. Working from a transcript, it produces a solid competitive brief with logical feature groupings and pricing analysis, but misses visual-only information like UI screenshots, demo flows, and on-screen pricing tables shown but not spoken.

Why Tie wins: Native video processing gives Gemini a structural advantage — it captures visual information that transcript-only analysis fundamentally cannot access.

Test 2 Tie wins

"Debug this 2,000-line Python microservice: find the race condition causing intermittent 500 errors under load, then write a fix with tests"

Gemini 3.1 Pro

Gemini 3.1 Pro identifies the race condition in the connection pool manager (line 847) where two threads can grab the same connection object. Proposes a threading.Lock fix and writes 3 test cases. Takes two rounds of tool calls to verify the fix.

GPT-5.5

GPT-5.5 pinpoints the same race condition on the first pass, implements an asyncio.Lock fix (more appropriate for the async codebase), writes 5 test cases including a stress test, and validates the fix — all in a single agentic loop with fewer tool calls.

Why Tie wins: GPT-5.5's agentic coding workflow is more efficient — it identified the async context correctly, chose the right concurrency primitive, wrote more comprehensive tests, and completed the task in fewer steps.

Bottom Line

Our Verdict This is the closest head-to-head matchup in the current AI landscape. Gemini 3.1 Pro wins on value — it's 2.5x cheaper, leads on multimodal tasks, and matches GPT-5.5 on most benchmarks. GPT-5.5 wins on agentic coding speed and advanced math. For most users and use cases, Gemini 3.1 Pro is the smarter buy. But if you're building complex AI agents or need cutting-edge math reasoning, GPT-5.5 justifies its premium.

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