Gemini 3.1 Pro vs Gemini 3.5 Flash
Benchmark Performance
Available Benchmarks
| Benchmark | Gemini 3.1 Pro | Gemini 3.5 Flash |
|---|---|---|
| LMArena Agent Arenaagent-2026-08-31-011508720696 · outcome_score · statistical tie | -3.13100% of row best · score · Gemini 3.1 Pro Preview; 95% CI [-4.00806078, -2.24630473]; sessions 83248; observations 2709356; rank 40 | -4.0799% of row best · score · Gemini 3.5 Flash (Medium); 95% CI [-5.53391359, -2.59876989]; sessions 13762; observations 564442; rank 44 |
| LMArena Document Arenadocument-2026-07-30-011508720696 · arena_rating · leader | 1,445.3299% of row best · rating · gemini-3.1-pro-preview; 95% CI [1439.35538449, 1451.29339146]; votes 45162; rank 23 | 1,464.65100% of row best · rating · gemini-3.5-flash-medium; 95% CI [1454.40953837, 1474.88391002]; votes 3689; rank 17 |
| LMArena Text Arenatext-2026-09-01-011508720696 · arena_rating · statistical tie | 1,480.10100% of row best · rating · gemini-3.1-pro-preview; 95% CI [1476.89767236, 1483.30025658]; votes 102763; rank 11 | 1,475.66100% of row best · rating · gemini-3.5-flash-medium; 95% CI [1471.01636052, 1480.30978904]; votes 32274; rank 17 |
| LMArena Vision Arenavision-2026-08-27-011508720696 · arena_rating · statistical tie | 1,295.3999% of row best · rating · gemini-3.1-pro-preview; 95% CI [1289.75236576, 1301.03738662]; votes 39412; rank 17 | 1,306.20100% of row best · rating · gemini-3.5-flash-medium; 95% CI [1298.00721122, 1314.38427947]; votes 8261; rank 10 |
| LiveBench2026-06-25 · overall · leader | 81.66100% of row best · percent · gemini-3.1-pro-preview-high · 13,380 output tokens / case | 78.8497% of row best · percent · gemini-3.5-flash-high · 15,522 output tokens / case |
| ToneBench2026-08-14-10-task · overall_score · leader | 80.00100% of row best · points · Gemini 3.1 Pro (high thinking) · 8,095 output tokens / case | 75.6095% of row best · points · Gemini 3.5 Flash (high thinking) · 13,604 output tokens / case |
| Overall ResultCounted from the protocol-matched rows above · 3 ties | 2 benchmark winsOverall lead | 1 benchmark win |
Third-party benchmark Only like-for-like primary-publisher results are shown; raw scores, relative scores, configuration, and token spend remain visible.
Technical Differences
Side-by-Side Facts
| Field | Gemini 3.1 Pro | Gemini 3.5 Flash |
|---|---|---|
| Developer | Google DeepMind | Google DeepMind |
| Family | Gemini 3 | Gemini 3 |
| Model | Gemini 3.1 Pro | Gemini 3.5 Flash |
| Version | Gemini 3.1 Pro | Gemini 3.5 Flash |
| Lifecycle | preview | active |
| Released | Unknown | Unknown |
| Knowledge cutoff | Unknown | Unknown |
| Input modalities | Text, Image, Video, Audio, Document | Text, Image, Video, Audio, Document |
| Output modalities | Text | Text |
| Context window | 1,048,576 | 1,048,576 |
| Total parameters | Unknown | Unknown |
| Active parameters | Unknown | Unknown |
| License | Unknown | Unknown |
| Open weights | No | No |
| API available | Yes | Yes |
| Self-hostable | No | No |
| Provider access | Google AI (Standard) | Google AI (Standard) |
| Capabilities | chat, generation, reasoning, tools | chat, generation, reasoning, tools |
13 comparable fields · 3 material differences · Pair passes the primary-source comparison gate
Gemini 3.1 Pro Capabilities
Gemini 3.5 Flash Capabilities
Internal Comparison Graph
Related Comparisons
| A | Pair | B | Context |
|---|---|---|---|
Claude Fable 5.1Anthropic | vs | Gemini 3.1 ProGoogle DeepMind | cross-developer peerstext |
Claude Mythos 5.1Anthropic | vs | Gemini 3.1 ProGoogle DeepMind | cross-developer peerstext |
 DeepSeek-V4-Flash-Vision-ExpDeepSeek | vs | Gemini 3.1 ProGoogle DeepMind | cross-developer peerstext |
Gemini 3.1 ProGoogle DeepMind | vs |  Hy4 previewTencent | cross-developer peerstext |
Gemini 2.5 ProGoogle DeepMind | vs | Gemini 3.1 ProGoogle DeepMind | family variantstext |
Gemini 3 FlashGoogle DeepMind | vs | Gemini 3.5 FlashGoogle DeepMind | family variantstext |
Gemini 2.5 Flash-LiteGoogle DeepMind | vs | Gemini 3.5 FlashGoogle DeepMind | family variantstext |
Gemini 2.5 FlashGoogle DeepMind | vs | Gemini 3.5 FlashGoogle DeepMind | family variantstext |
Gemini 3.5 FlashGoogle DeepMind | vs |  GLM-5.3-FlashZ.ai | cross-developer peerstext |
Gemini 3.5 FlashGoogle DeepMind | vs |  Qwen3.8-FlashQwen | cross-developer peerstext |
Gemini 3.1 ProGoogle DeepMind | vs | GLM-5V-TurboZ.ai | cross-developer peerstext |
Gemini Deep ResearchGoogle DeepMind | vs | Gemini 3.1 ProGoogle DeepMind | family variantstext |
Primary Evidence
Sources and Freshness
Questions
Gemini 3.1 Pro vs Gemini 3.5 Flash FAQs
Is Gemini 3.1 Pro or Gemini 3.5 Flash better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Gemini 3.1 Pro and Gemini 3.5 Flash, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Gemini 3.1 Pro or Gemini 3.5 Flash?+
Gemini 3.1 Pro is $2.00 and Gemini 3.5 Flash is $1.50 per million tokens, so Gemini 3.5 Flash is cheaper on this metric. Gemini 3.1 Pro is $12.00 and Gemini 3.5 Flash is $9.00 per million tokens, so Gemini 3.5 Flash is cheaper on this metric.
Which has a larger context window, Gemini 3.1 Pro or Gemini 3.5 Flash?+
Neither model has a larger sourced context window in this comparison. Gemini 3.1 Pro is 1,048,576 and Gemini 3.5 Flash is 1,048,576.
Which performs better in benchmarks, Gemini 3.1 Pro or Gemini 3.5 Flash?+
Gemini 3.1 Pro leads the current overall benchmark count. The result uses 6 protocol-matched benchmarks from 3 publishers; it is not a universal quality score.
Can Gemini 3.1 Pro or Gemini 3.5 Flash be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. Gemini 3.1 Pro is not marked open weight; Gemini 3.5 Flash is not marked open weight.
Can Gemini 3.1 Pro and Gemini 3.5 Flash understand images?+
Gemini 3.1 Pro is documented with image input; Gemini 3.5 Flash is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, Gemini 3.1 Pro or Gemini 3.5 Flash?+
Neither has a larger sourced maximum output. Gemini 3.1 Pro is 65,536 and Gemini 3.5 Flash is 65,536.
Do Gemini 3.1 Pro and Gemini 3.5 Flash support reasoning and tool use?+
Gemini 3.1 Pro: reasoning, tool calling, and image input. Gemini 3.5 Flash: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, Gemini 3.1 Pro or Gemini 3.5 Flash?+
Gemini 3.1 Pro has 1 sourced provider route; Gemini 3.5 Flash has 1, a tie.
Which offers better value, Gemini 3.1 Pro or Gemini 3.5 Flash?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.