Model comparison

Gemini 2.5 Flash-Lite vs gpt-oss-20b

Gemini 2.5 Flash-Lite is the stronger model overall, scoring 36.4 to 32.1 on the Noometry Index. gpt-oss-20b costs 4.9× less per token, which makes it the better buy when Gemini 2.5 Flash-Lite's lead doesn't matter for your workload.

Last verified October 10, 2026. 27 shared benchmarks.

Gemini 2.5 Flash-Lite

Google

36.4

Rank #208 Confirmed

gpt-oss-20b OpenAI

32.1

Rank #249 Confirmed

Summary

They share 27 benchmarks with published results for both. Gemini 2.5 Flash-Lite scores higher in 6 categories and gpt-oss-20b in 3 categories; 8 gaps are clear of the uncertainty.
The widest gap is in writing & preference, where Gemini 2.5 Flash-Lite leads 57.0 to 35.8.
The biggest single-benchmark swing is GPQA (HELM): 30.9% for Gemini 2.5 Flash-Lite and 59.4% for gpt-oss-20b.
gpt-oss-20b is cheaper at $0.018 / $0.09 per million input/output tokens, against $0.10 / $0.40 for Gemini 2.5 Flash-Lite.
Gemini 2.5 Flash-Lite accepts more context: 1.05M tokens versus 131K.
gpt-oss-20b has downloadable open weights; the other is API-only.

Side by side

Gemini 2.5 Flash-Lite and gpt-oss-20b specifications
	Gemini 2.5 Flash-Lite	gpt-oss-20b
Provider	Google	OpenAI
Noometry Index	36.4	32.1
Released	2025-06-17	2025-08-05
Weights	Proprietary	Open
Context window	1.05M	131K
Max output	66K	16K
Input $ / M tokens	$0.10	$0.018
Output $ / M tokens	$0.40	$0.09
Results tracked	33	34

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Category by category

Coding Too close to call

Gemini 2.5 Flash-Lite: 38.0 (#167), gpt-oss-20b: 37.1 (#185)

Coding benchmarks
Benchmark	Gemini 2.5 Flash-Lite	gpt-oss-20b
WeirdML	35.2%	40.9%
LMArena Coding	1373	1307
ALE-Bench	325.9	566.05
SciCode	—	34.4%

Agentic & Tool Use Gemini 2.5 Flash-Lite leads

Gemini 2.5 Flash-Lite: 27.8 (#89), gpt-oss-20b: 9.2 (#146)

Agentic & Tool Use benchmarks
Benchmark	Gemini 2.5 Flash-Lite	gpt-oss-20b
Terminal-Bench	—	3.4%
Berkeley Function Calling Leaderboard	36.9%	—

Reasoning Gemini 2.5 Flash-Lite leads

Gemini 2.5 Flash-Lite: 21.5 (#196), gpt-oss-20b: 18.8 (#251)

Reasoning benchmarks
Benchmark	Gemini 2.5 Flash-Lite	gpt-oss-20b
Kagi LLM Benchmark	40.5%	53.2%
LMArena Hard Prompts	1377	1274
DTBench	62.8%	68%
LMCA	18.1%	14.5%
Epoch Capabilities Index	133.93	137.81
CritPt	—	1.4%
Chess Puzzles	—	4%

Math gpt-oss-20b leads

Gemini 2.5 Flash-Lite: 35.5 (#144), gpt-oss-20b: 37.6 (#93)

Math benchmarks
Benchmark	Gemini 2.5 Flash-Lite	gpt-oss-20b
Omni-MATH	48%	56.5%
LMArena Math	1373	1317
OTIS Mock AIME 2024-2025	—	65.3%

Knowledge gpt-oss-20b leads

Gemini 2.5 Flash-Lite: 32.1 (#206), gpt-oss-20b: 34.6 (#186)

Knowledge benchmarks
Benchmark	Gemini 2.5 Flash-Lite	gpt-oss-20b
MMLU-Pro	53.7%	74%
GPQA (HELM)	30.9%	59.4%
LMArena Expert	1373	1258
GPQA Diamond	—	60.8%
Vectara Hallucination Rate	3.3%	—

Multimodal Not comparable

Gemini 2.5 Flash-Lite: 28.6 (#109), gpt-oss-20b: —

Multimodal benchmarks
Benchmark	Gemini 2.5 Flash-Lite	gpt-oss-20b
LMArena Vision	1198	—
VPCT	30%	—

Multilingual Gemini 2.5 Flash-Lite leads

Gemini 2.5 Flash-Lite: 49.5 (#129), gpt-oss-20b: 42.4 (#192)

Multilingual benchmarks
Benchmark	Gemini 2.5 Flash-Lite	gpt-oss-20b
LMArena Non-English	1369	1269
LMArena Chinese	1404	1311
LMArena German	1390	1249
LMArena Japanese	1359	1245
LMArena Korean	1358	1239
LMArena Russian	1373	1279
LMArena Spanish	1396	1267
LMArena French	1388	—

Instruction Following Gemini 2.5 Flash-Lite leads

Gemini 2.5 Flash-Lite: 70.2 (#163), gpt-oss-20b: 62.0 (#235)

Instruction Following benchmarks
Benchmark	Gemini 2.5 Flash-Lite	gpt-oss-20b
IFEval	81%	73.2%
LMArena Instruction Following	1366	1236

Long Context gpt-oss-20b leads

Gemini 2.5 Flash-Lite: 33.3 (#257), gpt-oss-20b: 37.9 (#203)

Long Context benchmarks
Benchmark	Gemini 2.5 Flash-Lite	gpt-oss-20b
LMArena Longer Query	1373	1251
Fiction.LiveBench	47.2%	—

Writing & Preference Gemini 2.5 Flash-Lite leads

Gemini 2.5 Flash-Lite: 57.0 (#130), gpt-oss-20b: 35.8 (#260)

Writing & Preference benchmarks
Benchmark	Gemini 2.5 Flash-Lite	gpt-oss-20b
LMArena Text	1379	1288
LMArena Creative Writing	1366	1201
WildBench	81.8%	73.7%
LMArena Multi-Turn	1367	1268
EQ-Bench Creative Writing	—	666

Frequently asked questions

Is Gemini 2.5 Flash-Lite better than gpt-oss-20b?

Which is cheaper, Gemini 2.5 Flash-Lite or gpt-oss-20b?

gpt-oss-20b is cheaper. It lists at $0.018 per million input tokens and $0.09 per million output tokens; Gemini 2.5 Flash-Lite lists at $0.10 and $0.40.

Is Gemini 2.5 Flash-Lite or gpt-oss-20b better for coding?

They score almost the same on coding (38.0 vs 37.1); test both on your own repository before choosing.

Which has the bigger context window?

Gemini 2.5 Flash-Lite does, with 1.05M tokens against 131K.

How many benchmarks do Gemini 2.5 Flash-Lite and gpt-oss-20b share?

27 benchmarks have published results for both models. Gemini 2.5 Flash-Lite has 33 scored results on Noometry and gpt-oss-20b has 34.