Gemini 3.5 Flash wins on coding (90 vs 68) and writing quality. Gemini 3.1 Flash wins on price ($0.5 vs $1.5/1M input). For most workflows, Gemini 3.5 Flash is the stronger default — excellent fast agentic model, superseded by gemini 3.6 flash.
The safest Gemini 3.5 Flash vs Gemini 3.1 Flash default, the cheaper option worth trying first, and the specialist pick — before you read the detail below.
Gemini 3.5 Flash is the strongest answer here for Gemini 3.5 Flash vs Gemini 3.1 Flash — pick it when quality of output matters more than the $1.50/1M/1M input you pay for it.
Gemini 3.1 Flash handles the same job for about 67% less per token. Start here and only move up if the output is not good enough.
Gemini 3.1 Flash is the fastest of these for Gemini 3.5 Flash vs Gemini 3.1 Flash — worth it when latency is what the reader notices, not the last few points of reasoning depth.
Gemini 3.5 Flash leads on coding with a score of 90 vs 68 for Gemini 3.1 Flash.
Gemini 3.5 Flash has the larger context window: 1.048576M vs 1M for Gemini 3.1 Flash.
Gemini 3.1 Flash is cheaper at $0.5/1M input tokens vs $1.5/1M for Gemini 3.5 Flash.
Gemini 3.5 Flash is the safer default: it is built for fast agentic coding and autonomous task execution, which covers most of what people bring to this comparison.
Choose Gemini 3.1 Flash when your work is mostly high-volume everyday AI usage where speed and cost both matter — that is the workload it was tuned for.
Gemini 3.1 Flash is the more cost-efficient option at $0.5/1M input — Gemini 3.5 Flash costs 3x more per input token, so the gap is worth taking seriously wherever token volume rather than peak quality drives the bill.
Switch the scoring lens to see whether the Gemini 3.5 Flash vs Gemini 3.1 Flash answer changes when cost, speed, or long-document depth leads the decision.
Google / Balanced / Sep 3, 2026
Excellent fast agentic model, superseded by Gemini 3.6 Flash.
Ranks models by the broadest mix of coding, writing, research, and long-context usefulness.
Starting fresh — Gemini 3.6 Flash is better and cheaper.
Where the Gemini 3.5 Flash vs Gemini 3.1 Flash recommendation shifts once you weigh price or latency differently.
Excellent fast agentic model, superseded by Gemini 3.6 Flash.
Best cheap AI for broad day-to-day work — now with 1M context.
List prices and published scores — the numbers this page's pick is built from.
| Model | Input | Output | Est. month | Context | Speed | Coding | Writing | Research |
|---|---|---|---|---|---|---|---|---|
| Gemini 3.5 FlashGoogle | $1.50/1M | $9.00/1M | $33 | 1.0M tokens | Fast | 90 | 84 | 90 |
| Gemini 3.1 FlashGoogle | $0.50/1M | $3.00/1M | $11 | 1M tokens | Very fast | 68 | 75 | 76 |
Scores out of 100 — how we evaluate models. “Est. month” is 10M in / 2M out at list price: a ceiling, no discounts.
Why each one is on the shortlist for Gemini 3.5 Flash vs Gemini 3.1 Flash, what it is genuinely good at, and where we would steer you away from it.
Ranked first here for Gemini 3.5 Flash vs Gemini 3.1 Flash: 90/100 on coding, with the widest margin of anything in this line-up.
Google's I/O 2026 headliner — a Flash-tier model that beats Gemini 3.1 Pro on agentic and coding benchmarks while running roughly 4x faster than comparable frontier models.
Starting fresh — Gemini 3.6 Flash is better and cheaper.
Was the speed-to-intelligence king from May to July 2026 — then Gemini 3.6 Flash beat it on every benchmark at lower output cost. Still excellent, but pick 3.6 Flash for new work.
Full pricing, benchmark table and release notes on the Gemini 3.5 Flash page.
The value option for Gemini 3.5 Flash vs Gemini 3.1 Flash: about 67% less per token than Gemini 3.5 Flash, at 68/100 on coding. Worth starting here and moving up only if the output disappoints.
Fast, low-cost model with a 1M token context window — the best budget default for teams running high prompt volumes.
You need premium reasoning depth or the highest coding benchmark scores.
The best all-around budget model for most teams. Faster than its predecessor, cheaper, and with a 1M context window that outclasses every other budget option.
Full pricing, benchmark table and release notes on the Gemini 3.1 Flash page.
UseRightAI recommendations are based on practical decision factors people actually feel in day-to-day use.
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Gemini 3.5 Flash wins on more of the categories we score — coding, research, reasoning — so it is the better default of the two. Gemini 3.1 Flash is the better pick when your work is mostly high-volume everyday AI usage where speed and cost both matter. Neither is universally "better": Gemini 3.5 Flash is aimed at fast agentic coding and autonomous task execution, Gemini 3.1 Flash at high-volume everyday AI usage where speed and cost both matter.
Gemini 3.1 Flash is cheaper at $0.5/1M input and $3/1M output. Gemini 3.5 Flash costs $1.5/1M input and $9/1M output.
Gemini 3.5 Flash has the larger context window at 1.048576M tokens vs Gemini 3.1 Flash's 1M. For large document analysis, Gemini 3.5 Flash is the stronger pick.
Gemini 3.5 Flash is better for coding with a score of 90 vs Gemini 3.1 Flash's 68 (out of 100). GPT-6 Astra is the overall coding leader in this directory at 100/100.
Gemini 3.1 Flash is faster with a very fast speed rating (score: 5) vs Gemini 3.5 Flash's fast rating (score: 4). Speed matters most for interactive and high-throughput work; for batch jobs the Gemini 3.5 Flash latency penalty is usually invisible.
Superseded two months later by Gemini 3.6 Flash — better scores and cheaper output. No Pro-tier sibling shipped: Gemini 3.5 Pro remains delayed, leaving 3.1 Pro as the Pro flagship. Avoid it if starting fresh — Gemini 3.6 Flash is better and cheaper. That is the main case for looking at Gemini 3.1 Flash instead.
Not as sharp as premium models on hard reasoning or complex coding. May need more validation on nuanced technical tasks. Avoid it if you need premium reasoning depth or the highest coding benchmark scores. Against Gemini 3.5 Flash specifically, the gap shows up most on coding (90 vs 68).
Take a moderate workload of 10M input and 2M output tokens a month. Gemini 3.5 Flash runs $33.00 (at $1.5/1M in and $9/1M out); Gemini 3.1 Flash runs $11.00 (at $0.5/1M in and $3/1M out). That is a $22.00/month difference — Gemini 3.1 Flash is the cheaper of the two at this volume, and the gap scales linearly as you send more. Output tokens dominate the bill on both, so prompt length matters far less than response length.
Yes, and for most teams that beats picking one. A common split is Gemini 3.5 Flash for fast agentic coding and autonomous task execution, with Gemini 3.1 Flash handling high-volume everyday AI usage where speed and cost both matter. Routing high-volume, low-stakes calls to Gemini 3.1 Flash at $0.5/1M and reserving Gemini 3.5 Flash for the hard cases is usually the cheapest arrangement that does not cost you quality.