Google's latest general-purpose Gemini model is a Flash release. Gemini 3.8 Flash, released on September 2, 2026, is what Google calls its best reasoning and coding model yet, and it is priced like a Flash model: $0.75 per million input tokens and $3.75 per million output tokens until the end of 2026, then $1.50 and $7.50. GPT-6 Astra, OpenAI's most capable model, lists at $10 and $50. Gemini 3.8 Flash accepts text, images, video, audio and PDFs across a 1,048,576-token input window. Astra takes text and images across 1,050,000 tokens.
Where they run matters too. Gemini 3.8 Flash is in the Gemini app, AI Mode in Google Search and Gemini in Google Sheets for Google AI Pro and Ultra subscribers. Astra is in ChatGPT for Plus, Pro, Business and Enterprise users, and OpenAI points it at computer use and template-bound documents. In OpenAI's launch table the two are close on GPQA Diamond and DeepSWE, and Astra leads clearly on Terminal-Bench 4.0. Google notes that 3.8 Flash can spend more tokens at higher effort levels. If you pay per token, run your real prompts through both in Omny and compare output and cost.
Which should you choose?
ChatGPT
GPT-6 Astra · 1M context
Pick it if
you need long terminal or computer-use tasks and documents that follow your templates.
Gemini
Gemini 3.8 Flash · 1M context
Pick it if
you want low per-token cost, video and audio input, or Gemini inside Search, Sheets and the Gemini app.
Gemini 3.8 Flash costs far less per token, accepts more input types and sits inside Google's apps. GPT-6 Astra is the pick for long terminal and computer-use tasks, where OpenAI's published results show a wide lead. On everyday prompts the gap is narrower, so compare both.
Questions
Is Gemini 3.8 Flash really cheaper than GPT-6 Astra?
Yes, by a wide margin at list prices. Gemini 3.8 Flash costs $0.75 per million input tokens and $3.75 per million output tokens through December 31, 2026, rising to $1.50 and $7.50 on January 1, 2027. GPT-6 Astra costs $10 and $50.
Why compare ChatGPT with a Flash model?
Google calls Gemini 3.8 Flash its best reasoning and coding model yet, so it is the closest current Gemini match for GPT-6 Astra, even though it is priced as a Flash model.
Which accepts more input types?
Gemini 3.8 Flash accepts text, images, video, audio and PDFs. OpenAI's model page lists text and image input for GPT-6 Astra.