Step-5-Preview vs GPT-5.6 Terra
API pricing, benchmark indices and specs — updated 19 October 2026.
openai · B · API-only
Input / 1M
$2.00
Output / 1M
$12.00
AA index
42.1
proprietary · 1.0M context
Specification comparison
Differences are highlighted; identical values are muted.
| Specification | Step-5-Preview | GPT-5.6 Terra |
|---|---|---|
| Deployment | Open weights · also via API | API-only (closed weights) |
| Parameters | 604.3 B | n/a — API-only |
| Architecture | Step5ForConditionalGeneration | n/a — API-only |
| Context length | 1,000,000 | 1,050,000 |
| Licence | other | Proprietary |
| Commercial use | Unknown | Per API terms |
| Languages | — | n/a — API-only |
| Downloads 30d | 2,467 | n/a — API-only |
| Downloads all time | 2 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 | 2026-09-20 | n/a — API-only |
| API input price / 1M tokens | $1.00 | $2.00 |
| API output price / 1M tokens | $2.70 | $12.00 |
| Est. cost per 1M input + 1M output tokens | $3.70 | $14.00 |
| Cached input / 1M tokens | $0.10 | $0.20 |
| AA Intelligence Index | 43.7 | 42.1 |
| AA Coding Index | — | 76.7 |
| AA Agentic Index | — | 43.2 |
| Max output tokens | 64,000 | 128,000 |
| API providers | 4 | 3 |
| Tool calling | Yes | Yes |
| Reasoning mode | Yes | Yes |
API cost
Estimated cost of 1M input + 1M output tokens via OpenRouter
Step-5-Preview
$3.70
GPT-5.6 Terra
$14.00
Step-5-Preview is 3.8× cheaper at list price.
VRAM side by side
On RTX 4090 · 24 GB · 8K context unless noted
Step-5-Preview · fp16
806.5 GB / 24 GB