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Gemini 3.8 Flash vs GLM 5.3 Flash

Gemini 3.8 Flash leads GLM 5.3 Flash on coding, 61.6 to 57.7 on the Vibe Coding Index, and GLM 5.3 Flash costs 7.5x less per output token ($0.50 vs $3.75 per million). Updated October 22, 2026; 102 benchmarks have a result for both.

Replace Gemini 3.8 Flash Replace GLM 5.3 Flash
Gemini 3.8 FlashGoogle
Coding
61.6
Overall
69.0
Output $/M
$3.75
86
GLM 5.3 FlashZ.ai
Coding
57.7
Overall
66.0
Output $/M
$0.50
15
vs boards won of 102 shared, 1 tied

Gemini 3.8 Flash or GLM 5.3 Flash: which to pick

Pick Gemini 3.8 Flash for coding: it scores 61.6 on the Vibe Coding Index against 57.7 for GLM 5.3 Flash.

Pick GLM 5.3 Flash for output tokens 7.5x cheaper ($0.50 vs $3.75 per million) and a lower cost per solved task ($0.02 against $2.74).

Model AGemini 3.8 FlashGoogle61.6/1006 independent benchmarks$2.74 per solved taskModel BGLM 5.3 FlashZ.ai57.7/1006 independent benchmarks$0.02 per solved task
Shared results
102
Gemini 3.8 Flash only
26
GLM 5.3 Flash only
0
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.

At a glance

Coding index
Gemini 3.8 Flash 61.6 from 6 benchmarks, GLM 5.3 Flash 57.7 from 6 benchmarks.
Widest category
Reasoning, 11.0 points apart on average over 15 shared benchmarks.
Widest single gap
Vibe Code Bench (Vals AI): Gemini 3.8 Flash 78.7% against GLM 5.3 Flash 30.8%, 47.9 points apart on a 0 to 100 scale.
Output price
Gemini 3.8 Flash $3.75 against GLM 5.3 Flash $0.50 per million output tokens, 7.5x apart.
Context window
Both take 1.05M tokens.

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
CategoryGemini 3.8 FlashBarsGLM 5.3 FlashTies
Coding185
Intelligence11
Agentic work93
Reasoning150
Math60
Knowledge61
Web design531 tie
General262
All shared boards86151 tie
CodingLike-for-likeSix of these boards feed the Vibe Coding Index185
Coding benchmarks for Gemini 3.8 Flash and GLM 5.3 Flash
BenchmarkGemini 3.8 FlashGLM 5.3 FlashLeader
LiveBench coding82.2%80.6%Gemini 3.8 Flash
LMArena WebDev15851607GLM 5.3 Flash
AA Coding Index76.371.5Gemini 3.8 Flash
LiveCodeBench (Vals AI)89.5%80.5%Gemini 3.8 Flash
SWE-bench Verified (Vals AI)80.0%92.0%GLM 5.3 Flash
Terminal-Bench 4 (Vals AI)19.7%37.4%GLM 5.3 Flash
Vibe Code Bench (Vals AI)78.7%30.8%Gemini 3.8 Flash
Code migration (Vals AI)36.5%20.5%Gemini 3.8 Flash
ProgramBench (Vals AI)1.0%0.0%Gemini 3.8 Flash
IOI (Vals AI)56.9%52.5%Gemini 3.8 Flash
Terminal-Bench 2.1 (Vals AI)81.3%62.9%Gemini 3.8 Flash
SWE-bench Multimodal (Vals AI)40.8%Not measuredOnly Gemini 3.8 Flash measured
Vibe Code Bench 1-100 (Vals AI)18.8%16.0%Gemini 3.8 Flash
SkillsBench (Vals AI)58.0%40.2%Gemini 3.8 Flash
CyberBench (Vals AI)43.8%67.9%GLM 5.3 Flash
SciCode56.6%51.6%Gemini 3.8 Flash
FrontierCode41.2%31.8%Gemini 3.8 Flash
FrontierSWE19.6%18.1%Gemini 3.8 Flash
WeirdML84.8%Not measuredOnly Gemini 3.8 Flash measured
ALE-Bench1269.7303.6Gemini 3.8 Flash
LMArena Text: coding15081507Gemini 3.8 Flash
LMArena Text: software and IT15071500Gemini 3.8 Flash
LMArena WebDev: React15771624GLM 5.3 Flash
LMArena WebDev: HTML16161577Gemini 3.8 Flash
LMArena WebDev: from an image15931578Gemini 3.8 Flash
SciCode12.3%Not measuredOnly Gemini 3.8 Flash measured
Neither model has a result on the other 13 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index11
Intelligence benchmarks for Gemini 3.8 Flash and GLM 5.3 Flash
BenchmarkGemini 3.8 FlashGLM 5.3 FlashLeader
AA Intelligence Index40.941.8GLM 5.3 Flash
Epoch Capabilities Index157.4153.1Gemini 3.8 Flash
Agentic workLike-for-likePublic boards, shown as published, kept out of the index93
Agentic work benchmarks for Gemini 3.8 Flash and GLM 5.3 Flash
BenchmarkGemini 3.8 FlashGLM 5.3 FlashLeader
AA Agentic Index40.250.9GLM 5.3 Flash
Design Arena: agents building web apps1238Not measuredOnly Gemini 3.8 Flash measured
Design Arena: agents building full-stack apps1244Not measuredOnly Gemini 3.8 Flash measured
Design Arena: agents building mobile apps1236Not measuredOnly Gemini 3.8 Flash measured
Design Arena: agents building Android apps1078Not measuredOnly Gemini 3.8 Flash measured
Design Arena: agents building Godot games1273Not measuredOnly Gemini 3.8 Flash measured
Design Arena: PowerPoint slides1153Not measuredOnly Gemini 3.8 Flash measured
Design Arena: spreadsheets1022Not measuredOnly Gemini 3.8 Flash measured
LiveBench research79.1%70.1%Gemini 3.8 Flash
LiveBench browser64.0%84.0%GLM 5.3 Flash
LiveBench long agentic30.1%28.4%Gemini 3.8 Flash
SREBench (Vals AI)11.1%0.8%Gemini 3.8 Flash
Finance Agent (Vals AI)61.4%57.9%Gemini 3.8 Flash
Tax Agent Bench (Vals AI)32.1%31.6%Gemini 3.8 Flash
Legal Research Bench (Vals AI)38.9%45.2%GLM 5.3 Flash
Harvey's Legal Agent Benchmark (Vals AI)12.1%10.4%Gemini 3.8 Flash
Excel Modeling Benchmark (Vals AI)72.2%55.9%Gemini 3.8 Flash
BioMysteryBench (Vals AI)62.2%Not measuredOnly Gemini 3.8 Flash measured
Terminal-Bench-Science (Vals AI)8.6%2.9%Gemini 3.8 Flash
Vals Science Index35.8%Not measuredOnly Gemini 3.8 Flash measured
Time Horizon Index (Vals AI)18.8%Not measuredOnly Gemini 3.8 Flash measured
CUA-bench (Vals AI)4.2%Not measuredOnly Gemini 3.8 Flash measured
APEX-Agents64.3%52.8%Gemini 3.8 Flash
Remote Labor Index5.8%Not measuredOnly Gemini 3.8 Flash measured
Vending-Bench 2$5,094Not measuredOnly Gemini 3.8 Flash measured
Neither model has a result on the other 16 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index150
Reasoning benchmarks for Gemini 3.8 Flash and GLM 5.3 Flash
BenchmarkGemini 3.8 FlashGLM 5.3 FlashLeader
GPQA Diamond94.4%86.4%Gemini 3.8 Flash
LiveBench reasoning89.3%77.6%Gemini 3.8 Flash
MysteryMechanism (Vals AI)36.5%Not measuredOnly Gemini 3.8 Flash measured
MMMU Pro (Vals AI)89.1%86.0%Gemini 3.8 Flash
GPQA Diamond (Artificial Analysis run)95.3%91.2%Gemini 3.8 Flash
Humanity's Last Exam (Artificial Analysis run)47.8%39.9%Gemini 3.8 Flash
GPQA Diamond (Epoch AI run)95.4%90.2%Gemini 3.8 Flash
ARC-AGI98.5%91.0%Gemini 3.8 Flash
ARC-AGI-289.2%65.8%Gemini 3.8 Flash
Chess puzzles58.0%21.0%Gemini 3.8 Flash
Mystery game puzzles47.0%8.0%Gemini 3.8 Flash
LMArena Text: hard prompts15091490Gemini 3.8 Flash
LMArena Text: expert15261511Gemini 3.8 Flash
LMArena Text: hard prompts in English15041488Gemini 3.8 Flash
LMArena Vision: diagrams13451317Gemini 3.8 Flash
LMArena Vision: homework13511318Gemini 3.8 Flash
Neither model has a result on the other 6 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index60
Math benchmarks for Gemini 3.8 Flash and GLM 5.3 Flash
BenchmarkGemini 3.8 FlashGLM 5.3 FlashLeader
OTIS Mock AIME98.9%93.9%Gemini 3.8 Flash
FrontierMath, tiers 1 to 368.4%55.8%Gemini 3.8 Flash
FrontierMath, tier 422.0%17.1%Gemini 3.8 Flash
ProofBench48.0%21.0%Gemini 3.8 Flash
LMArena Text: math15321503Gemini 3.8 Flash
LMArena Text: mathematical work15191497Gemini 3.8 Flash
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index61
Knowledge benchmarks for Gemini 3.8 Flash and GLM 5.3 Flash
BenchmarkGemini 3.8 FlashGLM 5.3 FlashLeader
MMLU Pro90.2%86.1%Gemini 3.8 Flash
LegalBench (Vals AI)87.0%83.9%Gemini 3.8 Flash
TaxEval (Vals AI)74.5%75.6%GLM 5.3 Flash
MortgageTax (Vals AI)65.3%Not measuredOnly Gemini 3.8 Flash measured
MedCode (Vals AI)48.1%Not measuredOnly Gemini 3.8 Flash measured
SimpleQA Verified69.7%Not measuredOnly Gemini 3.8 Flash measured
LMArena Text: science15231484Gemini 3.8 Flash
LMArena Text: medicine and healthcare15081475Gemini 3.8 Flash
LMArena Text: legal and government14971473Gemini 3.8 Flash
LMArena Text: business and finance14791460Gemini 3.8 Flash
FACTS Benchmark Suite69.4%Not measuredOnly Gemini 3.8 Flash measured
Neither model has a result on the other 7 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index53
Web design benchmarks for Gemini 3.8 Flash and GLM 5.3 Flash
BenchmarkGemini 3.8 FlashGLM 5.3 FlashLeader
Design Arena: websites13001272Gemini 3.8 Flash
Design Arena: UI components13161316Tie
Design Arena: game dev13041278Gemini 3.8 Flash
Design Arena: data viz12701262Gemini 3.8 Flash
Design Arena: 3D12941316GLM 5.3 Flash
Design Arena: all code categories13031282Gemini 3.8 Flash
Design Arena: SVG12961285Gemini 3.8 Flash
Design Arena: ASCII art12621267GLM 5.3 Flash
LiveBench design72.7%77.2%GLM 5.3 Flash
GeneralLike-for-likePublic boards, shown as published, kept out of the index262
General benchmarks for Gemini 3.8 Flash and GLM 5.3 Flash
BenchmarkGemini 3.8 FlashGLM 5.3 FlashLeader
Vals Index56.0%50.9%Gemini 3.8 Flash
LiveBench data analysis54.0%76.4%GLM 5.3 Flash
Public Benefits Bench (Vals AI)65.3%Not measuredOnly Gemini 3.8 Flash measured
SAGE (Vals AI)35.1%Not measuredOnly Gemini 3.8 Flash measured
MedScribe (Vals AI)84.5%88.9%GLM 5.3 Flash
Long context reasoning (AA-LCR)84.0%80.0%Gemini 3.8 Flash
DTBench95.7%Not measuredOnly Gemini 3.8 Flash measured
LMCA52.9%Not measuredOnly Gemini 3.8 Flash measured
Surface Evolver Bench76.9%52.5%Gemini 3.8 Flash
Furniture assembly31.7%Not measuredOnly Gemini 3.8 Flash measured
LMArena Text14991471Gemini 3.8 Flash
LMArena Text: instruction following14921478Gemini 3.8 Flash
LMArena Text: creative writing14881441Gemini 3.8 Flash
LMArena Vision13151294Gemini 3.8 Flash
LMArena Text: English14981474Gemini 3.8 Flash
LMArena Text: non-English14911462Gemini 3.8 Flash
LMArena Text: Chinese15531531Gemini 3.8 Flash
LMArena Text: German15011462Gemini 3.8 Flash
LMArena Text: Japanese15071444Gemini 3.8 Flash
LMArena Text: Korean14641436Gemini 3.8 Flash
LMArena Text: French14961491Gemini 3.8 Flash
LMArena Text: Spanish14871475Gemini 3.8 Flash
LMArena Text: Russian15141465Gemini 3.8 Flash
LMArena Text: Polish14971450Gemini 3.8 Flash
LMArena Text: multi-turn15031469Gemini 3.8 Flash
LMArena Text: longer queries15071481Gemini 3.8 Flash
LMArena Text: writing and language14941455Gemini 3.8 Flash
LMArena Text: entertainment and media14801440Gemini 3.8 Flash
LMArena Vision: English13181295Gemini 3.8 Flash
LMArena Vision: Chinese14161363Gemini 3.8 Flash
LMArena Vision: reading text13331299Gemini 3.8 Flash
LMArena Vision: humor13211279Gemini 3.8 Flash
LMArena Vision: creative writing12991270Gemini 3.8 Flash
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 Gemini 3.8 Flash and GLM 5.3 Flash
BenchmarkGemini 3.8 FlashGLM 5.3 FlashLeader
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

Gemini 3.8 Flash$0.0026Fits in one request
GLM 5.3 Flash$0.0004Fits in one request

GLM 5.3 Flash costs less

Repository review

50K input + 3K output tokens

Gemini 3.8 Flash$0.049Fits in one request
GLM 5.3 Flash$0.0090Fits in one request

GLM 5.3 Flash costs less

Agent loop

200K input + 10K output tokens

Gemini 3.8 Flash$0.188Fits in one request
GLM 5.3 Flash$0.035Fits in one request

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 Gemini 3.8 Flash and GLM 5.3 Flash
SpecificationGoogle Gemini 3.8 FlashZ.ai GLM 5.3 Flash
MakerGoogleZ.ai
WeightsNo public weights listedOpen weights
ReleasedSeptember 2, 2026August 26, 2026
Context window1.05M1.05M
Input $/Mtok$0.75$0.15
Output $/Mtok$3.75$0.50
Coding index61.657.7
Independent measurements behind it66
Cost per solved task$2.74$0.02
SourceOpenRouter listingOpenRouter listing

Questions

Is Gemini 3.8 Flash better than GLM 5.3 Flash for coding?

Pick Gemini 3.8 Flash for coding: it scores 61.6 on the Vibe Coding Index against 57.7 for GLM 5.3 Flash. Pick GLM 5.3 Flash for output tokens 7.5x cheaper ($0.50 vs $3.75 per million) and a lower cost per solved task ($0.02 against $2.74).

Which is cheaper, Gemini 3.8 Flash or GLM 5.3 Flash?

Gemini 3.8 Flash costs $0.75 per million input tokens and $3.75 per million output tokens; GLM 5.3 Flash costs $0.15 and $0.50. Per solved SWE-bench Verified task, Gemini 3.8 Flash costs $2.74 and GLM 5.3 Flash $0.02.

Which has the bigger context window, Gemini 3.8 Flash or GLM 5.3 Flash?

Neither: both take 1.05M tokens.

How many benchmarks is the Gemini 3.8 Flash vs GLM 5.3 Flash comparison based on?

102 benchmarks have a result for both models as of October 22, 2026. Gemini 3.8 Flash's coding index rests on 6 independent benchmarks and GLM 5.3 Flash's on 6. Where only one model has a result, the page says so instead of naming a winner.

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