Model comparison

Gemini 3.1 Flash Lite vs GPT-5.3 Chat

GPT-5.3 Chat is the stronger model overall, scoring 42.1 to 40.4 on the Noometry Index. Gemini 3.1 Flash Lite costs 8.6× less per token, which makes it the better buy when GPT-5.3 Chat's lead doesn't matter for your workload.

Last verified October 10, 2026. 17 shared benchmarks.

Gemini 3.1 Flash Lite

Google

40.4

Rank #141 Confirmed

GPT-5.3 Chat OpenAI

42.1

Rank #109 Confirmed

Summary

They share 17 benchmarks with published results for both. Gemini 3.1 Flash Lite scores higher in 3 categories and GPT-5.3 Chat in 5 categories; 6 gaps are clear of the uncertainty.
The widest gap is in reasoning, where GPT-5.3 Chat leads 27.3 to 22.3.
Gemini 3.1 Flash Lite is cheaper at $0.25 / $1.50 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Chat.
Gemini 3.1 Flash Lite accepts more context: 1.05M tokens versus 128K.

Side by side

Gemini 3.1 Flash Lite and GPT-5.3 Chat specifications
	Gemini 3.1 Flash Lite	GPT-5.3 Chat
Provider	Google	OpenAI
Noometry Index	40.4	42.1
Released	2026-03-03	2026-03-03
Weights	Proprietary	Proprietary
Context window	1.05M	128K
Max output	66K	16K
Input $ / M tokens	$0.25	$1.75
Output $ / M tokens	$1.50	$14
Results tracked	38	18

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Category by category

Coding GPT-5.3 Chat leads

Gemini 3.1 Flash Lite: 37.5 (#179), GPT-5.3 Chat: 40.8 (#124)

Coding benchmarks
Benchmark	Gemini 3.1 Flash Lite	GPT-5.3 Chat
LMArena Coding	1400	1408
LMArena WebDev	1256	—
SciCode	41.9%	—
WeirdML	52.2%	—
ALE-Bench	797.73	—

Agentic & Tool Use Not comparable

Gemini 3.1 Flash Lite: 29.9 (#72), GPT-5.3 Chat: —

Agentic & Tool Use benchmarks
Benchmark	Gemini 3.1 Flash Lite	GPT-5.3 Chat
DeepResearch Bench	37.3%	—

Reasoning GPT-5.3 Chat leads

Gemini 3.1 Flash Lite: 22.3 (#181), GPT-5.3 Chat: 27.3 (#105)

Reasoning benchmarks
Benchmark	Gemini 3.1 Flash Lite	GPT-5.3 Chat
LMArena Hard Prompts	1407	1399
Kagi LLM Benchmark	67.2%	—
NYT Connections (extended)	8.2%	—
CritPt	1.1%	—
Chess Puzzles	25%	—
EnigmaEval	3%	—
Thematic Generalization	63.3%	—
DTBench	76.8%	—
LMCA	35%	—
Epoch Capabilities Index	144.45	—
ForecastBench	54.4	—

Math Gemini 3.1 Flash Lite leads

Gemini 3.1 Flash Lite: 39.5 (#82), GPT-5.3 Chat: 35.4 (#146)

Math benchmarks
Benchmark	Gemini 3.1 Flash Lite	GPT-5.3 Chat
LMArena Math	1427	1389
FrontierMath (Tiers 1-3)	27.7%	—
OTIS Mock AIME 2024-2025	80%	—

Knowledge Gemini 3.1 Flash Lite leads

Gemini 3.1 Flash Lite: 41.7 (#95), GPT-5.3 Chat: 38.2 (#137)

Knowledge benchmarks
Benchmark	Gemini 3.1 Flash Lite	GPT-5.3 Chat
LMArena Expert	1397	1397
GPQA Diamond	81.8%	—
Humanity's Last Exam	8.6%	—
Vectara Hallucination Rate	8.2%	—

Multimodal Not comparable

Gemini 3.1 Flash Lite: 38.7 (#57), GPT-5.3 Chat: —

Multimodal benchmarks
Benchmark	Gemini 3.1 Flash Lite	GPT-5.3 Chat
LMArena Vision	1240	—

Multilingual Gemini 3.1 Flash Lite leads

Gemini 3.1 Flash Lite: 52.5 (#82), GPT-5.3 Chat: 50.5 (#119)

Multilingual benchmarks
Benchmark	Gemini 3.1 Flash Lite	GPT-5.3 Chat
LMArena Non-English	1410	1383
LMArena Chinese	1461	1433
LMArena French	1423	1398
LMArena German	1429	1384
LMArena Japanese	1411	1351
LMArena Korean	1393	1347
LMArena Russian	1420	1400
LMArena Spanish	1420	1371

Instruction Following Too close to call

Gemini 3.1 Flash Lite: 72.9 (#126), GPT-5.3 Chat: 73.0 (#124)

Instruction Following benchmarks
Benchmark	Gemini 3.1 Flash Lite	GPT-5.3 Chat
LMArena Instruction Following	1376	1378

Long Context Too close to call

Gemini 3.1 Flash Lite: 42.5 (#117), GPT-5.3 Chat: 42.6 (#115)

Long Context benchmarks
Benchmark	Gemini 3.1 Flash Lite	GPT-5.3 Chat
LMArena Longer Query	1394	1396

Writing & Preference GPT-5.3 Chat leads

Gemini 3.1 Flash Lite: 61.0 (#90), GPT-5.3 Chat: 63.3 (#65)

Writing & Preference benchmarks
Benchmark	Gemini 3.1 Flash Lite	GPT-5.3 Chat
LMArena Text	1416	1389
LMArena Creative Writing	1401	1356
LMArena Multi-Turn	1417	1413
EQ-Bench Creative Writing	—	1690

Frequently asked questions

Is Gemini 3.1 Flash Lite better than GPT-5.3 Chat?

Which is cheaper, Gemini 3.1 Flash Lite or GPT-5.3 Chat?

Gemini 3.1 Flash Lite is cheaper. It lists at $0.25 per million input tokens and $1.50 per million output tokens; GPT-5.3 Chat lists at $1.75 and $14.

Is Gemini 3.1 Flash Lite or GPT-5.3 Chat better for coding?

GPT-5.3 Chat scores higher on coding benchmarks: 40.8 versus 37.5 in the Noometry coding category.

Which has the bigger context window?

Gemini 3.1 Flash Lite does, with 1.05M tokens against 128K.

How many benchmarks do Gemini 3.1 Flash Lite and GPT-5.3 Chat share?

17 benchmarks have published results for both models. Gemini 3.1 Flash Lite has 38 scored results on Noometry and GPT-5.3 Chat has 18.