Gemini 3.8 Flash vs GPT-6 Astra: pricing and benchmarks
Gemini 3.8 Flash is 93% cheaper on input tokens ($0.75 vs $10.00 per 1M). Gemini 3.8 Flash is 93% cheaper on output tokens ($3.75 vs $50.00 per 1M). On our document Q&A workload (50,000 questions a month), Gemini 3.8 Flash costs $412.50 a month versus $5,500 for GPT-6 Astra, 93% less. GPT-6 Astra scores 166.3 on the Epoch Capabilities Index vs 156.5 for Gemini 3.8 Flash.
Prices verified September 14, 2026.
Which should you choose?
GPT-6 Astra scores 166.3 on the Epoch Capabilities Index vs 156.5 for Gemini 3.8 Flash.
About even on DeepSWE: 73.8% for Gemini 3.8 Flash and 74.1% for GPT-6 Astra.
GPT-6 Astra scores 93.7% 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 $20.00 for GPT-6 Astra, 93% less.
A trade-off: GPT-6 Astra is 9.8 ECI points more capable but costs 13.3x as much as Gemini 3.8 Flash.
Pricing and specs
| Gemini 3.8 Flash | GPT-6 Astra | |
|---|---|---|
| Provider | OpenAI | |
| API model ID | gemini-3.8-flash | gpt-6-astra |
| Input / 1M tokens | $0.75 | $10.00 |
| Cached input / 1M tokens | $0.075 | $1.00 |
| Output / 1M tokens | $3.75 | $50.00 |
| Long-context rates | — | $20.00 in / $75.00 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-6 Astra | |
|---|---|---|
| Epoch Capabilities Index | 156.5 | 166.3 |
| GPQA Diamond· Science reasoning | 93.9% | 94.4% |
| FrontierMath (Tiers 1–3)· Advanced math | 68.4% | 93.7% |
| SimpleQA Verified· Factual accuracy | 69.7% | 75.6% |
| ARC-AGI-2· Abstract reasoning | — | 95.0% |
| DeepSWE· Coding | 73.8% | 74.1% |
| APEX-Agents· Agentic work | — | 46.7% |
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-6 Astra | Difference |
|---|---|---|---|
Support chatbot 100,000 replies a month, ~1,500 input tokens (system prompt + history) and ~400 output tokens each. | $262.50 | $3,500 | Gemini 3.8 Flash 93% cheaper |
Document Q&A (RAG) 50,000 questions a month with ~8,000 tokens of retrieved context and ~600 output tokens each. | $412.50 | $5,500 | Gemini 3.8 Flash 93% 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 | $2,480 | Gemini 3.8 Flash 93% 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-6 Astra cost calculator
- $412.50/mo$0.0083 / request
- GPT-6 AstraOpenAI$5,500/mo$0.11 / 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-6 Astra pricing notes
OpenAI’s most capable model, built for the hardest end-to-end reasoning and coding work.
- Cache writes are billed at $12.50 per 1M tokens.
- Fast mode costs 2x the standard rate; Flex costs half.
- Regional (data residency) endpoints add a 10% uplift.
Frequently asked questions
- Is Gemini 3.8 Flash cheaper than GPT-6 Astra?
- Gemini 3.8 Flash is 93% cheaper on input tokens ($0.75 vs $10.00 per 1M). Gemini 3.8 Flash is 93% cheaper on output tokens ($3.75 vs $50.00 per 1M). On our document Q&A workload (50,000 questions a month), Gemini 3.8 Flash costs $412.50 a month versus $5,500 for GPT-6 Astra, 93% less.
- Which is more capable, Gemini 3.8 Flash or GPT-6 Astra?
- GPT-6 Astra scores 166.3 on the Epoch Capabilities Index vs 156.5 for Gemini 3.8 Flash.
- 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-6 Astra cost per 1M tokens?
- GPT-6 Astra costs $10.00 per 1M input tokens and $50.00 per 1M output tokens, and $1.00 per 1M cached input tokens on OpenAI’s standard tier.
- Which has the larger context window, Gemini 3.8 Flash or GPT-6 Astra?
- GPT-6 Astra has the larger context window: 1.05M tokens versus 1.05M for Gemini 3.8 Flash.