Compare / head-to-head
GLM-4.5-AirvsGLM-5.1
GLM-5.1 leads 1 of 1 shared benchmark. GLM-4.5-Air is 4.5x cheaper per token. GLM-5.1 has the larger context window (200K tokens).
Benchmarks from cited public sources; pricing from official pages; status from official provider feeds.
Shared benchmarks
0 – 1
GLM-5.1 leads
Cheaper per token
GLM-4.5-Air
4.5x cheaper, input + output
Larger context
GLM-5.1
200K tokens
Provider uptime (30d)
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Z.ai
GLM-4.5-Air
Z.ai
text
Quality
Benchmark matrix
1 shared · 1 only GLM-4.5-Air · 6 only GLM-5.1| Benchmark | GLM-4.5-Air | GLM-5.1 | Δ | Edge |
|---|---|---|---|---|
| Reported by both · 1 | ||||
| LMArena Elo | 1383.6 ↗ | 1462.4 ↗ | -78.8 | GLM-5.1 |
| Only GLM-4.5-Air reports · 1 | ||||
| AIME 2025 | 83.3% ↗matharena ⚠ | not reported | — | — |
| Only GLM-5.1 reports · 6 | ||||
| GPQA Diamond | not reported | 89.9% ↗epoch | — | — |
| AIME 2026 | not reported | 95.8% ↗matharena ⚠ | — | — |
| FrontierMath Tiers 1-3 v2 (Epoch AI run) | not reported | 36.8% ↗epoch | — | — |
| OTIS Mock AIME 2024-2025 (Epoch AI run) | not reported | 93.3% ↗epoch | — | — |
| SimpleQA Verified | not reported | 34% ↗epoch | — | — |
| SWE-bench Verified (Epoch AI run) | not reported | 74.2% ↗epoch | — | — |
Scores tagged "epoch" or "matharena" are independent runs, used only where the lab has not published its own; ⚠ marks rows MathArena flags as released after the competition. Higher is better on every row. Δ is GLM-4.5-Air minus GLM-5.1 in the benchmark's own unit. "Not reported" means the lab has not published that figure; it is not a zero. ↗ opens the source.
Specs & pricing
Side by side
Official pricing pages and model cards| Spec | GLM-4.5-Air | GLM-5.1 | Edge |
|---|---|---|---|
| Context window | 128K tokens | 200K tokens | GLM-5.1 |
| Max output | 98K tokens | 131K tokens | GLM-5.1 |
| Input price / 1M | $0.2 ↗ | $1.4 ↗ | GLM-4.5-Air |
| Output price / 1M | $1.1 ↗ | $4.4 ↗ | GLM-4.5-Air |
| Cached input / 1M | $0.03 ↗ | $0.26 ↗ | GLM-4.5-Air |
| Input + output / 1M Lower is cheaper. List prices; batch, tool and regional fees excluded. | $1.3 | $5.8 | GLM-4.5-Air |
| Modalities | text | text | Tie |
| Released | — | 2026-04-07 | — |
| Cited benchmark scores | 2 | 7 | — |
Reliability
Z.ai status
Last 60 days · refreshed daily on this page · live on /statusMore matchups
GLM-4.5-Air vs …
Models sharing the most benchmarksMore matchups
GLM-5.1 vs …
Models sharing the most benchmarksBuilt by Respan
Which one wins on your data?
Public benchmarks are a starting point. Run GLM-4.5-Air and GLM-5.1 on your own prompts with Respan evals, or route to either through one gateway key with automatic failover.