Gemini 4 Carbon vs GPT-5.6 Sol: pricing and benchmarks
Gemini 4 Carbon is 50% cheaper on input tokens ($2.00 vs $4.00 per 1M). Gemini 4 Carbon is 50% cheaper on output tokens ($10.00 vs $20.00 per 1M). On our document Q&A workload (50,000 questions a month), Gemini 4 Carbon costs $1,100 a month versus $2,200 for GPT-5.6 Sol, 50% 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 $8.00 for GPT-5.6 Sol, 50% less.
Pricing and specs
| Gemini 4 Carbon | GPT-5.6 Sol | |
|---|---|---|
| Provider | OpenAI | |
| API model ID | gemini-4-carbon | gpt-5.6-sol |
| Input / 1M tokens | $2.00 | $4.00 |
| Cached input / 1M tokens | $0.10 | $0.40 |
| Output / 1M tokens | $10.00 | $20.00 |
| Long-context rates | — | $8.00 in / $30.00 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 Sol | |
|---|---|---|
| Epoch Capabilities Index | — | 161.7 |
| GPQA Diamond· Science reasoning | — | 93.5% |
| FrontierMath (Tiers 1–3)· Advanced math | — | 89.1% |
| SimpleQA Verified· Factual accuracy | — | 69.7% |
| ARC-AGI-2· Abstract reasoning | — | 92.5% |
| DeepSWE· Coding | — | 72.7% |
| APEX-Agents· Agentic work | — | 51.4% |
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 Sol | Difference |
|---|---|---|---|
Support chatbot 100,000 replies a month, ~1,500 input tokens (system prompt + history) and ~400 output tokens each. | $700.00 | $1,400 | Gemini 4 Carbon 50% cheaper |
Document Q&A (RAG) 50,000 questions a month with ~8,000 tokens of retrieved context and ~600 output tokens each. | $1,100 | $2,200 | Gemini 4 Carbon 50% 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 | $992.00 | Gemini 4 Carbon 53% 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 | $1,076 | Gemini 4 Carbon 51% cheaper |
Meeting notes 10,000 meetings a month summarized from ~12,000-token transcripts, ~1,000 output tokens each. | $340.00 | $680.00 | Gemini 4 Carbon 50% cheaper |
Bulk translation 200,000 short translations a month, ~800 input and ~800 output tokens each. | $1,920 | $3,840 | Gemini 4 Carbon 50% cheaper |
Content moderation 1,000,000 classifications a month, ~400 input tokens and ~80 output tokens each. | $1,600 | $3,200 | Gemini 4 Carbon 50% 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 | $34.80 | Gemini 4 Carbon 50% 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 | $858.00 | Gemini 4 Carbon 51% cheaper |
Invoice extraction 100,000 documents a month parsed into structured JSON, ~1,200 input and ~250 output tokens each. | $490.00 | $980.00 | Gemini 4 Carbon 50% 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 Sol cost calculator
- $1,100/mo$0.02 / req
- GPT-5.6 SolOpenAI$2,200/mo$0.04 / 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 Sol pricing notes
OpenAI’s flagship GPT-5.6 model for complex professional work.
- Promotional pricing, available at least through November 21, 2026.
- Cache writes are billed at $5 per 1M tokens.
- Regional (data residency) endpoints add a 10% uplift.
Frequently asked questions
- Is Gemini 4 Carbon cheaper than GPT-5.6 Sol?
- Gemini 4 Carbon is 50% cheaper on input tokens ($2.00 vs $4.00 per 1M). Gemini 4 Carbon is 50% cheaper on output tokens ($10.00 vs $20.00 per 1M). On our document Q&A workload (50,000 questions a month), Gemini 4 Carbon costs $1,100 a month versus $2,200 for GPT-5.6 Sol, 50% less.
- Which is more capable, Gemini 4 Carbon or GPT-5.6 Sol?
- 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 Sol cost per 1M tokens?
- GPT-5.6 Sol costs $4.00 per 1M input tokens and $20.00 per 1M output tokens, and $0.40 per 1M cached input tokens on OpenAI’s standard tier.
- Which has the larger context window, Gemini 4 Carbon or GPT-5.6 Sol?
- GPT-5.6 Sol has the larger context window: 1.05M tokens versus 1.05M for Gemini 4 Carbon.