Hermes-4-405B vs Sonar
API pricing, benchmark indices and specs — updated 19 October 2026.
NousResearch · A · Open weights
Params
405.9 B
Context
131,072
30d
1 K
llama3 licence · conditional
perplexity · B · API-only
Input / 1M
$1.00
Output / 1M
$1.00
AA index
7.7
proprietary · 127.1K context
Specification comparison
Differences are highlighted; identical values are muted.
| Specification | Hermes-4-405B | Sonar |
|---|---|---|
| Deployment | Open weights · also via API | API-only (closed weights) |
| Parameters | 405.9 B | n/a — API-only |
| Architecture | LlamaForCausalLM | n/a — API-only |
| Context length | 131,072 | 127,072 |
| Licence | llama3 | Proprietary |
| Commercial use | Conditional | Per API terms |
| Languages | 1 | n/a — API-only |
| Downloads 30d | 1,216 | n/a — API-only |
| Downloads all time | 8 K | n/a — API-only |
| Quantizations on the Hub | SAFETENSORS | n/a — API-only |
| Gated | No | n/a — API-only |
| First seen on the Hub | 2025-08-06 | n/a — API-only |
| API input price / 1M tokens | $1.00 | $1.00 |
| API output price / 1M tokens | $3.00 | $1.00 |
| Est. cost per 1M input + 1M output tokens | $4.00 | $2.00 |
| Cached input / 1M tokens | — | — |
| AA Intelligence Index | 7.5 | 7.7 |
| AA Coding Index | — | — |
| AA Agentic Index | — | — |
| Max output tokens | 117,964 | 114,364 |
| API providers | 1 | 1 |
| Tool calling | No | No |
| Reasoning mode | Yes | No |
API cost
Estimated cost of 1M input + 1M output tokens via OpenRouter
Hermes-4-405B
$4.00
Sonar
$2.00
Sonar is 2.0× cheaper at list price.
VRAM side by side
On RTX 4090 · 24 GB · 8K context unless noted
Hermes-4-405B · fp16 @ 128K ctx
1,867.4 GB / 24 GB