GLM 5.1 vs GPT-5.6 Luna

GPT-5.6 Luna leads GLM 5.1 on coding, 58.0 to 49.2 on the Vibe Coding Index, and GPT-5.6 Luna costs 3.7x less per output token ($1.20 vs $4.40 per million). Updated October 22, 2026; 73 benchmarks have a result for both.

Replace GLM 5.1 Replace GPT-5.6 Luna

GLM 5.1Z.ai

Coding: 49.2
Overall: 57.5
Output $/M: $4.40

GPT-5.6 LunaOpenAI

Coding: 58.0
Overall: 61.6
Output $/M: $1.20

vs boards won of 73 shared, 1 tied

GLM 5.1 or GPT-5.6 Luna: which to pick

Pick GPT-5.6 Luna for coding: it scores 58.0 on the Vibe Coding Index against 49.2 for GLM 5.1.

Pick GLM 5.1 for work measured by LMArena Text: coding or LMArena Text: software and IT, where it leads.

Model AGLM 5.1Z.ai49.2/1003 independent benchmarks$0.60 per solved task Model BGPT-5.6 LunaOpenAI58.0/1006 independent benchmarks$0.04 per solved task

731646

Shared results: 73
GLM 5.1 only: 16
GPT-5.6 Luna only: 46
Like-for-like categories: 8 of 9

Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.

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, six public coding benchmarks
GPT-5.6 Luna
GPT-5.6 Luna scores 58.0 against 49.2.
3 and 6 benchmarks behind the scores
Intelligence
AA Intelligence Index
GPT-5.6 Luna
GPT-5.6 Luna leads, 37.3 against 26.1.
Same board, both measured
Agentic work
AA Agentic Index
GPT-5.6 Luna
GPT-5.6 Luna leads, 42.1 against 23.9.
Same board, both measured
Reasoning
GPQA Diamond
GPT-5.6 Luna
GPT-5.6 Luna leads, 91.7% against 84.5%.
Same board, both measured
Math
AIME
No call
Only GLM 5.1 has a AIME result, 91.9%.
Directional only
Knowledge
MMLU Pro
GLM 5.1
GLM 5.1 leads, 86.9% against 86.0%.
Same board, both measured
Web design
Design Arena: websites
GLM 5.1
GLM 5.1 leads, 1290 against 1255.
Same board, both measured
Long documents
Listed context window
GPT-5.6 Luna
GPT-5.6 Luna takes 1.05M tokens against 205K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
GPT-5.6 Luna
GLM 5.1 $0.0036, GPT-5.6 Luna $0.0008 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
GPT-5.6 Luna
GLM 5.1 $0.60, GPT-5.6 Luna $0.04.
Published attempt cost and pass rate

At a glance

Coding index: GLM 5.1 49.2 from 3 benchmarks, GPT-5.6 Luna 58.0 from 6 benchmarks.
Widest category: Math, 18.1 points apart on average over 5 shared benchmarks.
Widest single gap: Vibe Code Bench (Vals AI): GLM 5.1 31.5% against GPT-5.6 Luna 77.1%, 45.6 points apart on a 0 to 100 scale.
Output price: GLM 5.1 $4.40 against GPT-5.6 Luna $1.20 per million output tokens, 3.7x apart.
Context window: GLM 5.1 takes 205K tokens, GPT-5.6 Luna 1.05M.

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 5.1	GPT-5.6 Luna	Ties
Coding	2	11	1 tie
Intelligence	0	2
Agentic work	1	4
Reasoning	4	5
Math	2	3
Knowledge	7	3
Web design	7	1
General	18	2
All shared boards	41	31	1 tie

CodingLike-for-likeSix of these boards feed the Vibe Coding Index211

Coding benchmarks for GLM 5.1 and GPT-5.6 Luna
Benchmark	GLM 5.1	GPT-5.6 Luna	Leader
LiveBench coding	Not measured	73.6%	Only GPT-5.6 Luna measured
LMArena WebDev	1508	1518	GPT-5.6 Luna
AA Coding Index	55.8	71.4	GPT-5.6 Luna
LiveCodeBench (Vals AI)	81.4%	Not measured	Only GLM 5.1 measured
SWE-bench Verified (Vals AI)	76.4%	93.0%	GPT-5.6 Luna
Terminal-Bench 4 (Vals AI)	Not measured	11.6%	Only GPT-5.6 Luna measured
Vibe Code Bench (Vals AI)	31.5%	77.1%	GPT-5.6 Luna
Code migration (Vals AI)	25.8%	44.5%	GPT-5.6 Luna
ProgramBench (Vals AI)	0.0%	0.0%	Tie
IOI (Vals AI)	Not measured	61.8%	Only GPT-5.6 Luna measured
Terminal-Bench 2.1 (Vals AI)	56.9%	79.0%	GPT-5.6 Luna
Vibe Code Bench 1-100 (Vals AI)	Not measured	22.6%	Only GPT-5.6 Luna measured
SkillsBench (Vals AI)	Not measured	60.5%	Only GPT-5.6 Luna measured
CyberBench (Vals AI)	Not measured	73.6%	Only GPT-5.6 Luna measured
SciCode	44.8%	53.6%	GPT-5.6 Luna
Terminal-Bench Hard (Artificial Analysis run)	43.2%	Not measured	Only GLM 5.1 measured
FrontierCode	Not measured	39.8%	Only GPT-5.6 Luna measured
WeirdML	57.1%	60.9%	GPT-5.6 Luna
ALE-Bench	887.1	1667.4	GPT-5.6 Luna
LMArena Text: coding	1485	1466	GLM 5.1
LMArena Text: software and IT	1484	1463	GLM 5.1
LMArena WebDev: React	1505	1508	GPT-5.6 Luna
LMArena WebDev: HTML	1508	1520	GPT-5.6 Luna
LMArena WebDev: from an image	Not measured	1517	Only GPT-5.6 Luna measured
SciCode	Not measured	6.2%	Only GPT-5.6 Luna measured
Neither model has a result on the other 14 boards here

IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02

Intelligence benchmarks for GLM 5.1 and GPT-5.6 Luna
Benchmark	GLM 5.1	GPT-5.6 Luna	Leader
AA Intelligence Index	26.1	37.3	GPT-5.6 Luna
Epoch Capabilities Index	149.8	156.5	GPT-5.6 Luna

Agentic workLike-for-likePublic boards, shown as published, kept out of the index14

Agentic work benchmarks for GLM 5.1 and GPT-5.6 Luna
Benchmark	GLM 5.1	GPT-5.6 Luna	Leader
AA Agentic Index	23.9	42.1	GPT-5.6 Luna
Design Arena: agents building web apps	1175	Not measured	Only GLM 5.1 measured
Design Arena: agents building full-stack apps	1167	Not measured	Only GLM 5.1 measured
Design Arena: agents building mobile apps	1162	Not measured	Only GLM 5.1 measured
Design Arena: agents building Android apps	1182	Not measured	Only GLM 5.1 measured
Design Arena: agents building Godot games	1053	Not measured	Only GLM 5.1 measured
Design Arena: agents building games	1164	Not measured	Only GLM 5.1 measured
Design Arena: HTML slides	1120	Not measured	Only GLM 5.1 measured
Design Arena: PowerPoint slides	1163	Not measured	Only GLM 5.1 measured
Design Arena: spreadsheets	1315	Not measured	Only GLM 5.1 measured
LiveBench research	Not measured	51.0%	Only GPT-5.6 Luna measured
LiveBench browser	Not measured	68.0%	Only GPT-5.6 Luna measured
LiveBench long agentic	Not measured	30.4%	Only GPT-5.6 Luna measured
SREBench (Vals AI)	Not measured	1.5%	Only GPT-5.6 Luna measured
Finance Agent (Vals AI)	44.8%	55.0%	GPT-5.6 Luna
Tax Agent Bench (Vals AI)	Not measured	24.8%	Only GPT-5.6 Luna measured
Legal Research Bench (Vals AI)	27.9%	36.5%	GPT-5.6 Luna
Excel Modeling Benchmark (Vals AI)	Not measured	67.1%	Only GPT-5.6 Luna measured
BioMysteryBench (Vals AI)	Not measured	61.5%	Only GPT-5.6 Luna measured
Terminal-Bench-Science (Vals AI)	Not measured	0.0%	Only GPT-5.6 Luna measured
Vals Science Index	Not measured	25.3%	Only GPT-5.6 Luna measured
τ²-Bench Telecom	97.7%	Not measured	Only GLM 5.1 measured
APEX-Agents	40.9%	43.0%	GPT-5.6 Luna
BALROG	Not measured	45.6%	Only GPT-5.6 Luna measured
Vending-Bench 2	$5,634	$4,095	GLM 5.1
Neither model has a result on the other 16 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index45

Reasoning benchmarks for GLM 5.1 and GPT-5.6 Luna
Benchmark	GLM 5.1	GPT-5.6 Luna	Leader
GPQA Diamond	84.5%	91.7%	GPT-5.6 Luna
LiveBench reasoning	Not measured	85.6%	Only GPT-5.6 Luna measured
MysteryMechanism (Vals AI)	Not measured	14.4%	Only GPT-5.6 Luna measured
MMMU Pro (Vals AI)	Not measured	85.0%	Only GPT-5.6 Luna measured
GPQA Diamond (Artificial Analysis run)	86.8%	91.1%	GPT-5.6 Luna
Humanity's Last Exam (Artificial Analysis run)	30.1%	39.5%	GPT-5.6 Luna
GPQA Diamond (Epoch AI run)	89.9%	91.6%	GPT-5.6 Luna
ARC-AGI	Not measured	88.0%	Only GPT-5.6 Luna measured
ARC-AGI-2	Not measured	59.5%	Only GPT-5.6 Luna measured
SimpleBench	55.1%	46.8%	GLM 5.1
Chess puzzles	20.0%	43.0%	GPT-5.6 Luna
Mystery game puzzles	Not measured	21.0%	Only GPT-5.6 Luna measured
LMArena Text: hard prompts	1473	1451	GLM 5.1
LMArena Text: expert	1478	1478	GLM 5.1
LMArena Text: hard prompts in English	1482	1460	GLM 5.1
LMArena Vision: diagrams	Not measured	1273	Only GPT-5.6 Luna measured
LMArena Vision: homework	Not measured	1282	Only GPT-5.6 Luna measured
Kagi LLM Benchmark	Not measured	49.1%	Only GPT-5.6 Luna measured
Neither model has a result on the other 4 boards here

MathLike-for-likePublic boards, shown as published, kept out of the index23

Math benchmarks for GLM 5.1 and GPT-5.6 Luna
Benchmark	GLM 5.1	GPT-5.6 Luna	Leader
AIME	91.9%	Not measured	Only GLM 5.1 measured
OTIS Mock AIME	93.3%	98.3%	GPT-5.6 Luna
FrontierMath, tiers 1 to 3	36.8%	82.1%	GPT-5.6 Luna
FrontierMath, tier 4	Not measured	61.0%	Only GPT-5.6 Luna measured
ProofBench	22.2%	60.0%	GPT-5.6 Luna
LMArena Text: math	1473	1459	GLM 5.1
LMArena Text: mathematical work	1470	1470	GLM 5.1
Neither model has a result on the other 6 boards here

KnowledgeLike-for-likePublic boards, shown as published, kept out of the index73

Knowledge benchmarks for GLM 5.1 and GPT-5.6 Luna
Benchmark	GLM 5.1	GPT-5.6 Luna	Leader
MMLU Pro	86.9%	86.0%	GLM 5.1
LegalBench (Vals AI)	84.4%	84.0%	GLM 5.1
CaseLaw (Vals AI)	51.5%	Not measured	Only GLM 5.1 measured
CorpFin (Vals AI)	64.5%	64.2%	GLM 5.1
TaxEval (Vals AI)	71.2%	76.2%	GPT-5.6 Luna
MortgageTax (Vals AI)	Not measured	67.3%	Only GPT-5.6 Luna measured
MedCode (Vals AI)	41.6%	42.4%	GPT-5.6 Luna
SimpleQA Verified	34.0%	41.0%	GPT-5.6 Luna
LMArena Text: science	1478	1433	GLM 5.1
LMArena Text: medicine and healthcare	1474	1399	GLM 5.1
LMArena Text: legal and government	1465	1446	GLM 5.1
LMArena Text: business and finance	1452	1439	GLM 5.1
FACTS Benchmark Suite	Not measured	35.0%	Only GPT-5.6 Luna measured
Neither model has a result on the other 5 boards here

Web designLike-for-likePublic boards, shown as published, kept out of the index71

Web design benchmarks for GLM 5.1 and GPT-5.6 Luna
Benchmark	GLM 5.1	GPT-5.6 Luna	Leader
Design Arena: websites	1290	1255	GLM 5.1
Design Arena: UI components	1292	1248	GLM 5.1
Design Arena: game dev	1265	1194	GLM 5.1
Design Arena: data viz	1366	1211	GLM 5.1
Design Arena: 3D	1336	1121	GLM 5.1
Design Arena: all code categories	1268	1231	GLM 5.1
Design Arena: SVG	1218	1194	GLM 5.1
Design Arena: ASCII art	1141	1142	GPT-5.6 Luna
LiveBench design	Not measured	76.0%	Only GPT-5.6 Luna measured

GeneralLike-for-likePublic boards, shown as published, kept out of the index182

General benchmarks for GLM 5.1 and GPT-5.6 Luna
Benchmark	GLM 5.1	GPT-5.6 Luna	Leader
LiveBench data analysis	Not measured	78.0%	Only GPT-5.6 Luna measured
Public Benefits Bench (Vals AI)	61.8%	61.2%	GLM 5.1
SAGE (Vals AI)	Not measured	44.2%	Only GPT-5.6 Luna measured
MedScribe (Vals AI)	72.3%	84.4%	GPT-5.6 Luna
Vals Multimodal Index	Not measured	69.1%	Only GPT-5.6 Luna measured
IFBench	76.3%	Not measured	Only GLM 5.1 measured
Long context reasoning (AA-LCR)	73.7%	83.7%	GPT-5.6 Luna
DTBench	Not measured	89.1%	Only GPT-5.6 Luna measured
LMCA	Not measured	48.5%	Only GPT-5.6 Luna measured
Surface Evolver Bench	Not measured	61.9%	Only GPT-5.6 Luna measured
Furniture assembly	Not measured	42.5%	Only GPT-5.6 Luna measured
ExploitBench	18.1%	Not measured	Only GLM 5.1 measured
LMArena Text	1463	1431	GLM 5.1
LMArena Text: instruction following	1453	1437	GLM 5.1
LMArena Text: creative writing	1453	1396	GLM 5.1
LMArena Vision	Not measured	1257	Only GPT-5.6 Luna measured
LMArena Text: English	1476	1441	GLM 5.1
LMArena Text: non-English	1448	1417	GLM 5.1
LMArena Text: Chinese	1515	1470	GLM 5.1
LMArena Text: German	1467	1455	GLM 5.1
LMArena Text: Japanese	1435	1415	GLM 5.1
LMArena Text: Korean	1424	1415	GLM 5.1
LMArena Text: French	1470	1458	GLM 5.1
LMArena Text: Spanish	1468	1446	GLM 5.1
LMArena Text: Russian	1454	1427	GLM 5.1
LMArena Text: Polish	1449	1405	GLM 5.1
LMArena Text: multi-turn	1473	1434	GLM 5.1
LMArena Text: longer queries	1467	1436	GLM 5.1
LMArena Text: writing and language	1454	1419	GLM 5.1
LMArena Text: entertainment and media	1442	1402	GLM 5.1
LMArena Vision: English	Not measured	1263	Only GPT-5.6 Luna measured
LMArena Vision: Chinese	Not measured	1294	Only GPT-5.6 Luna measured
LMArena Vision: reading text	Not measured	1264	Only GPT-5.6 Luna measured
LMArena Vision: humor	Not measured	1190	Only GPT-5.6 Luna measured
LMArena Vision: creative writing	Not measured	1257	Only GPT-5.6 Luna measured
LMArena Document	Not measured	1457	Only GPT-5.6 Luna measured
Neither model has a result on the other 10 boards here

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

Image generation benchmarks for GLM 5.1 and GPT-5.6 Luna
Benchmark	GLM 5.1	GPT-5.6 Luna	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 5.1$0.0036Fits in one request

GPT-5.6 Luna$0.0008Fits in one request

GPT-5.6 Luna costs less

Repository review

50K input + 3K output tokens

GLM 5.1$0.083Fits in one request

GPT-5.6 Luna$0.014Fits in one request

GPT-5.6 Luna costs less

Agent loop

200K input + 10K output tokens

GLM 5.1$0.324Exceeds the context window

GPT-5.6 Luna$0.052Fits in one request

GPT-5.6 Luna 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 5.1 and GPT-5.6 Luna
Specification	Z.ai GLM 5.1	OpenAI GPT-5.6 Luna
Maker	Z.ai	OpenAI
Weights	Open weights	No public weights listed
Released	April 7, 2026	July 9, 2026
Context window	205K	1.05M
Input $/Mtok	$1.40	$0.20
Output $/Mtok	$4.40	$1.20
Coding index	49.2	58.0
Independent measurements behind it	3	6
Cost per solved task	$0.60	$0.04
Source	OpenRouter listing	OpenRouter listing

Questions

Is GLM 5.1 better than GPT-5.6 Luna for coding?

Pick GPT-5.6 Luna for coding: it scores 58.0 on the Vibe Coding Index against 49.2 for GLM 5.1. Pick GLM 5.1 for work measured by LMArena Text: coding or LMArena Text: software and IT, where it leads.

Which is cheaper, GLM 5.1 or GPT-5.6 Luna?

GLM 5.1 costs $1.40 per million input tokens and $4.40 per million output tokens; GPT-5.6 Luna costs $0.20 and $1.20. Per solved SWE-bench Verified task, GLM 5.1 costs $0.60 and GPT-5.6 Luna $0.04.

Which has the bigger context window, GLM 5.1 or GPT-5.6 Luna?

GPT-5.6 Luna, with 1.05M tokens against 205K.

How many benchmarks is the GLM 5.1 vs GPT-5.6 Luna comparison based on?

73 benchmarks have a result for both models as of October 22, 2026. GLM 5.1's coding index rests on 3 independent benchmarks and GPT-5.6 Luna's on 6. Where only one model has a result, the page says so instead of naming a winner.

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GLM 5.1 or GPT-5.6 Luna: which to pick

Which one for your work

Coding

Intelligence

Agentic work

Reasoning

Math

Knowledge

Web design

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

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