Model comparison
Compare GPT-6 Astra and Gemini 3.8 Flash using the same provider-sourced text & reasoning rubric. No mystery score and no invented benchmark ranking.
Facts checked September 4, 2026
Set your usage. Your estimate updates as you type.
Example: 6,000 input tokens for 10 pages, plus a 500-token summary. Page lengths vary; adjust the numbers below.
One run sends your input to the model once and receives an answer. Tokens are pieces of text: input is what you send, output is the answer you receive.
Estimates exclude taxes, tools, cache storage/writes, free allowances and custom discounts. Image estimates cover output only, not prompt or reference-image charges. Quality modes differ by model. Unlisted settings are not treated as free.
| Model | Access | Estimated total (USD) |
|---|---|---|
| Gemini 3.8 FlashGoogle | $0.0064 | |
| GPT-6 AstraOpenAI | OpenAI | $0.085 |
Quick take
OpenAI's most capable model for difficult end-to-end work, combining frontier reasoning with a million-token context window and a broad set of agent tools.
Access is still rolling out, fine-tuning is not supported, and requests above 272K input tokens use higher rates across the full request. Confirm access and measure total task cost before standardizing on Astra.
Google's stable, high-efficiency multimodal model for agents, software work, and large mixed-media inputs at an introductory Flash-tier price.
Free and paid Gemini services have materially different data-use terms. Verify billing status and regional availability for the exact project.
Compare the published facts
Values use each provider's own published units and limits. A blank means the provider did not publish a directly comparable value in the sources reviewed.
| Text & reasoning | GPT-6 Astra | Gemini 3.8 Flash |
|---|---|---|
| Context windowMaximum combined prompt and working context documented by the provider. | 1.05M tokens | 1,048,576 tokens |
| Maximum outputProvider-published response limit, where available. | 128K tokens | 65,536 tokens |
| Knowledge cutoffLatest reliable knowledge date explicitly published by the model provider. Search and connected tools can retrieve newer information but do not change the model's built-in cutoff. | April 30, 2026 | March 2026; some domains may lag to January 2025 |
| Input priceCurrent standard list price per million input tokens unless noted. | $10 / 1M | $0.75 / 1M promo |
| Output priceCurrent standard list price per million output tokens unless noted. | $50 / 1M | $3.75 / 1M promo |
| InputsMedia types accepted by the listed model endpoint. | Text, image | Text, image, video, audio, PDF |
| Tools & agentsSelected native tools and agent-building capabilities, not an exhaustive list. | Functions, search, code, computer, image, MCP | Functions, search, code execution, file search |
How to choose
Start with the job you need to complete, then validate cost, access, and policy details on your exact provider route.
OpenAI says API content is not used for model training by default. Standard abuse-monitoring logs may be retained for up to 30 days, with additional controls available to qualifying organizations.
Provider and API links
Google says paid Gemini API prompts and responses are not used to improve its products. Unpaid-service content generally may be used, with different treatment for EEA, UK, and Swiss users; check the current terms for your account and region.
Provider and API links
Frequently asked questions
GPT-6 Astra: OpenAI's most capable model for difficult end-to-end work, combining frontier reasoning with a million-token context window and a broad set of agent tools. Gemini 3.8 Flash: Google's stable, high-efficiency multimodal model for agents, software work, and large mixed-media inputs at an introductory Flash-tier price.
Consider GPT-6 Astra when your priority is Complex, long-running agent workflows. Consider Gemini 3.8 Flash when your priority is High-volume multimodal agents. Test both with your own data and provider route before committing.
No. This comparison aligns provider-published facts for the Text & reasoning category. It does not claim a universal winner or combine incompatible third-party benchmark scores.
