Which is cheaper, Gemini 3.8 Flash and GPT-6 Astra?

Gemini 3.8 Flash has the lowest input price. Per 1M input tokens: Gemini 3.8 Flash from $0.75 and GPT-6 Astra from $10.00.

Which has the larger context window, Gemini 3.8 Flash and GPT-6 Astra?

GPT-6 Astra has the largest context window: Gemini 3.8 Flash 1,048,576 tokens and GPT-6 Astra 1,050,000 tokens.

Which is better for coding, Gemini 3.8 Flash and GPT-6 Astra?

GPT-6 Astra scores highest on the Artificial Analysis Coding Index: Gemini 3.8 Flash 76.3 and GPT-6 Astra 77.1.

Can I switch between Gemini 3.8 Flash and GPT-6 Astra without changing my code?

Yes. All of them are served through FastRouter's OpenAI-compatible API, so switching is a change of the model parameter (google/gemini-3.8-flash, openai/gpt-6-astra).

Gemini 3.8 Flash vs GPT-6 Astra

Side-by-side pricing per provider, context window, benchmark scores and speed, all on one OpenAI-compatible API.

Gemini 3.8 Flash Googlegoogle/gemini-3.8-flash

GPT-6 Astra OpenAIopenai/gpt-6-astra

Creator

Google

OpenAI

Released

Sep 2, 2026

Sep 4, 2026

Context window

1.05M

Max output

66K

128K

Input / 1MLowest provider price

$0.75

$10.00

Output / 1MLowest provider price

$3.75

$50.00

Providers

IntelligenceArtificial Analysis index

40.9

50.9

CodingArtificial Analysis index

76.3

77.1

Accepts

Text, Image, Audio, Video, Files

Text, Image

Produces

Text

Tool calling

Yes

Structured output

Yes

Reasoning

Yes

Gemini 3.8 Flash vs GPT-6 Astra: summary

Gemini 3.8 Flash and GPT-6 Astra are both available through FastRouter's OpenAI-compatible API, so switching between them is a change of model id, not a new integration.

Gemini 3.8 Flash, from Google, has a 1,048,576-token context window, costs from $0.75/1M input and $3.75/1M output tokens across 2 providers and scores 40.9 on the Artificial Analysis Intelligence Index.

GPT-6 Astra, from OpenAI, has a 1,050,000-token context window, costs $10.00/1M input and $50.00/1M output tokens and scores 50.9 on the Artificial Analysis Intelligence Index.

Gemini 3.8 Flash is the cheapest on input, 13× cheaper than the next model, GPT-6 Astra has the largest context window, GPT-6 Astra scores highest for intelligence and GPT-6 Astra leads on coding.

Switch with one line

client = OpenAI(base_url="https://api.fastrouter.ai/api/v1", api_key="<FASTROUTER_API_KEY>") client.chat.completions.create(model="google/gemini-3.8-flash", messages=[...]) # or client.chat.completions.create(model="openai/gpt-6-astra", messages=[...])

Full API docs

Frequently asked questions

More comparisons

Benchmark scores sourced from ArtificialAnalysis