GPT-5.6 Terra vs Gemini 3.1 Pro
Side-by-side comparison of API pricing, specs, benchmarks, and capabilities
| Specification |
by OpenAI
|
by Google
|
|---|---|---|
| Overview | ||
| Status | Current flagship | Current flagship |
| Released | Jul 9, 2026 | Feb 19, 2026 |
| Pricing per million tokens | ||
| Input | $2.00/Mtok | $2.00/Mtok |
| Output | $12.00/Mtok | $12.00/Mtok |
| Blended avg | $4.50/Mtok | $4.50/Mtok |
| Cached input | $0.200/Mtok | $0.200/Mtok |
| Specifications | ||
| Context window | 1M tokens | 2M tokens |
| Parameters | Proprietary | Proprietary |
| Speed (TPS) | — | — |
| Modalities | ||
| Input |
textimage
|
textimageaudiovideo
|
| Benchmarks source: Vellum LLM Leaderboard | ||
| Avg benchmark score | 87.7 | 74.8 |
| Perf / dollar | 19.5 | 16.6 |
| GPQA Diamond | 92.9 | 94.3 |
| Terminal-Bench 2.1 | 82.5 | 70.3 |
| MCP Atlas | — | 69.2 |
| BrowseComp | — | 85.9 |
| OSWorld-Verified | — | 76.2 |
| Humanity's Last Exam | — | 44.4 |
| ARC-AGI 2 | — | 77.1 |
| HumanEval | — | 80.6 |
| Independent composite scores each on its own scale — not part of the average above | ||
| AA Intelligence Index | 56.6 | 47.7 |
| AA Agentic Index | 50.2 | 23 |
| AA-Omniscience Index (−100–100) | 0.1 | 31.9 |
| GDPval-AA v2 | 1565.5 ELO | — |
| LMSYS Chatbot Arena | — | 1486.7 ELO |
| Providers | ||
| Available from |
OpenAI — $2.00/$12.00/Mtok
|
Google — $2.00/$12.00/Mtok
|
Cost at scale
1M tokens · 50/50 input/output| Volume | GPT-5.6 Terra | Gemini 3.1 Pro | Savings |
|---|---|---|---|
| 1M tokens | $4.5 | $4.5 | $0 (0%) |
| 10M tokens | $45 | $45 | $0 (0%) |
| 100M tokens | $450 | $450 | $0 (0%) |
| 1000M tokens | $4500 | $4500 | $0 (0%) |
When to pick which
distilled from the pricing and spec data above- raw capability matters more than price: 87.7 vs 74.8 average benchmark score
- you need the longer context: 2M tokens vs 1M (1.9×)
Price movement
recorded changes since we began tracking each model · last checked Aug 28, 2026| Model | Changes | Latest move | Old → new $/M |
|---|---|---|---|
| GPT-5.6 Terra | 1 | price cut on Aug 1, 2026 | $2.5/$15 → $2/$12/Mtok |
| Gemini 3.1 Pro | 0 | — no move | Stable since we began tracking — no change recorded |
The cheaper option here — GPT-5.6 Terra costs $4.50/Mtok blended on OpenAI.
Summary
GPT-5.6 Terra by OpenAI costs $2.00/Mtok input and $12.00/Mtok output, with a 1M-token context window. It supports text, image input.
Gemini 3.1 Pro by Google costs $2.00/Mtok input and $12.00/Mtok output, with a 2M-token context window. It supports text, image, audio, video input.
On benchmarks, GPT-5.6 Terra scores higher (87.7 vs 74.8) on average. In terms of value, GPT-5.6 Terra has better performance per dollar (19.5 vs 16.6).
Note: Pricing is per million tokens. Actual costs vary with usage patterns, prompt caching, and batch discounts. Always verify against official provider pricing pages.