Gemini 4 Carbon vs GPT-5.6 Terra: pricing and benchmarks
Both charge $2.00 per 1M input tokens. Gemini 4 Carbon is 17% cheaper on output tokens ($10.00 vs $12.00 per 1M). On our document Q&A workload (50,000 questions a month), Gemini 4 Carbon costs $1,100 a month versus $1,160 for GPT-5.6 Terra, 5% less. Epoch AI has not published a capability index score for Gemini 4 Carbon yet.
Which should you choose?
Epoch AI has not published a capability index score for Gemini 4 Carbon yet.
Gemini 4 Carbon costs $4.00 per 1M tokens (3:1 input-to-output mix) vs $4.50 for GPT-5.6 Terra, 11% less.
Pricing and specs
| Gemini 4 Carbon | GPT-5.6 Terra | |
|---|---|---|
| Provider | OpenAI | |
| API model ID | gemini-4-carbon | gpt-5.6-terra |
| Input / 1M tokens | $2.00 | $2.00 |
| Cached input / 1M tokens | $0.10 | $0.20 |
| Output / 1M tokens | $10.00 | $12.00 |
| Long-context rates | — | $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 | 50% off |
Benchmarks
| Gemini 4 Carbon | GPT-5.6 Terra | |
|---|---|---|
| Epoch Capabilities Index | — | 159.4 |
| GPQA Diamond· Science reasoning | — | 93.3% |
| FrontierMath (Tiers 1–3)· Advanced math | — | 86.0% |
| SimpleQA Verified· Factual accuracy | — | 43.2% |
| ARC-AGI-2· Abstract reasoning | — | 83.9% |
| DeepSWE· Coding | — | 69.6% |
| APEX-Agents· Agentic work | — | 58.2% |
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 4 Carbon | GPT-5.6 Terra | Difference |
|---|---|---|---|
Support chatbot 100,000 replies a month, ~1,500 input tokens (system prompt + history) and ~400 output tokens each. | $700.00 | $780.00 | Gemini 4 Carbon 10% cheaper |
Document Q&A (RAG) 50,000 questions a month with ~8,000 tokens of retrieved context and ~600 output tokens each. | $1,100 | $1,160 | Gemini 4 Carbon 5% cheaper |
Coding agent 10,000 agent steps a month, ~40,000 input tokens each (70% read from the prompt cache) and ~2,000 output tokens. | $468.00 | $536.00 | Gemini 4 Carbon 13% cheaper |
Cached chatbot The same 100,000-reply support chatbot, but 60% of each prompt (system prompt + conversation history) is served from the prompt cache. | $529.00 | $618.00 | Gemini 4 Carbon 14% cheaper |
Meeting notes 10,000 meetings a month summarized from ~12,000-token transcripts, ~1,000 output tokens each. | $340.00 | $360.00 | Gemini 4 Carbon 6% cheaper |
Bulk translation 200,000 short translations a month, ~800 input and ~800 output tokens each. | $1,920 | $2,240 | Gemini 4 Carbon 14% cheaper |
Content moderation 1,000,000 classifications a month, ~400 input tokens and ~80 output tokens each. | $1,600 | $1,760 | Gemini 4 Carbon 9% cheaper |
Article drafting 300 long-form articles a month written from a ~4,000-token brief and outline, ~5,000 output tokens each. | $17.40 | $20.40 | Gemini 4 Carbon 15% cheaper |
Code review bot 30,000 pull-request reviews a month, ~5,000 input tokens each (30% cached repository context) and ~700 output tokens. | $424.50 | $471.00 | Gemini 4 Carbon 10% cheaper |
Invoice extraction 100,000 documents a month parsed into structured JSON, ~1,200 input and ~250 output tokens each. | $490.00 | $540.00 | Gemini 4 Carbon 9% cheaper |
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 4 Carbon vs GPT-5.6 Terra cost calculator
- $1,100/mo$0.02 / req
- GPT-5.6 TerraOpenAI$1,160/mo$0.02 / req
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 4 Carbon pricing notes
Google’s most capable reasoning model, for sustained agentic coding, multimodal knowledge work and scientific reasoning.
- Introductory price through November 30, 2026. From December 1, 2026: $4 input, $0.20 cached, $20 output per 1M tokens.
- Not available on the Gemini API free tier.
- Output price includes thinking tokens.
- Max output is 65,536 tokens by default and up to 1,048,576 with long decode.
- Implicit caching only; explicit context caching is not supported.
- Priority inference costs 1.8x the standard rate.
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 4 Carbon cheaper than GPT-5.6 Terra?
- Both charge $2.00 per 1M input tokens. Gemini 4 Carbon is 17% cheaper on output tokens ($10.00 vs $12.00 per 1M). On our document Q&A workload (50,000 questions a month), Gemini 4 Carbon costs $1,100 a month versus $1,160 for GPT-5.6 Terra, 5% less.
- Which is more capable, Gemini 4 Carbon or GPT-5.6 Terra?
- Epoch AI has not published a capability index score for Gemini 4 Carbon yet.
- How much does Gemini 4 Carbon cost per 1M tokens?
- Gemini 4 Carbon costs $2.00 per 1M input tokens and $10.00 per 1M output tokens, and $0.10 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 4 Carbon or GPT-5.6 Terra?
- GPT-5.6 Terra has the larger context window: 1.05M tokens versus 1.05M for Gemini 4 Carbon.