GPT-5.6 Terra vs Gemini 3.8 Flash
API pricing, benchmark indices and specs — updated 19 October 2026.
openai · A · API-only
Input / 1M
$2.00
Output / 1M
$12.00
AA index
42.1
proprietary · 1.0M context
google · B · API-only
Input / 1M
$0.83
Output / 1M
$4.13
AA index
40.9
proprietary · 1M context
Specification comparison
Differences are highlighted; identical values are muted.
| Specification | GPT-5.6 Terra | Gemini 3.8 Flash |
|---|---|---|
| Deployment | API-only (closed weights) | API-only (closed weights) |
| Parameters | n/a — API-only | n/a — API-only |
| Architecture | n/a — API-only | n/a — API-only |
| Context length | 1,050,000 | 1,048,576 |
| Licence | Proprietary | Proprietary |
| Commercial use | Per API terms | Per API terms |
| Languages | n/a — API-only | n/a — API-only |
| Downloads 30d | n/a — API-only | n/a — API-only |
| Downloads all time | n/a — API-only | n/a — API-only |
| Quantizations on the Hub | n/a — API-only | n/a — API-only |
| Gated | n/a — API-only | n/a — API-only |
| First seen on the Hub | n/a — API-only | n/a — API-only |
| API input price / 1M tokens | $2.00 | $0.83 |
| API output price / 1M tokens | $12.00 | $4.13 |
| Est. cost per 1M input + 1M output tokens | $14.00 | $4.95 |
| Cached input / 1M tokens | $0.20 | $0.083 |
| AA Intelligence Index | 42.1 | 40.9 |
| AA Coding Index | 76.7 | 76.3 |
| AA Agentic Index | 43.2 | 40.2 |
| Max output tokens | 128,000 | 65,536 |
| API providers | 3 | 2 |
| Tool calling | Yes | Yes |
| Reasoning mode | Yes | Yes |
API cost
Estimated cost of 1M input + 1M output tokens via OpenRouter
GPT-5.6 Terra
$14.00
Gemini 3.8 Flash
$4.95
Gemini 3.8 Flash is 2.8× cheaper at list price.