GLM 5.3 Flash vs gpt-oss-120b

Updated October 21, 2026. 54 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace GLM 5.3 Flash Replace gpt-oss-120b

GLM 5.3 FlashZ.ai

Coding: 71.0
Overall: 41.8
Output $/M: $0.50

gpt-oss-120bOpenAI

Coding: 34.5
Overall: 11.6
Output $/M: $0.60

vs boards won of 54 shared

Decision reading

Pick GLM 5.3 Flash for coding: it scores 71.0 on the Vibe Coding Index against 34.5 for gpt-oss-120b.

Pick gpt-oss-120b when what matters is LiveCodeBench (Vals AI) or ALE-Bench, where it leads.

Model AGLM 5.3 FlashZ.ai71.0/1002 independent benchmarks$0.02 per solved task Model Bgpt-oss-120bOpenAI34.5/1002 independent benchmarks$0.51 per solved task

544824

Shared results: 54
GLM 5.3 Flash only: 48
gpt-oss-120b only: 24
Like-for-like categories: 8 of 9

Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.

Which one for your work

Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.

Coding
Vibe Coding Index, four public coding benchmarks
GLM 5.3 Flash
GLM 5.3 Flash scores 71.0 against 34.5.
2 benchmarks behind each score
Intelligence
AA Intelligence Index
GLM 5.3 Flash
GLM 5.3 Flash leads, 41.8 against 11.6.
Same board, both measured
Agentic work
AA Agentic Index
GLM 5.3 Flash
GLM 5.3 Flash leads, 50.9 against 3.7.
Same board, both measured
Reasoning
GPQA Diamond
GLM 5.3 Flash
GLM 5.3 Flash leads, 86.4% against 78.5%.
Same board, both measured
Math
AIME
No call
Only gpt-oss-120b has a AIME result, 92.6%.
Directional only
Knowledge
MMLU Pro
GLM 5.3 Flash
GLM 5.3 Flash leads, 86.1% against 79.2%.
Same board, both measured
Web design
Design Arena: websites
GLM 5.3 Flash
GLM 5.3 Flash leads, 1272 against 968.
Same board, both measured
General
Vals Index
No call
Only GLM 5.3 Flash has a Vals Index result, 50.9%.
Directional only
Long documents
Listed context window
GLM 5.3 Flash
GLM 5.3 Flash takes 1.05M tokens against 131K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
GLM 5.3 Flash
GLM 5.3 Flash $0.0004, gpt-oss-120b $0.0004 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
GLM 5.3 Flash
GLM 5.3 Flash $0.02, gpt-oss-120b $0.51.
Published attempt cost and pass rate

At a glance

Coding index: GLM 5.3 Flash 71.0 from 2 benchmarks, gpt-oss-120b 34.5 from 2 benchmarks.
Widest category: Agentic work, 47.8 points apart on average over 2 shared benchmarks.
Widest single gap: SWE-bench Verified (Vals AI): GLM 5.3 Flash 92.0% against gpt-oss-120b 33.6%, 58.4 points apart on a 0 to 100 scale.
Output price: GLM 5.3 Flash $0.50 against gpt-oss-120b $0.60 per million output tokens, 1.2x apart.
Context window: GLM 5.3 Flash takes 1.05M tokens, gpt-oss-120b 131K.

Benchmark by benchmark

First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.

Boards won, where both have a result
Category	GLM 5.3 Flash	gpt-oss-120b
Coding	5	2
Intelligence	2	0
Agentic work	2	0
Reasoning	8	0
Math	3	0
Knowledge	7	0
Web design	6	0
General	19	0
All shared boards	52	2

CodingLike-for-likeFour of these boards feed the Vibe Coding Index52

Coding benchmarks for GLM 5.3 Flash and gpt-oss-120b
Benchmark	GLM 5.3 Flash	gpt-oss-120b	Leader
Aider polyglot	Not measured	41.8%	Only gpt-oss-120b measured
SWE-bench Verified	Not measured	26.0%	Only gpt-oss-120b measured
LiveBench coding	80.6%	Not measured	Only GLM 5.3 Flash measured
LMArena WebDev	1607	Not measured	Only GLM 5.3 Flash measured
AA Coding Index	71.5	30.4	GLM 5.3 Flash
LiveCodeBench (Vals AI)	80.5%	83.2%	gpt-oss-120b
SWE-bench Verified (Vals AI)	92.0%	33.6%	GLM 5.3 Flash
Terminal-Bench 4 (Vals AI)	37.4%	Not measured	Only GLM 5.3 Flash measured
Vibe Code Bench (Vals AI)	30.8%	Not measured	Only GLM 5.3 Flash measured
Code migration (Vals AI)	20.5%	Not measured	Only GLM 5.3 Flash measured
ProgramBench (Vals AI)	0.0%	Not measured	Only GLM 5.3 Flash measured
IOI (Vals AI)	52.5%	Not measured	Only GLM 5.3 Flash measured
Terminal-Bench 2.1 (Vals AI)	62.9%	Not measured	Only GLM 5.3 Flash measured
Vibe Code Bench 1-100 (Vals AI)	16.0%	Not measured	Only GLM 5.3 Flash measured
SkillsBench (Vals AI)	40.2%	Not measured	Only GLM 5.3 Flash measured
CyberBench (Vals AI)	67.9%	Not measured	Only GLM 5.3 Flash measured
LiveCodeBench (Artificial Analysis run)	Not measured	87.8%	Only gpt-oss-120b measured
SciCode	51.6%	34.0%	GLM 5.3 Flash
Terminal-Bench Hard (Artificial Analysis run)	Not measured	23.5%	Only gpt-oss-120b measured
Terminal-Bench	Not measured	18.7%	Only gpt-oss-120b measured
FrontierCode	31.8%	Not measured	Only GLM 5.3 Flash measured
FrontierSWE	18.1%	Not measured	Only GLM 5.3 Flash measured
WeirdML	Not measured	48.2%	Only gpt-oss-120b measured
ALE-Bench	303.6	575.6	gpt-oss-120b
LMArena Text: coding	1507	1379	GLM 5.3 Flash
LMArena Text: software and IT	1500	1387	GLM 5.3 Flash
LMArena WebDev: React	1624	Not measured	Only GLM 5.3 Flash measured
LMArena WebDev: HTML	1577	Not measured	Only GLM 5.3 Flash measured
LMArena WebDev: from an image	1578	Not measured	Only GLM 5.3 Flash measured
Neither model has a result on the other 9 boards here

IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20

Intelligence benchmarks for GLM 5.3 Flash and gpt-oss-120b
Benchmark	GLM 5.3 Flash	gpt-oss-120b	Leader
AA Intelligence Index	41.8	11.6	GLM 5.3 Flash
Epoch Capabilities Index	153.1	139.8	GLM 5.3 Flash

Agentic workLike-for-likePublic boards, shown as published, kept out of the index20

Agentic work benchmarks for GLM 5.3 Flash and gpt-oss-120b
Benchmark	GLM 5.3 Flash	gpt-oss-120b	Leader
AA Agentic Index	50.9	3.7	GLM 5.3 Flash
LiveBench research	70.1%	Not measured	Only GLM 5.3 Flash measured
LiveBench browser	84.0%	Not measured	Only GLM 5.3 Flash measured
LiveBench long agentic	28.4%	Not measured	Only GLM 5.3 Flash measured
SREBench (Vals AI)	0.8%	Not measured	Only GLM 5.3 Flash measured
Finance Agent (Vals AI)	57.9%	Not measured	Only GLM 5.3 Flash measured
Tax Agent Bench (Vals AI)	31.6%	Not measured	Only GLM 5.3 Flash measured
Legal Research Bench (Vals AI)	45.2%	Not measured	Only GLM 5.3 Flash measured
Harvey's Legal Agent Benchmark (Vals AI)	10.4%	Not measured	Only GLM 5.3 Flash measured
Excel Modeling Benchmark (Vals AI)	55.9%	Not measured	Only GLM 5.3 Flash measured
Terminal-Bench-Science (Vals AI)	2.9%	Not measured	Only GLM 5.3 Flash measured
τ²-Bench Telecom	Not measured	65.8%	Only gpt-oss-120b measured
APEX-Agents	52.8%	4.4%	GLM 5.3 Flash
METR time horizons	Not measured	56.6%	Only gpt-oss-120b measured
Vending-Bench 2	Not measured	-$22	Only gpt-oss-120b measured
Neither model has a result on the other 24 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index80

Reasoning benchmarks for GLM 5.3 Flash and gpt-oss-120b
Benchmark	GLM 5.3 Flash	gpt-oss-120b	Leader
GPQA Diamond	86.4%	78.5%	GLM 5.3 Flash
LiveBench reasoning	77.6%	Not measured	Only GLM 5.3 Flash measured
MMMU Pro (Vals AI)	86.0%	Not measured	Only GLM 5.3 Flash measured
GPQA Diamond (Artificial Analysis run)	91.2%	78.2%	GLM 5.3 Flash
Humanity's Last Exam (Artificial Analysis run)	39.9%	19.6%	GLM 5.3 Flash
GPQA Diamond (Epoch AI run)	90.2%	75.8%	GLM 5.3 Flash
ARC-AGI	91.0%	Not measured	Only GLM 5.3 Flash measured
ARC-AGI-2	65.8%	Not measured	Only GLM 5.3 Flash measured
SimpleBench	Not measured	22.1%	Only gpt-oss-120b measured
Chess puzzles	21.0%	Not measured	Only GLM 5.3 Flash measured
Mystery game puzzles	8.0%	2.0%	GLM 5.3 Flash
LMArena Text: hard prompts	1490	1364	GLM 5.3 Flash
LMArena Text: expert	1511	1356	GLM 5.3 Flash
LMArena Text: hard prompts in English	1488	1368	GLM 5.3 Flash
LMArena Vision: diagrams	1317	Not measured	Only GLM 5.3 Flash measured
LMArena Vision: homework	1318	Not measured	Only GLM 5.3 Flash measured
Neither model has a result on the other 5 boards here

MathLike-for-likePublic boards, shown as published, kept out of the index30

Math benchmarks for GLM 5.3 Flash and gpt-oss-120b
Benchmark	GLM 5.3 Flash	gpt-oss-120b	Leader
AIME	Not measured	92.6%	Only gpt-oss-120b measured
MATH 500 (Vals AI)	Not measured	94.8%	Only gpt-oss-120b measured
MGSM (Vals AI)	Not measured	92.0%	Only gpt-oss-120b measured
AA Math Index	Not measured	93.4	Only gpt-oss-120b measured
AIME 2025 (Artificial Analysis run)	Not measured	93.4%	Only gpt-oss-120b measured
OTIS Mock AIME	93.9%	88.9%	GLM 5.3 Flash
FrontierMath, tiers 1 to 3	55.8%	Not measured	Only GLM 5.3 Flash measured
FrontierMath, tier 4	17.1%	Not measured	Only GLM 5.3 Flash measured
ProofBench	21.0%	Not measured	Only GLM 5.3 Flash measured
LMArena Text: math	1503	1389	GLM 5.3 Flash
LMArena Text: mathematical work	1497	1386	GLM 5.3 Flash
Neither model has a result on the other 2 boards here

KnowledgeLike-for-likePublic boards, shown as published, kept out of the index70

Knowledge benchmarks for GLM 5.3 Flash and gpt-oss-120b
Benchmark	GLM 5.3 Flash	gpt-oss-120b	Leader
MMLU Pro	86.1%	79.2%	GLM 5.3 Flash
LegalBench (Vals AI)	83.9%	75.9%	GLM 5.3 Flash
CaseLaw (Vals AI)	Not measured	48.8%	Only gpt-oss-120b measured
CorpFin (Vals AI)	Not measured	58.2%	Only gpt-oss-120b measured
TaxEval (Vals AI)	75.6%	71.6%	GLM 5.3 Flash
MedQA (Vals AI)	Not measured	91.4%	Only gpt-oss-120b measured
MMLU Pro (Artificial Analysis run)	Not measured	80.8%	Only gpt-oss-120b measured
LMArena Text: science	1484	1382	GLM 5.3 Flash
LMArena Text: medicine and healthcare	1475	1388	GLM 5.3 Flash
LMArena Text: legal and government	1473	1355	GLM 5.3 Flash
LMArena Text: business and finance	1460	1359	GLM 5.3 Flash
Neither model has a result on the other 6 boards here

Web designLike-for-likePublic boards, shown as published, kept out of the index60

Web design benchmarks for GLM 5.3 Flash and gpt-oss-120b
Benchmark	GLM 5.3 Flash	gpt-oss-120b	Leader
Design Arena: websites	1272	968	GLM 5.3 Flash
Design Arena: UI components	1316	927	GLM 5.3 Flash
Design Arena: game dev	1279	992	GLM 5.3 Flash
Design Arena: data viz	1262	987	GLM 5.3 Flash
Design Arena: 3D	1316	901	GLM 5.3 Flash
Design Arena: all code categories	1282	963	GLM 5.3 Flash
Design Arena: SVG	1284	Not measured	Only GLM 5.3 Flash measured
Design Arena: ASCII art	1269	Not measured	Only GLM 5.3 Flash measured
LiveBench design	77.2%	Not measured	Only GLM 5.3 Flash measured

GeneralLike-for-likePublic boards, shown as published, kept out of the index190

General benchmarks for GLM 5.3 Flash and gpt-oss-120b
Benchmark	GLM 5.3 Flash	gpt-oss-120b	Leader
Vals Index	50.9%	Not measured	Only GLM 5.3 Flash measured
LiveBench data analysis	76.4%	Not measured	Only GLM 5.3 Flash measured
MedScribe (Vals AI)	88.9%	Not measured	Only GLM 5.3 Flash measured
IFBench	Not measured	69.0%	Only gpt-oss-120b measured
Long context reasoning (AA-LCR)	80.0%	52.0%	GLM 5.3 Flash
DTBench	Not measured	76.3%	Only gpt-oss-120b measured
LMCA	Not measured	22.1%	Only gpt-oss-120b measured
Fiction.LiveBench	Not measured	44.4%	Only gpt-oss-120b measured
Creative writing (Lech Mazur)	Not measured	77.1%	Only gpt-oss-120b measured
Surface Evolver Bench	52.5%	25.0%	GLM 5.3 Flash
LMArena Text	1471	1366	GLM 5.3 Flash
LMArena Text: instruction following	1478	1318	GLM 5.3 Flash
LMArena Text: creative writing	1441	1274	GLM 5.3 Flash
LMArena Vision	1294	Not measured	Only GLM 5.3 Flash measured
LMArena Text: English	1474	1375	GLM 5.3 Flash
LMArena Text: non-English	1462	1351	GLM 5.3 Flash
LMArena Text: Chinese	1531	1385	GLM 5.3 Flash
LMArena Text: German	1462	1353	GLM 5.3 Flash
LMArena Text: Japanese	1444	1331	GLM 5.3 Flash
LMArena Text: Korean	1436	1282	GLM 5.3 Flash
LMArena Text: French	1491	1370	GLM 5.3 Flash
LMArena Text: Spanish	1475	1389	GLM 5.3 Flash
LMArena Text: Russian	1465	1343	GLM 5.3 Flash
LMArena Text: Polish	1450	1353	GLM 5.3 Flash
LMArena Text: multi-turn	1469	1340	GLM 5.3 Flash
LMArena Text: longer queries	1481	1319	GLM 5.3 Flash
LMArena Text: writing and language	1455	1306	GLM 5.3 Flash
LMArena Text: entertainment and media	1440	1292	GLM 5.3 Flash
LMArena Vision: English	1295	Not measured	Only GLM 5.3 Flash measured
LMArena Vision: Chinese	1363	Not measured	Only GLM 5.3 Flash measured
LMArena Vision: reading text	1299	Not measured	Only GLM 5.3 Flash measured
LMArena Vision: humor	1279	Not measured	Only GLM 5.3 Flash measured
LMArena Vision: creative writing	1270	Not measured	Only GLM 5.3 Flash measured
Neither model has a result on the other 13 boards here

Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared

Image generation benchmarks for GLM 5.3 Flash and gpt-oss-120b
Benchmark	GLM 5.3 Flash	gpt-oss-120b	Leader
Neither model has a result on 5 boards here

What each workload costs

Three fixed token mixes at each model's listed price, so per-token rates become a bill.

Chat turn

1K input + 500 output tokens

GLM 5.3 Flash$0.0004Fits in one request

gpt-oss-120b$0.0004Fits in one request

GLM 5.3 Flash costs less

Repository review

50K input + 3K output tokens

GLM 5.3 Flash$0.0090Fits in one request

gpt-oss-120b$0.0093Fits in one request

GLM 5.3 Flash costs less

Agent loop

200K input + 10K output tokens

GLM 5.3 Flash$0.035Fits in one request

gpt-oss-120b$0.036Exceeds the context window

GLM 5.3 Flash costs less

Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.

Specification differences

The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.

Specifications of GLM 5.3 Flash and gpt-oss-120b
Specification	Z.ai GLM 5.3 Flash	OpenAI gpt-oss-120b
Maker	Z.ai	OpenAI
Weights	Open weights	Open weights
Released	August 26, 2026	August 5, 2025
Context window	1.05M	131K
Input $/Mtok	$0.15	$0.15
Output $/Mtok	$0.50	$0.60
Coding index	71.0	34.5
Independent measurements behind it	2	2
Cost per solved task	$0.02	$0.51
Source	OpenRouter listing	OpenRouter listing

Questions

Is GLM 5.3 Flash better than gpt-oss-120b for coding?

Pick GLM 5.3 Flash for coding: it scores 71.0 on the Vibe Coding Index against 34.5 for gpt-oss-120b. Pick gpt-oss-120b when what matters is LiveCodeBench (Vals AI) or ALE-Bench, where it leads.

Which is cheaper, GLM 5.3 Flash or gpt-oss-120b?

GLM 5.3 Flash costs $0.15 per million input tokens and $0.50 per million output tokens; gpt-oss-120b costs $0.15 and $0.60. Per solved SWE-bench Verified task, GLM 5.3 Flash costs $0.02 and gpt-oss-120b $0.51.

Which has the bigger context window, GLM 5.3 Flash or gpt-oss-120b?

GLM 5.3 Flash, with 1.05M tokens against 131K.

How many benchmarks is the GLM 5.3 Flash vs gpt-oss-120b comparison based on?

54 benchmarks have a result for both models as of October 21, 2026. GLM 5.3 Flash's coding index rests on 2 independent benchmarks and gpt-oss-120b's on 2. Where only one model has a result, the page says so instead of naming a winner.

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<iframe src="https://llmbenchmark.ai/embed/compare/glm-5-3-flash-vs-gpt-oss-120b" title="GLM 5.3 Flash vs gpt-oss-120b, LLMBenchmark.ai" width="100%" height="360" style="border:0;max-width:100%" loading="lazy"></iframe>
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Decision reading

Which one for your work

Coding

Intelligence

Agentic work

Reasoning

Math

Knowledge

Web design

General

Long documents

Everyday cost

Cost per solved task

At a glance

Benchmark by benchmark

What each workload costs

Chat turn

Repository review

Agent loop

Specification differences

Questions

Compare next