Claude Sonnet 5.5 vs GPT-6.1 Terra
API pricing, benchmark indices and specs — updated 29 October 2026.
anthropic · A · API-only
Input / 1M
$2.00
Output / 1M
$10.00
AA index
54.5
proprietary · 1M context
openai · B · API-only
Input / 1M
$1.00
Output / 1M
$5.00
AA index
51.3
proprietary · 1.0M context
Specification comparison
Differences are highlighted; identical values are muted.
| Specification | Claude Sonnet 5.5 | GPT-6.1 Terra |
|---|---|---|
| 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 | 1,000,000 | 1,050,000 |
| 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 | $1.00 |
| API output price / 1M tokens | $10.00 | $5.00 |
| Est. cost per 1M input + 1M output tokens | $12.00 | $6.00 |
| Cached input / 1M tokens | $0.10 | $0.05 |
| AA Intelligence Index | 54.5 | 51.3 |
| AA Coding Index | — | — |
| AA Agentic Index | — | — |
| Max output tokens | 128,000 | 128,000 |
| API providers | 5 | 3 |
| Tool calling | Yes | Yes |
| Reasoning mode | Yes | Yes |
API cost
Estimated cost of 1M input + 1M output tokens via OpenRouter
Claude Sonnet 5.5
$12.00
GPT-6.1 Terra
$6.00
GPT-6.1 Terra is 2.0× cheaper at list price.