Head-to-head
Gemini 3 Pro vs GPT-5.2: which AI model wins in 2026?
Gemini 3 Pro ($12/1M out (prompts ≤200K)) and GPT-5.2 ($14/1M out) are two of the most-used AI models in 2026. Across 5 community votes, Gemini 3 Pro leads with 57% approval.
Quick verdict
On Reasoning, pick Gemini 3 Pro: the arena rates it 4.5/5 against 4/5 for GPT-5.2. On budget, Gemini 3 Pro wins: it starts at $12/1M out (prompts ≤200K) versus $14/1M out for GPT-5.2.
Line-by-line comparison
Strengths and weaknesses
Gemini 3 Pro
- Topped LMArena at launch with a record 1501 Elo and scored 91.9% on GPQA Diamond, state of the art at release
- ARC-AGI-2 at 31.1%, roughly 6x Gemini 2.5 Pro (4.9%) and nearly double GPT-5.1 (17.6%) at the time
- Best-in-class multimodal understanding: 81% MMMU-Pro, 87.6% Video-MMMU, with a 1M-token context window
- Strong agentic coding: 76.2% SWE-bench Verified, 54.2% Terminal-Bench 2.0, 1487 Elo on WebDev Arena
- Undercut rivals on price at $2/$12 per 1M tokens, below Claude Sonnet-class pricing ($3/$15)
- Configurable thinking_level (low/medium/high) lets developers trade reasoning depth against latency and cost
- Overconfident hallucinations: on AA-Omniscience it gave a wrong answer 88% of the time instead of declining, vs 48% for Claude Sonnet 4.5 (the-decoder)
- Sycophancy widely reported by reviewers (Zvi Mowshowitz: 'vast intelligence with no spine'); needs tight system prompts
- Tool-calling reliability issues in agent stacks: devs reported tool outputs dumped into the chat thread and more scaffolding needed than OpenAI/Anthropic models
- Slow at high thinking level: time to first token measured around 30-60s on AI Studio despite ~130 tok/s output speed
- Retired: shut down on the Gemini API and AI Studio on March 9, 2026, with gemini-3-pro-preview now aliased to Gemini 3.1 Pro
GPT-5.2
- 80.0% SWE-bench Verified and 55.6% SWE-Bench Pro at launch, near parity with Claude Opus 4.5 (80.9%)
- GDPval: ties or beats human professionals in 70.9% of comparisons, nearly double GPT-5.1's 38.8%
- Strong science and math: 92.4% GPQA Diamond (Thinking, 93.2% Pro) and 40.3% FrontierMath, state of the art at release
- 400K context with near-perfect MRCR v2 long-context retrieval up to 256K tokens
- 30% fewer hallucinations than GPT-5.1 (error rate on real ChatGPT queries down from 8.8% to 6.2%)
- Cheaper than its successors: $1.75/$14 per 1M vs $2.50/$15 (GPT-5.4) and $5/$30 (GPT-5.5)
- Speed is the top community complaint: extended thinking reported as low as ~4 tokens/s in ChatGPT, and Pro can think for a very long time and still fail
- Headline benchmark scores were obtained at xhigh reasoning effort, which consumes far more tokens and time than default settings
- Widely criticized personality regression vs GPT-5.1: Reddit users called it 'too corporate, too safe' and 'a step backwards' for chat and writing
- Coding lags Anthropic's line in head-to-head Elo comparisons (a later Opus 4.7 analysis cited a 144 Elo gap); no audio modality, no fine-tuning
- Already superseded as of mid-2026: OpenAI recommends GPT-5.5 and GPT-5.2 no longer appears on the main API pricing page
Cast your verdict
One recommendation per tool per gladiator. It reshapes the crowd score everyone sees.
The arena’s verdict on Gemini 3 Pro
A landmark release that put Google back on top in late 2025, with a huge reasoning jump over Gemini 2.5 Pro and the best multimodal scores of its generation. As of mid-2026 there is no reason to choose it: Google shut it down on the API on March 9, 2026, and Gemini 3.1 Pro costs exactly the same while more than doubling ARC-AGI-2 performance (77.1% vs 31.1%). Teams on legacy deployments should migrate to 3.1 Pro, which the old model ID now points to anyway. Avoid it for hallucination-sensitive workloads unless you add grounding, a weakness reviewers flagged repeatedly.
The arena’s verdict on GPT-5.2
Pick GPT-5.2 over GPT-5.1 for heavy reasoning, long-context, or agentic work: it nearly doubles GPT-5.1's GDPval win rate, cuts hallucinations 30%, and handles 400K contexts reliably. In mid-2026 it is mainly a value play, priced at $1.75/$14 versus $5/$30 for GPT-5.5 while staying competent on most professional tasks. Avoid it for latency-sensitive chat and creative writing, where users found it slow and flatter than GPT-5.1. Teams that want OpenAI's current frontier should pay up for GPT-5.5 instead.
What the crowd says
On Gemini 3 Pro
“Confidently wrong is its worst mode. On AA-Omniscience it gave a wrong answer 88% of the time instead of declining. Add the sycophancy and you need a tight system prompt to trust it.”
“ARC-AGI-2 at 31% was about 6x Gemini 2.5 Pro and nearly double GPT-5.1 at the time. For visual-heavy work (81 MMMU-Pro) nothing else came close.”
“1501 Elo on LMArena at launch was deserved. Multimodal is where it kills, I feed it lecture videos and dense PDFs and it just gets it. 1M context helps.”
On GPT-5.2
“The thinking speed is brutal, I clocked something like 4 tok/s in ChatGPT on extended thinking. Pro will grind for ages and still whiff. Great scores, painful to actually use.”
“GDPval numbers are wild, it ties or beats human pros in 71% of comparisons. For science and math work (92.4 GPQA Diamond) it earned a spot in my stack.”
Keep comparing
Frequently asked questions
Is Gemini 3 Pro better than GPT-5.2?
The crowd currently sides with Gemini 3 Pro: 57% recommend it, versus 50% for GPT-5.2 (5 votes). On Reasoning, Gemini 3 Pro rates higher (4.5/5 vs 4/5). The right pick depends on your use case. The line-by-line comparison on this page breaks down pricing, key specs and arena ratings.
Which is cheaper, Gemini 3 Pro or GPT-5.2?
Gemini 3 Pro is cheaper: it starts at $12/1M out (prompts ≤200K), while GPT-5.2 starts at $14/1M out.
How much do Gemini 3 Pro and GPT-5.2 cost per 1M tokens?
Gemini 3 Pro: $2/1M in (prompts ≤200K) per 1M input tokens, $12/1M out (prompts ≤200K) per 1M output tokens. GPT-5.2: $1.75/1M in per 1M input tokens, $14/1M out per 1M output tokens.