Head-to-head
Gemini 3 Pro vs Grok 4.3: which AI model wins in 2026?
Gemini 3 Pro ($12/1M out (prompts ≤200K)) and Grok 4.3 ($2.50/1M out) are two of the most-used AI models in 2026. Across 3 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 Grok 4.3. On budget, Grok 4.3 wins: it starts at $2.50/1M out versus $12/1M out (prompts ≤200K) for Gemini 3 Pro.
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
Grok 4.3
- Aggressive pricing: $1.25/$2.50 per 1M tokens, 58% cheaper input and 83% cheaper output than Grok 4, undercutting GPT-5.5 and Gemini 3.1 Pro
- Major agentic leap: +321 Elo on GDPval-AA versus Grok 4.20, with strong tool calling and instruction following
- Cached input at $0.20/1M (84% discount), a big saver for repeated agent loops
- Configurable reasoning effort (none/low/medium/high) in one model at one price, no routing between fast and deep variants
- Praised on HN for natural, concise tone and token-dense outputs that lower real-world costs
- Solid throughput around 130 output tokens/sec (Artificial Analysis)
- Coding reasoning judged 'not competitive with the big April releases' by HN developers; intelligence frontier barely moved since Grok 4
- Non-hallucination score dropped 8 points vs Grok 4.20 on AA-Omniscience; 4.20 remains xAI's safer pick for precision-critical domains
- High time to first token (~13s at high reasoning effort per Artificial Analysis), painful for interactive apps
- Context window shrank to 1M from Grok 4.20's 2M
- Recurring trust and safety complaints (harmful content reports, inconsistent behavior) and no MCP/connected-apps support in the consumer app
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 Grok 4.3
Pick Grok 4.3 if you run agentic or high-volume pipelines where cost per call dominates: it delivers near-frontier reasoning and a big tool-calling jump over Grok 4.20 at a fraction of GPT-5.5 or Gemini 3.1 Pro pricing. Skip it if coding precision is your priority, as developers still rank Claude and the big April releases ahead. Also stay on Grok 4.20 if you need its 2M context or its better non-hallucination score for legal, medical, or compliance work. Latency-sensitive apps should test the ~13s time to first token before committing.
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 Grok 4.3
No verdicts yet. Be the first to speak.
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Frequently asked questions
Is Gemini 3 Pro better than Grok 4.3?
The crowd currently sides with Gemini 3 Pro: 57% recommend it, versus 50% for Grok 4.3 (3 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 Grok 4.3?
Grok 4.3 is cheaper: it starts at $2.50/1M out, while Gemini 3 Pro starts at $12/1M out (prompts ≤200K).
How much do Gemini 3 Pro and Grok 4.3 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. Grok 4.3: $1.25/1M in per 1M input tokens, $2.50/1M out per 1M output tokens.