Model comparison
GLM-4.5 vs GLM-5.1
GLM-5.1 is the stronger model overall, scoring 47.8 to 42.0 on the Noometry Index. GLM-4.5 costs 2.1× less per token, which makes it the better buy when GLM-5.1's lead doesn't matter for your workload.
Last verified . 20 shared benchmarks.
Summary
- They share 20 benchmarks with published results for both. GLM-4.5 scores higher in 0 categories and GLM-5.1 in 8 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in knowledge, where GLM-5.1 leads 54.9 to 35.9.
- The biggest single-benchmark swing is WeirdML: 40.6% for GLM-4.5 and 57.1% for GLM-5.1.
- GLM-4.5 is cheaper at $0.60 / $2.20 per million input/output tokens, against $1.40 / $4.40 for GLM-5.1.
- GLM-5.1 accepts more context: 200K tokens versus 131K.
Side by side
| GLM-4.5 | GLM-5.1 | |
|---|---|---|
| Provider | Z.ai (Zhipu) | Z.ai (Zhipu) |
| Noometry Index | 42.0 | 47.8 |
| Released | 2025-07-27 | 2026-04-07 |
| Weights | Open | Open |
| Context window | 131K | 200K |
| Max output | 98K | 131K |
| Input $ / M tokens | $0.60 | $1.40 |
| Output $ / M tokens | $2.20 | $4.40 |
| Results tracked | 27 | 41 |
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Category by category
Coding GLM-5.1 leads
GLM-4.5: 41.4 (#125), GLM-5.1: 48.7 (#55)
| Benchmark | GLM-4.5 | GLM-5.1 |
|---|---|---|
| WeirdML | 40.6% | 57.1% |
| LMArena Coding | 1434 | 1485 |
| ALE-Bench | 344.82 | 887.1 |
| SWE-bench Verified | — | 74.2% |
| SWE-bench Verified (bash only) | 54.2% | — |
| LMArena WebDev | — | 1508 |
| SciCode | — | 43.8% |
| AlgoTune | 1.52 | — |
Agentic & Tool Use Not comparable
GLM-4.5: —, GLM-5.1: 24.9 (#113)
| Benchmark | GLM-4.5 | GLM-5.1 |
|---|---|---|
| APEX-Agents | — | 40.9% |
| ExploitBench | — | 18.1% |
| GBAEval | — | 0% |
| Vending-Bench 2 | — | 5,634 |
Reasoning GLM-5.1 leads
GLM-4.5: 28.6 (#100), GLM-5.1: 39.1 (#60)
| Benchmark | GLM-4.5 | GLM-5.1 |
|---|---|---|
| LMArena Hard Prompts | 1429 | 1472 |
| SimpleBench | — | 55.1% |
| Kagi LLM Benchmark | 57.9% | — |
| NYT Connections (extended) | — | 77.7% |
| CritPt | — | 4.6% |
| Chess Puzzles | — | 19% |
| Thematic Generalization | — | 69.8% |
| Epoch Capabilities Index | — | 149.84 |
Math GLM-5.1 leads
GLM-4.5: 39.0 (#116), GLM-5.1: 49.7 (#60)
| Benchmark | GLM-4.5 | GLM-5.1 |
|---|---|---|
| LMArena Math | 1427 | 1473 |
| FrontierMath (Tiers 1-3) | — | 36.8% |
| MathArena Final-Answer Competitions | — | 67.1% |
| OTIS Mock AIME 2024-2025 | — | 93.3% |
| ProofBench | — | 22.2% |
| FrontierMath (Feb 2025 set) | — | 33.4% |
| FrontierMath Tier 4 (v1) | — | 12.5% |
Knowledge GLM-5.1 leads
GLM-4.5: 35.9 (#179), GLM-5.1: 54.9 (#50)
| Benchmark | GLM-4.5 | GLM-5.1 |
|---|---|---|
| LMArena Expert | 1433 | 1476 |
| GPQA Diamond | — | 89.9% |
| Humanity's Last Exam | 8.3% | — |
| SimpleQA Verified | — | 34% |
| Confabulations | 11.3% | — |
Multilingual GLM-5.1 leads
GLM-4.5: 52.8 (#77), GLM-5.1: 55.0 (#36)
| Benchmark | GLM-4.5 | GLM-5.1 |
|---|---|---|
| LMArena Non-English | 1417 | 1447 |
| LMArena Chinese | 1465 | 1515 |
| LMArena French | 1418 | 1474 |
| LMArena German | 1407 | 1465 |
| LMArena Japanese | 1415 | 1434 |
| LMArena Korean | 1380 | 1418 |
| LMArena Russian | 1414 | 1454 |
| LMArena Spanish | 1454 | 1469 |
Instruction Following GLM-5.1 leads
GLM-4.5: 74.1 (#104), GLM-5.1: 76.3 (#42)
| Benchmark | GLM-4.5 | GLM-5.1 |
|---|---|---|
| LMArena Instruction Following | 1404 | 1451 |
Long Context GLM-5.1 leads
GLM-4.5: 38.2 (#201), GLM-5.1: 44.9 (#53)
| Benchmark | GLM-4.5 | GLM-5.1 |
|---|---|---|
| LMArena Longer Query | 1412 | 1466 |
| Fiction.LiveBench | 58.3% | — |
Writing & Preference GLM-5.1 leads
GLM-4.5: 57.5 (#127), GLM-5.1: 66.9 (#31)
| Benchmark | GLM-4.5 | GLM-5.1 |
|---|---|---|
| LMArena Text | 1430 | 1461 |
| LMArena Creative Writing | 1395 | 1453 |
| EQ-Bench Creative Writing | 1343 | 1592 |
| LMArena Multi-Turn | 1415 | 1472 |
| Short-Story Creative Writing | 73.4% | — |
Frequently asked questions
Is GLM-4.5 better than GLM-5.1?
GLM-5.1 is the stronger model overall, scoring 47.8 to 42.0 on the Noometry Index. GLM-4.5 costs 2.1× less per token, which makes it the better buy when GLM-5.1's lead doesn't matter for your workload.
Which is cheaper, GLM-4.5 or GLM-5.1?
GLM-4.5 is cheaper. It lists at $0.60 per million input tokens and $2.20 per million output tokens; GLM-5.1 lists at $1.40 and $4.40.
Is GLM-4.5 or GLM-5.1 better for coding?
GLM-5.1 scores higher on coding benchmarks: 48.7 versus 41.4 in the Noometry coding category.
Which has the bigger context window?
GLM-5.1 does, with 200K tokens against 131K.
How many benchmarks do GLM-4.5 and GLM-5.1 share?
20 benchmarks have published results for both models. GLM-4.5 has 27 scored results on Noometry and GLM-5.1 has 41.