GLM-5.1 vs Grok 4.20
API pricing, benchmark indices and specs — updated 19 October 2026.
x-ai · B · API-only
Input / 1M
$1.25
Output / 1M
$2.50
AA index
25.7
proprietary · 2M context
Specification comparison
Differences are highlighted; identical values are muted.
| Specification | GLM-5.1 | Grok 4.20 |
|---|---|---|
| Deployment | Open weights · also via API | API-only (closed weights) |
| Parameters | 753.9 B | n/a — API-only |
| Architecture | GlmMoeDsaForCausalLM | n/a — API-only |
| Context length | 202,752 | 2,000,000 |
| Licence | mit | Proprietary |
| Commercial use | Allowed | Per API terms |
| Languages | 2 | n/a — API-only |
| Downloads 30d | 626,063 | n/a — API-only |
| Downloads all time | 1.4 M | n/a — API-only |
| Quantizations on the Hub | SAFETENSORS | n/a — API-only |
| Gated | No | n/a — API-only |
| First seen on the Hub | 2026-04-03 | n/a — API-only |
| API input price / 1M tokens | $1.40 | $1.25 |
| API output price / 1M tokens | $4.40 | $2.50 |
| Est. cost per 1M input + 1M output tokens | $5.80 | $3.75 |
| Cached input / 1M tokens | $0.26 | $0.20 |
| AA Intelligence Index | 26.1 | 25.7 |
| AA Coding Index | 55.8 | — |
| AA Agentic Index | 23.9 | — |
| Max output tokens | 131,072 | 1,800,000 |
| API providers | 13 | 1 |
| Tool calling | Yes | Yes |
| Reasoning mode | Yes | Yes |
API cost
Estimated cost of 1M input + 1M output tokens via OpenRouter
GLM-5.1
$5.80
Grok 4.20
$3.75
Grok 4.20 is 1.5× cheaper at list price.
VRAM side by side
On RTX 4090 · 24 GB · 8K context unless noted
GLM-5.1 · fp16 @ 198K ctx
4,457.7 GB / 24 GB