Gemini 3.1 Pro vs GPT-5.6 Terra: pricing and benchmarks
Both charge $2.00 per 1M input tokens. Both charge $12.00 per 1M output tokens. On our document Q&A workload both models cost $1,160 a month. Roughly tied. Gemini 3.1 Pro scores 155.0 and GPT-5.6 Terra scores 159.1 on the Epoch Capabilities Index, and their confidence intervals overlap.
Prices verified September 14, 2026.
Which should you choose?
Roughly tied. Gemini 3.1 Pro scores 155.0 and GPT-5.6 Terra scores 159.1 on the Epoch Capabilities Index, and their confidence intervals overlap.
GPT-5.6 Terra scores 69.6% on DeepSWE vs 11.7% for Gemini 3.1 Pro.
GPT-5.6 Terra scores 86.0% on FrontierMath (Tiers 1–3) vs 59.6% for Gemini 3.1 Pro.
Both cost $4.50 per 1M tokens at a 3:1 input-to-output mix.
Pricing and specs
| Gemini 3.1 Pro | GPT-5.6 Terra | |
|---|---|---|
| Provider | OpenAI | |
| API model ID | gemini-3.1-pro-preview | gpt-5.6-terra |
| Input / 1M tokens | $2.00 | $2.00 |
| Cached input / 1M tokens | $0.20 | $0.20 |
| Output / 1M tokens | $12.00 | $12.00 |
| Long-context rates | $4.00 in / $18.00 out above 200K prompt tokens | $4.00 in / $18.00 out on long-context requests |
| Context window | 1.05M tokens | 1.05M tokens |
| Max output | 66K tokens | 128K tokens |
| Batch discount | — | 50% off |
Benchmarks
| Gemini 3.1 Pro | GPT-5.6 Terra | |
|---|---|---|
| Epoch Capabilities Index | 155.0 | 159.1 |
| GPQA Diamond· Science reasoning | 92.6% | 91.1% |
| FrontierMath (Tiers 1–3)· Advanced math | 59.6% | 86.0% |
| SimpleQA Verified· Factual accuracy | 73.5% | 43.2% |
| ARC-AGI-2· Abstract reasoning | 77.1% | 83.9% |
| DeepSWE· Coding | 11.7% | 69.6% |
| APEX-Agents· Agentic work | 33.5% | — |
Source: Epoch AI, best recorded result per model (CC BY 4.0). A dash means no published score. See all benchmarks
Monthly cost for real workloads
| Workload | Gemini 3.1 Pro | GPT-5.6 Terra | Difference |
|---|---|---|---|
Support chatbot 100,000 replies a month, ~1,500 input tokens (system prompt + history) and ~400 output tokens each. | $780.00 | $780.00 | Same |
Document Q&A (RAG) 50,000 questions a month with ~8,000 tokens of retrieved context and ~600 output tokens each. | $1,160 | $1,160 | Same |
Coding agent 10,000 agent steps a month, ~40,000 input tokens each (70% read from the prompt cache) and ~2,000 output tokens. | $536.00 | $536.00 | Same |
Estimates use standard list prices and ignore cache-write surcharges. Different tokenizers can count the same text differently, so test with your own prompts.
Gemini 3.1 Pro vs GPT-5.6 Terra cost calculator
- $1,160/mo$0.02 / request
- Gemini 3.1 ProGoogle$1,160/mo$0.02 / request
Standard-tier list prices. Long-context rates apply automatically where the provider publishes a threshold. Excludes cache-write surcharges, taxes, batch and volume discounts.
Gemini 3.1 Pro pricing notes
Google’s Gemini 3.1 Pro model, currently offered as a preview.
- Prompts over 200K tokens are billed at $4 input / $18 output per 1M tokens.
- No free tier on the Gemini API.
- Output price includes thinking tokens.
GPT-5.6 Terra pricing notes
The GPT-5.6 model that balances intelligence and cost.
- Cache writes are billed at $2.50 per 1M tokens.
- Fast mode costs 2x the standard rate; Flex costs half.
Frequently asked questions
- Is Gemini 3.1 Pro cheaper than GPT-5.6 Terra?
- Both charge $2.00 per 1M input tokens. Both charge $12.00 per 1M output tokens. On our document Q&A workload both models cost $1,160 a month.
- Which is more capable, Gemini 3.1 Pro or GPT-5.6 Terra?
- Roughly tied. Gemini 3.1 Pro scores 155.0 and GPT-5.6 Terra scores 159.1 on the Epoch Capabilities Index, and their confidence intervals overlap.
- How much does Gemini 3.1 Pro cost per 1M tokens?
- Gemini 3.1 Pro costs $2.00 per 1M input tokens and $12.00 per 1M output tokens, and $0.20 per 1M cached input tokens on Google’s standard tier.
- How much does GPT-5.6 Terra cost per 1M tokens?
- GPT-5.6 Terra costs $2.00 per 1M input tokens and $12.00 per 1M output tokens, and $0.20 per 1M cached input tokens on OpenAI’s standard tier.
- Which has the larger context window, Gemini 3.1 Pro or GPT-5.6 Terra?
- GPT-5.6 Terra has the larger context window: 1.05M tokens versus 1.05M for Gemini 3.1 Pro.