Gemini 4 Argon vs GPT-6 Astra

As of October 21, 2026, GPT-6 Astra costs 400% more per input token than Gemini 4 Argon ($10.00 vs $2.00 per 1M) and has a 922K-token context window versus 1M. Gemini 4 Argon's price is introductory through November 30, 2026.

Prices from LiteLLM's price fileChecked October 21, 2026

Gemini 4 Argon vs GPT-6 Astra side by side

Headline prices in US dollars per 1M tokens: each model's own lab where it sells it, otherwise its cheapest provider. Source: LiteLLM model price file, as of October 21, 2026.
	Gemini 4 Argon	GPT-6 Astra
Input, per 1M tokens	$2.00	$10.00
Output, per 1M tokens	$10.00	$50.00
Cache read, per 1M tokens	$0.10	$1.00
Cache write, per 1M tokens	–	$12.50
Context window	1,048,576 tokens	922,000 tokens
Max output	1,048,576 tokens	128,000 tokens
Image input	Yes	Yes
Tool calling	Yes	Yes
Structured output (JSON)	Yes	Yes
Prompt caching	Yes	Yes
Reasoning	Yes	Yes
Providers on LiteLLM	3	8
Price shown is from	Google AI Studio, introductory until November 30, 2026	OpenAI
Added to LiteLLM	October 13, 2026	September 3, 2026

Cheapest provider for each

Gemini 4 Argon: Google AI Studio at $2.00 input and $10.00 output per 1M tokens (gemini/gemini-4-argon)
GPT-6 Astra: OpenAI at $10.00 input and $50.00 output per 1M tokens (gpt-6-astra)

Benchmark scores

From the Epoch AI Benchmarking Hub (CC BY 4.0), data as of October 13, 2026. Some results were run by Epoch and others collected by Epoch from each benchmark's own leaderboard, linked in the first column. Each model's best reported reasoning setting is shown in brackets. Higher is better. Only benchmarks with a score for both models are shown.
Benchmark	Gemini 4 Argon	GPT-6 Astra
Overall
Epoch Capabilities Index	166.4	168.8
Coding and agents
FrontierCode	47.5% (medium)	53.3% (max)
FrontierSWE	55.0% (high)	65.5% (max)
APEX-Agents	82.4%	64.7%
Reasoning and knowledge
GPQA Diamond	96.4% (high)	95.8% (max)
ARC-AGI-2	91.3% (high)	95.0% (max)
SimpleQA Verified	76.0% (high)	75.6% (max)
Math
FrontierMath (tiers 1-3)	86.0% (high)	93.7% (max)
FrontierMath (tier 4)	78.0% (high)	97.6% (high)
OTIS Mock AIME 2024-2025	100.0% (high)	100.0% (max)

When to pick which

Pick Gemini 4 Argon for

Costs 80% less per input token: $2.00 vs $10.00 per 1M.
Larger context window: 1,048,576 vs 922,000 tokens.

Pick GPT-6 Astra for

Available from 8 providers through LiteLLM, vs 3.

From differences in the data above only; where the data is equal, no reason is given.

Call Gemini 4 Argon or GPT-6 Astra with LiteLLM

Both use the OpenAI format through LiteLLM, so switching is a model name change. Set each provider's API key in the environment first.

Python SDK

from litellm import completion

messages = [{"role": "user", "content": "Hello!"}]

# Gemini 4 Argon
response = completion(model="gemini/gemini-4-argon", messages=messages)

# GPT-6 Astra
response = completion(model="gpt-6-astra", messages=messages)

# Gemini 4 Argon, falling back to GPT-6 Astra if the call fails
response = completion(model="gemini/gemini-4-argon", messages=messages, fallbacks=["gpt-6-astra"])

FAQ

Which is cheaper, Gemini 4 Argon or GPT-6 Astra?

Gemini 4 Argon is cheaper at 3 input tokens per output token: $4.00 per 1M tokens blended ($2.00 input, $10.00 output), versus $20.00 ($10.00 and $50.00) for GPT-6 Astra, as of October 21, 2026.

Which has the larger context window, Gemini 4 Argon or GPT-6 Astra?

Gemini 4 Argon has the larger context window: 1,048,576 tokens, versus 922,000 for GPT-6 Astra.

Can I switch from Gemini 4 Argon to GPT-6 Astra without changing my code?

Yes. Through LiteLLM both use the OpenAI format, so switching means changing the model name from "gemini/gemini-4-argon" to "gpt-6-astra", or pointing a LiteLLM gateway model alias at the other model. You can also use one as a fallback for the other.