Gemini 3.8 Flash vs GPT-5.6 Sol: pricing and benchmarks
Gemini 3.8 Flash is 81% cheaper on input tokens ($0.75 vs $4.00 per 1M). Gemini 3.8 Flash is 81% cheaper on output tokens ($3.75 vs $20.00 per 1M). On our document Q&A workload (50,000 questions a month), Gemini 3.8 Flash costs $412.50 a month versus $2,200 for GPT-5.6 Sol, 81% less. Roughly tied. Gemini 3.8 Flash scores 156.5 and GPT-5.6 Sol scores 161.8 on the Epoch Capabilities Index, and their confidence intervals overlap.
Prices verified September 14, 2026.
Which should you choose?
Roughly tied. Gemini 3.8 Flash scores 156.5 and GPT-5.6 Sol scores 161.8 on the Epoch Capabilities Index, and their confidence intervals overlap.
About even on DeepSWE: 73.8% for Gemini 3.8 Flash and 72.7% for GPT-5.6 Sol.
GPT-5.6 Sol scores 89.1% on FrontierMath (Tiers 1–3) vs 68.4% for Gemini 3.8 Flash.
Gemini 3.8 Flash costs $1.50 per 1M tokens (3:1 input-to-output mix) vs $8.00 for GPT-5.6 Sol, 81% less.
Gemini 3.8 Flash delivers statistically similar overall capability for 81% less.
Pricing and specs
| Gemini 3.8 Flash | GPT-5.6 Sol | |
|---|---|---|
| Provider | OpenAI | |
| API model ID | gemini-3.8-flash | gpt-5.6-sol |
| Input / 1M tokens | $0.75 | $4.00 |
| Cached input / 1M tokens | $0.075 | $0.40 |
| Output / 1M tokens | $3.75 | $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 3.8 Flash | GPT-5.6 Sol | |
|---|---|---|
| Epoch Capabilities Index | 156.5 | 161.8 |
| GPQA Diamond· Science reasoning | 93.9% | 91.3% |
| FrontierMath (Tiers 1–3)· Advanced math | 68.4% | 89.1% |
| SimpleQA Verified· Factual accuracy | 69.7% | 69.7% |
| ARC-AGI-2· Abstract reasoning | — | 92.5% |
| DeepSWE· Coding | 73.8% | 72.7% |
| APEX-Agents· Agentic work | — | 40.0% |
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 3.8 Flash | GPT-5.6 Sol | Difference |
|---|---|---|---|
Support chatbot 100,000 replies a month, ~1,500 input tokens (system prompt + history) and ~400 output tokens each. | $262.50 | $1,400 | Gemini 3.8 Flash 81% cheaper |
Document Q&A (RAG) 50,000 questions a month with ~8,000 tokens of retrieved context and ~600 output tokens each. | $412.50 | $2,200 | Gemini 3.8 Flash 81% 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. | $186.00 | $992.00 | Gemini 3.8 Flash 81% 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 3.8 Flash vs GPT-5.6 Sol cost calculator
- $412.50/mo$0.0083 / request
- GPT-5.6 SolOpenAI$2,200/mo$0.04 / 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 3.8 Flash pricing notes
Google’s newest Flash model, with thinking, tool use and a 1M-token context window.
- Introductory price through December 31, 2026. From January 1, 2027: $1.50 input, $0.15 cached, $7.50 output per 1M tokens.
- Output price includes thinking tokens.
- 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 3.8 Flash cheaper than GPT-5.6 Sol?
- Gemini 3.8 Flash is 81% cheaper on input tokens ($0.75 vs $4.00 per 1M). Gemini 3.8 Flash is 81% cheaper on output tokens ($3.75 vs $20.00 per 1M). On our document Q&A workload (50,000 questions a month), Gemini 3.8 Flash costs $412.50 a month versus $2,200 for GPT-5.6 Sol, 81% less.
- Which is more capable, Gemini 3.8 Flash or GPT-5.6 Sol?
- Roughly tied. Gemini 3.8 Flash scores 156.5 and GPT-5.6 Sol scores 161.8 on the Epoch Capabilities Index, and their confidence intervals overlap.
- How much does Gemini 3.8 Flash cost per 1M tokens?
- Gemini 3.8 Flash costs $0.75 per 1M input tokens and $3.75 per 1M output tokens, and $0.075 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 3.8 Flash or GPT-5.6 Sol?
- GPT-5.6 Sol has the larger context window: 1.05M tokens versus 1.05M for Gemini 3.8 Flash.