Model comparison - Same provider, successor

Gemini 3.1 Flash-Lite vs Gemini 3.5 Flash-Lite

Gemini 3.1 Flash-Lite and Gemini 3.5 Flash-Lite are both Google models. On list price, Gemini 3.1 Flash-Lite charges 17% less than Gemini 3.5 Flash-Lite for input ($0.25 vs $0.30 per 1M tokens), and Gemini 3.5 Flash-Lite charges 1.7x Gemini 3.1 Flash-Lite's output price ($2.50 vs $1.50 per 1M tokens). Gemini 3.1 Flash-Lite and Gemini 3.5 Flash-Lite both have a 1,048,576-token context window, and both return up to 65,536 output tokens per response. Gemini 3.1 Flash-Lite was released on May 7, 2026 and Gemini 3.5 Flash-Lite on July 21, 2026. Both are closed-weights models, available only through an API.

Last verified October 17, 2026 from each provider's pricing page. All sources

Google - Closed

Gemini 3.1 Flash-Lite

Input / 1M: $0.25
Output / 1M: $1.50
Context: 1.05M

Google - Closed

Gemini 3.5 Flash-Lite

Input / 1M: $0.30
Output / 1M: $2.50
Context: 1.05M

Side-by-side specs

Spec	Gemini 3.1 Flash-Lite	Gemini 3.5 Flash-Lite
Provider	Google	Google
Input / 1M tokens	$0.25	$0.30
Output / 1M tokens	$1.50	$2.50
Cache read / 1M	$0.025	$0.03
Batch input / 1M	$0.125	$0.15
Batch output / 1M	$0.75	$1.25
Context window	1,048,576	1,048,576
Max output	65,536	65,536
Release date	May 7, 2026	July 21, 2026
Weights	Closed	Closed
API model id	`gemini-3.1-flash-lite`	`gemini-3.5-flash-lite`
AI Gateway id	`google/gemini-3.1-flash-lite`	`google/gemini-3.5-flash-lite`
Last verified	October 17, 2026	October 17, 2026

Prices in USD per 1M tokens at each provider's standard first-party rate. A dash means the provider does not bill that item separately or no primary page states it.

What each costs in practice

The same three workloads every model page uses, worked from each model's standard list rates. Swap in your own token counts with the math on each model's page.

Workload	Gemini 3.1 Flash-Lite	Gemini 3.5 Flash-Lite
One agent session1M input tokens and 100K output tokens, no caching.	$0.40	$0.55
A chat app10,000 requests a day at 2K input and 500 output tokens each.	$12.50$375.00 per 30-day month	$18.50$555.00 per 30-day month
The same session at a 90% cache hit90% of the input is read from the prompt cache. The one-time cache write premium is not included.	$0.1975	$0.307

Show the math

Gemini 3.1 Flash-Lite

One agent sessionInput: 1M x $0.25 = $0.25Output: 0.1M x $1.50 = $0.15
A chat appInput: 20M x $0.25 = $5.00Output: 5M x $1.50 = $7.50
The same session at a 90% cache hitCached input: 0.9M x $0.025 = $0.0225Uncached input: 0.1M x $0.25 = $0.025Output: 0.1M x $1.50 = $0.15

Gemini 3.5 Flash-Lite

One agent sessionInput: 1M x $0.30 = $0.30Output: 0.1M x $2.50 = $0.25
A chat appInput: 20M x $0.30 = $6.00Output: 5M x $2.50 = $12.50
The same session at a 90% cache hitCached input: 0.9M x $0.03 = $0.027Uncached input: 0.1M x $0.30 = $0.03Output: 0.1M x $2.50 = $0.25

Benchmarks under the same setting

No board in the benchmark directory lists both Gemini 3.1 Flash-Lite and Gemini 3.5 Flash-Lite under the same setting, so there is no like-for-like score to show here.

Set them up in your tools

Step-by-step guides whose official docs list Gemini 3.1 Flash-Lite or Gemini 3.5 Flash-Lite by model id.

Model pages

GoogleGemini 3.1 Flash-Lite pricing and specsFull rate card, worked cost examples and sources. Closed weights.GoogleGemini 3.5 Flash-Lite pricing and specsFull rate card, worked cost examples and sources. Closed weights.

FAQ

How do Gemini 3.1 Flash-Lite and Gemini 3.5 Flash-Lite compare on price?

On list price, Gemini 3.1 Flash-Lite charges 17% less than Gemini 3.5 Flash-Lite for input ($0.25 vs $0.30 per 1M tokens), and Gemini 3.5 Flash-Lite charges 1.7x Gemini 3.1 Flash-Lite's output price ($2.50 vs $1.50 per 1M tokens). For one agent session of 1M input and 100K output tokens with no caching, that is $0.40 on Gemini 3.1 Flash-Lite and $0.55 on Gemini 3.5 Flash-Lite. Prices are each provider's first-party list rates, verified October 17, 2026 and October 17, 2026.

What are the context windows of Gemini 3.1 Flash-Lite and Gemini 3.5 Flash-Lite?

Gemini 3.1 Flash-Lite and Gemini 3.5 Flash-Lite both have a 1,048,576-token context window, and both return up to 65,536 output tokens per response.

Are Gemini 3.1 Flash-Lite and Gemini 3.5 Flash-Lite open weights?

Gemini 3.1 Flash-Lite is closed-weights and is called through Google's API as gemini-3.1-flash-lite. Gemini 3.5 Flash-Lite is closed-weights and is called through Google's API as gemini-3.5-flash-lite.

More comparisons

Sources

Gemini 3.1 Flash-Lite verified October 17, 2026 from ai.google.dev; Gemini 3.5 Flash-Lite verified October 17, 2026 from ai.google.dev. This page is as current as the older of the two: October 17, 2026.

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