Gemini 3.8 Flash vs GLM 5.3
GLM 5.3 leads Gemini 3.8 Flash on coding, 70.6 to 61.6 on the Vibe Coding Index, at about the same output price ($4.40 vs $3.75 per million). Updated October 22, 2026; 99 benchmarks have a result for both.
Gemini 3.8 Flash or GLM 5.3: which to pick
Pick GLM 5.3 for coding: it scores 70.6 on the Vibe Coding Index against 61.6 for Gemini 3.8 Flash.
Pick Gemini 3.8 Flash for output tokens 1.2x cheaper ($3.75 vs $4.40 per million) and work measured by AA Coding Index or LiveCodeBench (Vals AI), where it leads.
- Shared results
- 99
- Gemini 3.8 Flash only
- 29
- GLM 5.3 only
- 1
- 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
GLM 5.3
GLM 5.3 scores 70.6 against 61.6.
6 benchmarks behind each score
Intelligence
AA Intelligence Index
GLM 5.3
GLM 5.3 leads, 44.8 against 40.9.
Same board, both measured
Agentic work
AA Agentic Index
GLM 5.3
GLM 5.3 leads, 53.1 against 40.2.
Same board, both measured
Reasoning
GPQA Diamond
Gemini 3.8 Flash
Gemini 3.8 Flash leads, 94.4% against 88.1%.
Same board, both measured
Knowledge
MMLU Pro
Gemini 3.8 Flash
Gemini 3.8 Flash leads, 90.2% against 86.8%.
Same board, both measured
Web design
Design Arena: websites
Gemini 3.8 Flash
Gemini 3.8 Flash leads, 1300 against 1295.
Same board, both measured
General
Vals Index
GLM 5.3
GLM 5.3 leads, 59.7% against 56.0%.
Same board, both measured
Long documents
Listed context window
No call
Both take 1.05M tokens.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Gemini 3.8 Flash
Gemini 3.8 Flash $0.0026, GLM 5.3 $0.0036 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
GLM 5.3
Gemini 3.8 Flash $2.74, GLM 5.3 $0.36.
Published attempt cost and pass rate
At a glance
- Coding index
- Gemini 3.8 Flash 61.6 from 6 benchmarks, GLM 5.3 70.6 from 6 benchmarks.
- Widest category
- Agentic work, 11.8 points apart on average over 15 shared benchmarks.
- Widest single gap
- LiveBench browser: Gemini 3.8 Flash 64.0% against GLM 5.3 0.0%, 64.0 points apart on a 0 to 100 scale.
- Output price
- Gemini 3.8 Flash $3.75 against GLM 5.3 $4.40 per million output tokens, 1.2x 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.
| Category | Gemini 3.8 Flash | Bars | GLM 5.3 | Ties |
|---|---|---|---|---|
| Coding | 10 | 13 | ||
| Intelligence | 1 | 1 | ||
| Agentic work | 8 | 7 | ||
| Reasoning | 11 | 0 | ||
| Math | 3 | 3 | ||
| Knowledge | 9 | 0 | ||
| Web design | 5 | 4 | ||
| General | 18 | 6 | ||
| All shared boards | 65 | 34 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index1013
| Benchmark | Gemini 3.8 Flash | GLM 5.3 | Leader |
|---|---|---|---|
| LiveBench coding | 82.2% | 82.8% | GLM 5.3 |
| LMArena WebDev | 1585 | 1621 | GLM 5.3 |
| AA Coding Index | 76.3 | 74.8 | Gemini 3.8 Flash |
| LiveCodeBench (Vals AI) | 89.5% | 80.5% | Gemini 3.8 Flash |
| SWE-bench Verified (Vals AI) | 80.0% | 95.4% | GLM 5.3 |
| Terminal-Bench 4 (Vals AI) | 19.7% | 38.9% | GLM 5.3 |
| Vibe Code Bench (Vals AI) | 78.7% | 78.1% | Gemini 3.8 Flash |
| Code migration (Vals AI) | 36.5% | 44.2% | GLM 5.3 |
| ProgramBench (Vals AI) | 1.0% | 1.5% | GLM 5.3 |
| IOI (Vals AI) | 56.9% | 68.4% | GLM 5.3 |
| Terminal-Bench 2.1 (Vals AI) | 81.3% | 71.5% | Gemini 3.8 Flash |
| SWE-bench Multimodal (Vals AI) | 40.8% | Not measured | Only Gemini 3.8 Flash measured |
| Vibe Code Bench 1-100 (Vals AI) | 18.8% | 20.0% | GLM 5.3 |
| SkillsBench (Vals AI) | 58.0% | 47.5% | Gemini 3.8 Flash |
| CyberBench (Vals AI) | 43.8% | 72.1% | GLM 5.3 |
| SciCode | 56.6% | 59.0% | GLM 5.3 |
| FrontierCode | 41.2% | 40.1% | Gemini 3.8 Flash |
| FrontierSWE | 19.6% | 30.2% | GLM 5.3 |
| WeirdML | 84.8% | 75.4% | Gemini 3.8 Flash |
| ALE-Bench | 1269.7 | 1317.4 | GLM 5.3 |
| LMArena Text: coding | 1508 | 1497 | Gemini 3.8 Flash |
| LMArena Text: software and IT | 1507 | 1493 | Gemini 3.8 Flash |
| LMArena WebDev: React | 1577 | 1641 | GLM 5.3 |
| LMArena WebDev: HTML | 1616 | 1595 | Gemini 3.8 Flash |
| LMArena WebDev: from an image | 1593 | Not measured | Only Gemini 3.8 Flash measured |
| SciCode | 12.3% | Not measured | Only 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
| Benchmark | Gemini 3.8 Flash | GLM 5.3 | Leader |
|---|---|---|---|
| AA Intelligence Index | 40.9 | 44.8 | GLM 5.3 |
| Epoch Capabilities Index | 157.4 | 156.0 | Gemini 3.8 Flash |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index87
| Benchmark | Gemini 3.8 Flash | GLM 5.3 | Leader |
|---|---|---|---|
| AA Agentic Index | 40.2 | 53.1 | GLM 5.3 |
| Design Arena: agents building web apps | 1238 | Not measured | Only Gemini 3.8 Flash measured |
| Design Arena: agents building full-stack apps | 1244 | Not measured | Only Gemini 3.8 Flash measured |
| Design Arena: agents building mobile apps | 1236 | 1194 | Gemini 3.8 Flash |
| Design Arena: agents building Android apps | 1078 | Not measured | Only Gemini 3.8 Flash measured |
| Design Arena: agents building Godot games | 1273 | Not measured | Only Gemini 3.8 Flash measured |
| Design Arena: HTML slides | Not measured | 1189 | Only GLM 5.3 measured |
| Design Arena: PowerPoint slides | 1153 | 1230 | GLM 5.3 |
| Design Arena: spreadsheets | 1022 | Not measured | Only Gemini 3.8 Flash measured |
| LiveBench research | 79.1% | 73.2% | Gemini 3.8 Flash |
| LiveBench browser | 64.0% | 0.0% | Gemini 3.8 Flash |
| LiveBench long agentic | 30.1% | 35.9% | GLM 5.3 |
| SREBench (Vals AI) | 11.1% | 9.2% | Gemini 3.8 Flash |
| Finance Agent (Vals AI) | 61.4% | 55.8% | Gemini 3.8 Flash |
| Tax Agent Bench (Vals AI) | 32.1% | 39.7% | GLM 5.3 |
| Legal Research Bench (Vals AI) | 38.9% | 49.0% | GLM 5.3 |
| Harvey's Legal Agent Benchmark (Vals AI) | 12.1% | 14.6% | GLM 5.3 |
| Excel Modeling Benchmark (Vals AI) | 72.2% | 56.3% | Gemini 3.8 Flash |
| BioMysteryBench (Vals AI) | 62.2% | Not measured | Only Gemini 3.8 Flash measured |
| Terminal-Bench-Science (Vals AI) | 8.6% | 5.7% | Gemini 3.8 Flash |
| Vals Science Index | 35.8% | Not measured | Only Gemini 3.8 Flash measured |
| Time Horizon Index (Vals AI) | 18.8% | Not measured | Only Gemini 3.8 Flash measured |
| CUA-bench (Vals AI) | 4.2% | Not measured | Only Gemini 3.8 Flash measured |
| APEX-Agents | 64.3% | 56.6% | Gemini 3.8 Flash |
| Remote Labor Index | 5.8% | Not measured | Only Gemini 3.8 Flash measured |
| Vending-Bench 2 | $5,094 | $8,164 | GLM 5.3 |
| Neither model has a result on the other 15 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index110
| Benchmark | Gemini 3.8 Flash | GLM 5.3 | Leader |
|---|---|---|---|
| GPQA Diamond | 94.4% | 88.1% | Gemini 3.8 Flash |
| LiveBench reasoning | 89.3% | 85.8% | Gemini 3.8 Flash |
| MysteryMechanism (Vals AI) | 36.5% | 23.0% | Gemini 3.8 Flash |
| MMMU Pro (Vals AI) | 89.1% | Not measured | Only Gemini 3.8 Flash measured |
| GPQA Diamond (Artificial Analysis run) | 95.3% | 91.7% | Gemini 3.8 Flash |
| Humanity's Last Exam (Artificial Analysis run) | 47.8% | 42.3% | Gemini 3.8 Flash |
| GPQA Diamond (Epoch AI run) | 95.4% | 90.9% | Gemini 3.8 Flash |
| ARC-AGI | 98.5% | Not measured | Only Gemini 3.8 Flash measured |
| ARC-AGI-2 | 89.2% | Not measured | Only Gemini 3.8 Flash measured |
| Chess puzzles | 58.0% | 37.0% | Gemini 3.8 Flash |
| Mystery game puzzles | 47.0% | 33.0% | Gemini 3.8 Flash |
| LMArena Text: hard prompts | 1509 | 1490 | Gemini 3.8 Flash |
| LMArena Text: expert | 1526 | 1514 | Gemini 3.8 Flash |
| LMArena Text: hard prompts in English | 1504 | 1496 | Gemini 3.8 Flash |
| LMArena Vision: diagrams | 1345 | Not measured | Only Gemini 3.8 Flash measured |
| LMArena Vision: homework | 1351 | Not measured | Only Gemini 3.8 Flash measured |
| Neither model has a result on the other 6 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index33
| Benchmark | Gemini 3.8 Flash | GLM 5.3 | Leader |
|---|---|---|---|
| OTIS Mock AIME | 98.9% | 91.1% | Gemini 3.8 Flash |
| FrontierMath, tiers 1 to 3 | 68.4% | 68.8% | GLM 5.3 |
| FrontierMath, tier 4 | 22.0% | 29.3% | GLM 5.3 |
| ProofBench | 48.0% | 49.0% | GLM 5.3 |
| LMArena Text: math | 1532 | 1495 | Gemini 3.8 Flash |
| LMArena Text: mathematical work | 1519 | 1497 | Gemini 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 index90
| Benchmark | Gemini 3.8 Flash | GLM 5.3 | Leader |
|---|---|---|---|
| MMLU Pro | 90.2% | 86.8% | Gemini 3.8 Flash |
| LegalBench (Vals AI) | 87.0% | 84.8% | Gemini 3.8 Flash |
| TaxEval (Vals AI) | 74.5% | 72.4% | Gemini 3.8 Flash |
| MortgageTax (Vals AI) | 65.3% | Not measured | Only Gemini 3.8 Flash measured |
| MedCode (Vals AI) | 48.1% | 42.9% | Gemini 3.8 Flash |
| SimpleQA Verified | 69.7% | 41.0% | Gemini 3.8 Flash |
| LMArena Text: science | 1523 | 1498 | Gemini 3.8 Flash |
| LMArena Text: medicine and healthcare | 1508 | 1481 | Gemini 3.8 Flash |
| LMArena Text: legal and government | 1497 | 1473 | Gemini 3.8 Flash |
| LMArena Text: business and finance | 1479 | 1459 | Gemini 3.8 Flash |
| FACTS Benchmark Suite | 69.4% | Not measured | Only 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 index54
| Benchmark | Gemini 3.8 Flash | GLM 5.3 | Leader |
|---|---|---|---|
| Design Arena: websites | 1300 | 1295 | Gemini 3.8 Flash |
| Design Arena: UI components | 1316 | 1314 | Gemini 3.8 Flash |
| Design Arena: game dev | 1304 | 1311 | GLM 5.3 |
| Design Arena: data viz | 1270 | 1260 | Gemini 3.8 Flash |
| Design Arena: 3D | 1294 | 1332 | GLM 5.3 |
| Design Arena: all code categories | 1303 | 1304 | GLM 5.3 |
| Design Arena: SVG | 1296 | 1294 | Gemini 3.8 Flash |
| Design Arena: ASCII art | 1262 | 1208 | Gemini 3.8 Flash |
| LiveBench design | 72.7% | 77.3% | GLM 5.3 |
GeneralLike-for-likePublic boards, shown as published, kept out of the index186
| Benchmark | Gemini 3.8 Flash | GLM 5.3 | Leader |
|---|---|---|---|
| Vals Index | 56.0% | 59.7% | GLM 5.3 |
| LiveBench data analysis | 54.0% | 70.2% | GLM 5.3 |
| Public Benefits Bench (Vals AI) | 65.3% | 68.5% | GLM 5.3 |
| SAGE (Vals AI) | 35.1% | Not measured | Only Gemini 3.8 Flash measured |
| MedScribe (Vals AI) | 84.5% | 88.8% | GLM 5.3 |
| Long context reasoning (AA-LCR) | 84.0% | 79.7% | Gemini 3.8 Flash |
| DTBench | 95.7% | 87.7% | Gemini 3.8 Flash |
| LMCA | 52.9% | 55.5% | GLM 5.3 |
| Surface Evolver Bench | 76.9% | Not measured | Only Gemini 3.8 Flash measured |
| Furniture assembly | 31.7% | Not measured | Only Gemini 3.8 Flash measured |
| LMArena Text | 1499 | 1474 | Gemini 3.8 Flash |
| LMArena Text: instruction following | 1492 | 1479 | Gemini 3.8 Flash |
| LMArena Text: creative writing | 1488 | 1458 | Gemini 3.8 Flash |
| LMArena Vision | 1315 | Not measured | Only Gemini 3.8 Flash measured |
| LMArena Text: English | 1498 | 1482 | Gemini 3.8 Flash |
| LMArena Text: non-English | 1491 | 1459 | Gemini 3.8 Flash |
| LMArena Text: Chinese | 1553 | 1532 | Gemini 3.8 Flash |
| LMArena Text: German | 1501 | 1488 | Gemini 3.8 Flash |
| LMArena Text: Japanese | 1507 | 1460 | Gemini 3.8 Flash |
| LMArena Text: Korean | 1464 | 1460 | Gemini 3.8 Flash |
| LMArena Text: French | 1496 | 1503 | GLM 5.3 |
| LMArena Text: Spanish | 1487 | 1462 | Gemini 3.8 Flash |
| LMArena Text: Russian | 1514 | 1469 | Gemini 3.8 Flash |
| LMArena Text: Polish | 1497 | 1466 | Gemini 3.8 Flash |
| LMArena Text: multi-turn | 1503 | 1472 | Gemini 3.8 Flash |
| LMArena Text: longer queries | 1507 | 1483 | Gemini 3.8 Flash |
| LMArena Text: writing and language | 1494 | 1469 | Gemini 3.8 Flash |
| LMArena Text: entertainment and media | 1480 | 1447 | Gemini 3.8 Flash |
| LMArena Vision: English | 1318 | Not measured | Only Gemini 3.8 Flash measured |
| LMArena Vision: Chinese | 1416 | Not measured | Only Gemini 3.8 Flash measured |
| LMArena Vision: reading text | 1333 | Not measured | Only Gemini 3.8 Flash measured |
| LMArena Vision: humor | 1321 | Not measured | Only Gemini 3.8 Flash measured |
| LMArena Vision: creative writing | 1299 | Not measured | Only Gemini 3.8 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
| Benchmark | Gemini 3.8 Flash | GLM 5.3 | 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
Gemini 3.8 Flash costs less
Repository review
50K input + 3K output tokens
Gemini 3.8 Flash costs less
Agent loop
200K input + 10K output tokens
Gemini 3.8 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.
| Specification | Google Gemini 3.8 Flash | Z.ai GLM 5.3 |
|---|---|---|
| Maker | Z.ai | |
| Weights | No public weights listed | Open weights |
| Released | September 2, 2026 | August 18, 2026 |
| Context window | 1.05M | 1.05M |
| Input $/Mtok | $0.75 | $1.40 |
| Output $/Mtok | $3.75 | $4.40 |
| Coding index | 61.6 | 70.6 |
| Independent measurements behind it | 6 | 6 |
| Cost per solved task | $2.74 | $0.36 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Gemini 3.8 Flash better than GLM 5.3 for coding?
Pick GLM 5.3 for coding: it scores 70.6 on the Vibe Coding Index against 61.6 for Gemini 3.8 Flash. Pick Gemini 3.8 Flash for output tokens 1.2x cheaper ($3.75 vs $4.40 per million) and work measured by AA Coding Index or LiveCodeBench (Vals AI), where it leads.
Which is cheaper, Gemini 3.8 Flash or GLM 5.3?
Gemini 3.8 Flash costs $0.75 per million input tokens and $3.75 per million output tokens; GLM 5.3 costs $1.40 and $4.40. Per solved SWE-bench Verified task, Gemini 3.8 Flash costs $2.74 and GLM 5.3 $0.36.
Which has the bigger context window, Gemini 3.8 Flash or GLM 5.3?
Neither: both take 1.05M tokens.
How many benchmarks is the Gemini 3.8 Flash vs GLM 5.3 comparison based on?
99 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's on 6. Where only one model has a result, the page says so instead of naming a winner.