Head-to-head
GPT-5.2 vs Gemini 3.5 Flash: which AI model wins in 2026?
GPT-5.2 ($14/1M out) and Gemini 3.5 Flash ($9.00/1M out) are two of the most-used AI models in 2026. Across 2 community votes, GPT-5.2 leads with 50% approval.
Quick verdict
On Reasoning, pick GPT-5.2: the arena rates it 4/5 against 3.5/5 for Gemini 3.5 Flash. On budget, Gemini 3.5 Flash wins: it starts at $9.00/1M out versus $14/1M out for GPT-5.2.
Line-by-line comparison
Strengths and weaknesses
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- Already superseded as of mid-2026: OpenAI recommends GPT-5.5 and GPT-5.2 no longer appears on the main API pricing page
Gemini 3.5 Flash
- Beats Gemini 3.1 Pro on agentic benchmarks: 76.2% Terminal-Bench 2.1, 1656 Elo GDPval-AA (vs 1314 for 3.1 Pro), 83.6% MCP Atlas
- Artificial Analysis Intelligence Index 50 at high thinking effort, ranking #10 of 170 tracked models
- Very fast generation (~185 output tokens/sec per Artificial Analysis); Google claims 4x faster output than other frontier models
- 1M-token context window (1,048,576) with multimodal input: text, image, audio, video, PDF
- 25% cheaper than Gemini 3.1 Pro ($1.50/$9 vs $2/$12) while outperforming it on production agent workloads
- Adjustable thinking effort (minimal/low/medium/high) plus 50% batch discount and $0.15/1M context caching
- 3x price increase over Gemini 3 Flash ($0.50/$3.00) and 5-6x over 2.5 Flash; HN devs saw it as Google probing price tolerance
- Over-eager and verbose: devs report it ignores completion criteria and embellishes beyond instructions (compared to Claude's 'Sonnet 3.7 moment')
- Reliability complaints on Flash serving: developers report frequent 503 errors during peak periods
- Weaker on long-horizon agentic tasks with arbitrary tool availability, a recurring theme devs report with Google models
- High time-to-first-token (~23s at high thinking effort per Artificial Analysis), poor fit for latency-sensitive chat
Cast your verdict
One recommendation per tool per gladiator. It reshapes the crowd score everyone sees.
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.
The arena’s verdict on Gemini 3.5 Flash
Pick Gemini 3.5 Flash if you run agentic coding or high-volume multimodal pipelines and want near-Pro quality at 4x the speed: it actually beats Gemini 3.1 Pro on Terminal-Bench and GDPval while costing 25% less. Avoid it if you used the Flash line as a budget tier, since it costs 3x its predecessor Gemini 3 Flash, which remains the cheap option at $0.50/$3.00. Also skip it for latency-sensitive chat at high thinking effort (~23s to first token) or strict, no-embellishment output where its verbosity works against you.
What the crowd says
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.”
On Gemini 3.5 Flash
No verdicts yet. Be the first to speak.
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Frequently asked questions
Is GPT-5.2 better than Gemini 3.5 Flash?
On Reasoning, GPT-5.2 rates higher (4/5 vs 3.5/5). 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, GPT-5.2 or Gemini 3.5 Flash?
Gemini 3.5 Flash is cheaper: it starts at $9.00/1M out, while GPT-5.2 starts at $14/1M out.
How much do GPT-5.2 and Gemini 3.5 Flash cost per 1M tokens?
GPT-5.2: $1.75/1M in per 1M input tokens, $14/1M out per 1M output tokens. Gemini 3.5 Flash: $1.50/1M in per 1M input tokens, $9.00/1M out per 1M output tokens.