GPT-6.1 Terra
GPT-6.1 Terra is an API-only (closed weights) language model from OpenAI, released October 26, 2026. The context window is 1.1M tokens. On the Epoch Capabilities Index it scores 167.7, rank 6 of 256 rated models. API price: $1 input / $5 output per million tokens.
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Lab
OpenAI
Released
October 26, 2026
Weights
API-only (closed weights)
Parameters
–
Context
1.1M
Price / M tokens
$1 / $5 in / out
Epoch ECI
167.7 #6
Strengths by category
ModelTape's 0–100 fit on Epoch AI benchmark results.
| Category | Score | Based on |
|---|---|---|
| Reasoning | 42.1 | SimpleBench, Mystery Game Puzzles |
| Math | 75.4 | OTIS Mock AIME 2024-2025, FrontierMath-Tiers-1-3-v2-Private, FrontierMath-Tier-4-v2-Private |
| Knowledge | 79.5 | GPQA diamond, SimpleQA Verified |
Benchmark results
| Benchmark (Epoch AI) | Score |
|---|---|
| OTIS Mock AIME | 100.0% |
| GPQA Diamond | 96.3% |
| FrontierMath (Tiers 1–3) | 95.7% |
| FrontierMath-Tier-4-v2-Private | 92.7% |
| EBR-bench | 78.1% |
| MirrorCode | 76.7% |
| Mystery Game Puzzles | 71.4% |
| Furniture Assembly | 70.2% |
| SimpleBench | 66.6% |
| SimpleQA Verified | 57.3% |
| SpireClimb | 22.3% |
Links
Announcement · Epoch AI benchmarks
Models with a similar score
Gemini 4 Carbon · GPT-6 Astra · Claude Opus 5.5 · GPT-6.1 Sol · Claude Fable 5.1 · Claude Sonnet 5.5 · Gemini 4 Argon · Claude Opus 5
More from OpenAI
GPT-6.1 Sol · GPT-6 Sol · GPT-6 Luna · GPT-6 Astra · GPT-5.6 Cyber · Daybreak Red · Daybreak Blue · GPT-5.6 Sol