Compare / head-to-head
Gemini 3 Flash Previewvs
GPT-5.1-Codex
Gemini 3 Flash Preview leads 2 of 3 shared benchmarks. Gemini 3 Flash Preview has the larger context window (1.0M tokens).
Benchmarks from cited public sources; pricing from official pages; status from official provider feeds.
Shared benchmarks
2 – 1
Gemini 3 Flash Preview leads
Cheaper per token
—
list price, input + output
Larger context
Gemini 3 Flash Preview
1.0M tokens
Providers
2 providers
Google · OpenAI
Gemini 3 Flash Preview
Google · released 2025-12-17
textvisionaudio
- Context
- 1.0M
- Max out
- 66K
- Input /1M
- —
- Output /1M
- —
- Cached /1M
- —
- Scores
- 34 · 12 core
GPT-5.1-Codex
OpenAI · released 2025-11-13
textvision
Quality
Benchmark matrix
3 shared · 23 only Gemini 3 Flash Preview · 1 only GPT-5.1-Codex| Benchmark | Gemini 3 Flash Preview | GPT-5.1-Codex | Δ | Edge |
|---|---|---|---|---|
| Reported by both · 3 | ||||
| SWE-bench Verified | 78% ↗ | 73.7% ↗ | +4.3 pt | Gemini 3 Flash Preview |
| LMArena WebDev (LMArena) | 1438.9 ↗ | 1337.1 ↗ | +101.8 | Gemini 3 Flash Preview |
| Terminal-Bench 2.0 | 47.6% ↗ | 52.8% ↗ | -5.2 pt | GPT-5.1-Codex |
| Only Gemini 3 Flash Preview reports · 23 | ||||
| GPQA Diamond | 90.4% ↗ | not reported | — | — |
| AIME 2025 | 95.2% ↗ | not reported | — | — |
| Humanity's Last Exam (no tools) | 33.7% ↗ | not reported | — | — |
| LMArena Elo | 1472.7 ↗ | not reported | — | — |
| BALROG (BALROG) | 48.1% ↗ | not reported | — | — |
| Chess Puzzles (Epoch AI run) | 40% ↗epoch run | not reported | — | — |
| FrontierMath Tier 4 v2 (Epoch AI run) | 17.1% ↗epoch run | not reported | — | — |
| FrontierMath Tiers 1-3 v2 (Epoch AI run) | 51.2% ↗epoch run | not reported | — | — |
| GSO Opt@1 (GSO) | 7.8% ↗ | not reported | — | — |
| LMArena Vision (LMArena) | 1272.9 ↗ | not reported | — | — |
| MMMU-Pro | 81.2% ↗ | not reported | — | — |
| Mystery Game Puzzles (Epoch AI run) | 26% ↗epoch run | not reported | — | — |
| OTIS Mock AIME 2024-2025 (Epoch AI run) | 95.6% ↗epoch run | not reported | — | — |
| SAGE (Vals AI) | 51.8% ↗ | not reported | — | — |
| SimpleBench (SimpleBench) | 61.1% ↗ | not reported | — | — |
| SimpleQA Verified | 68.7% ↗ | not reported | — | — |
| SWE-bench Verified (Epoch AI run) | 75.4% ↗epoch run | not reported | — | — |
| tau2-bench Airline (Sierra) | 82.5% ↗ | not reported | — | — |
| tau2-bench Banking Knowledge (Sierra) | 27.3% ↗ | not reported | — | — |
| tau2-bench Retail (Sierra) | 76.8% ↗ | not reported | — | — |
| tau2-bench Telecom (Sierra) | 91.2% ↗ | not reported | — | — |
| Vending-Bench 2 (Andon Labs) | 3634.72 ↗ | not reported | — | — |
| WeirdML (Håvard Tveit Ihle) | 61.6% ↗ | not reported | — | — |
| Only GPT-5.1-Codex reports · 1 | ||||
| SWE-Lancer IC SWE | not reported | 66.3% ↗ | — | — |
Scores tagged "epoch" or "matharena" are independent runs, used only where the lab has not published its own; ⚠ marks rows MathArena flags as released after the competition. Higher is better on every row. Δ is Gemini 3 Flash Preview minus GPT-5.1-Codex in the benchmark's own unit. "Not reported" means the lab has not published that figure; it is not a zero. ↗ opens the source.
Specs & pricing
Side by side
Official pricing pages and model cards| Spec | Gemini 3 Flash Preview | GPT-5.1-Codex | Edge |
|---|---|---|---|
| Context window | 1.0M tokens | 400K tokens | Gemini 3 Flash Preview |
| Max output | 66K tokens | 128K tokens | GPT-5.1-Codex |
| Input price / 1M | — | $1.25 ↗ | — |
| Output price / 1M | — | $10 ↗ | — |
| Cached input / 1M | — | $0.125 ↗ | — |
| Input + output / 1M Lower is cheaper. List prices; batch, tool and regional fees excluded. | — | $11.25 | — |
| Modalities | text · vision · audio | text · vision | Gemini 3 Flash Preview |
| Released | 2025-12-17 | 2025-11-13 | — |
| Cited benchmark scores | 34 | 4 | — |
Reliability
Provider status
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GPT-5.1-Codex vs …
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Which one wins on your data?
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