Gemini 3.1 Flash Lite or GPT-5 Mini: which to choose?

Side-by-side comparison

Criterion	Gemini 3.1 Flash Lite	GPT-5 Mini
Developer	Google DeepMind	OpenAI
Released	May 7, 2026	August 7, 2025
Capability index	64.3 / 100	62.9 / 100
Input price	$0.25	$0.25
Output price	$1.5	$2
Cost of a typical task	$0.008	$0.009
Context window	1,048,576 tokens	272,000 tokens
Maximum output	65,536 tokens	8,192 tokens
Reasoning mode	Yes	Yes
Tool calling	Yes	Yes
Accepted inputs	text, image, video, audio, PDF	text, image
Open weights	No	No
Knowledge cutoff	January 2025	May 30, 2024

The match-up at a glance

Gemini 3.1 Flash Lite and GPT-5 Mini are two budget models, built for high volumes at a low price, one from Google DeepMind, the other from OpenAI. Gemini 3.1 Flash Lite was released on May 7, 2026, GPT-5 Mini on August 7, 2025.

All figures below come from public sources checked on October 22, 2026: models.dev and OpenRouter for prices and capabilities, Epoch AI for scores.

What the benchmarks say

On our capability index, Gemini 3.1 Flash Lite scores 64.3 out of 100 and GPT-5 Mini 62.9. Gemini 3.1 Flash Lite leads by 1.4 points.

On the 4 benchmarks reported for both, Gemini 3.1 Flash Lite wins 1 time and GPT-5 Mini 3:

GPQA Diamond (PhD-level science questions): Gemini 3.1 Flash Lite 81.8%, GPT-5 Mini 75%
OTIS Mock AIME (competition mathematics problems): Gemini 3.1 Flash Lite 80%, GPT-5 Mini 86.7%
FrontierMath (very hard research-level mathematics): Gemini 3.1 Flash Lite 27.7%, GPT-5 Mini 46.7%
Humanity's Last Exam (multidisciplinary expert questions): Gemini 3.1 Flash Lite 8.6%, GPT-5 Mini 19.4%

Pricing

Gemini 3.1 Flash Lite costs $0.25 per million input tokens and $1.5 per million output tokens; GPT-5 Mini costs $0.25 and $2.

For a typical agent task (read 20,000 tokens, write 2,000), expect $0.008 with Gemini 3.1 Flash Lite versus $0.009 with GPT-5 Mini. The cost is almost the same.

Run the numbers with your own volumes in the agent cost calculator.

Under the hood

Gemini 3.1 Flash Lite reads more in one go: 1,048,576 tokens of context (roughly 1,573 pages), versus 272,000 for GPT-5 Mini.

Reasoning mode: Gemini 3.1 Flash Lite yes, GPT-5 Mini yes. Tool calling: Gemini 3.1 Flash Lite yes, GPT-5 Mini yes. Image input: Gemini 3.1 Flash Lite yes, GPT-5 Mini yes.

Neither publishes its weights: both are used through an API.

Knowledge cutoff: January 2025 for Gemini 3.1 Flash Lite, May 30, 2024 for GPT-5 Mini.

In short

Our reading of the data:

Choose Gemini 3.1 Flash Lite for a higher capability index, a larger context window and a more recent release.

This verdict relies on public figures; it does not replace a trial on your own tasks.

Frequently asked questions

Gemini 3.1 Flash Lite or GPT-5 Mini: which is better?

On our index (Epoch AI data), Gemini 3.1 Flash Lite scores 64.3 and GPT-5 Mini 62.9 out of 100. The best choice also depends on price and on your use case.

Which one is cheaper?

Gemini 3.1 Flash Lite. To read 20,000 tokens and write 2,000, expect $0.008 with Gemini 3.1 Flash Lite and $0.009 with GPT-5 Mini (prices as of October 22, 2026).

Which one has the larger context window?

Gemini 3.1 Flash Lite, with 1,048,576 tokens versus 272,000.

Can I run Gemini 3.1 Flash Lite or GPT-5 Mini on my own servers?

No: both are closed models, available through an API.

Gemini 3.1 Flash Lite vs GPT-5 Mini