GLM 5.1

GLM 5.1 is an open-weight model from zAI, released April 1, 2026. Its best result is #31 of 149 on LegalBench.

Release Date: Apr 1, 2026

Developer zAI Β πŸ‡¨πŸ‡³
Context Window 200k
Max Output Tokens 131k
Token Costs (in/out) $1.00/3.20
Weights Open
Input Modalities

Accuracy

53.02 %

Avg. Cost (In/Out)

$ 1.00 / $ 3.20

Latency

14 min 39 s

Vals Index
BenchmarksAccuracyRankings

25.77%

Β±4.09
45/75

44.79%

Β±0.61
53/76

27.89%

Β±3.12
47/75

41.60%

Β±2.12
51/106

72.27%

Β±2.06
88/108

61.84%

Β±1.26
27/48

71.19%

Β±0.90
82/145

31.46%

Β±4.55
68/110

84.52%

Β±1.82
52/138

81.38%

Β±1.06
63/143

84.39%

Β±0.43
31/149

86.90%

Β±0.33
37/138

0.00%

Β±0.00
46/63

76.40%

Β±1.90
40/88

56.93%

Β±1.35
47/75
Proprietary BenchmarksAcademic BenchmarksIndustry Partners
Vals
Default Provider : zAI
Temperature: 1
Top P: 0.95
Top K: Default
Max Output Tokens: 131,072

Updates

Apr 7, 2026

We’ve finished our evaluation of GLM 5.1 and it’s now the #1 open-weight model on the Vals Index, unseating Kimi K2.5, and ranking #6 overall on the index.

Key takeaways:

Eval settings: temperature=1, top_p=0.95, 131k max output tokens, run via the native GLM API. Context window: 200k tokens.

Congrats to the team at z.AI on the release!