GPT-6 Astra vs GPT-6 Sol: a data-driven comparison

Side-by-side comparison

Criterion	GPT-6 Astra	GPT-6 Sol
Developer	OpenAI	OpenAI
Released	September 4, 2026	September 22, 2026
Capability index	94.7 / 100	89.2 / 100
Input price	$10	$2
Output price	$50	$10
Cost of a typical task	$0.30	$0.06
Context window	1,050,000 tokens	1,050,000 tokens
Maximum output	128,000 tokens	128,000 tokens
Reasoning mode	Yes	Yes
Tool calling	Yes	Yes
Accepted inputs	text, image, PDF	text, image, PDF
Open weights	No	No
Knowledge cutoff	April 30, 2026	April 20, 2026

The match-up at a glance

This comparison pits two frontier models, the ones you pick when quality comes first against each other: GPT-6 Astra and GPT-6 Sol, both built by OpenAI. The first dates from September 4, 2026, the second from September 22, 2026.

All figures below come from public sources checked on October 22, 2026: models.dev and OpenRouter for prices and capabilities, Epoch AI for scores.

Which one is more capable?

On our capability index, GPT-6 Astra scores 94.7 out of 100 and GPT-6 Sol 89.2. GPT-6 Astra leads by 5.5 points.

On the 5 benchmarks reported for both, GPT-6 Astra wins 4 times and GPT-6 Sol 0:

GPQA Diamond (PhD-level science questions): GPT-6 Astra 95.8%, GPT-6 Sol 94.3%
OTIS Mock AIME (competition mathematics problems): GPT-6 Astra 100%, GPT-6 Sol 100%
FrontierMath (very hard research-level mathematics): GPT-6 Astra 93.7%, GPT-6 Sol 89.8%
FrontierCode (advanced programming tasks): GPT-6 Astra 53.3%, GPT-6 Sol 49.3%
APEX-Agents (professional tasks carried out by an agent): GPT-6 Astra 64.7%, GPT-6 Sol 54.3%

Budget

GPT-6 Astra costs $10 per million input tokens and $50 per million output tokens; GPT-6 Sol costs $2 and $10.

For a typical agent task (read 20,000 tokens, write 2,000), expect $0.30 with GPT-6 Astra versus $0.06 with GPT-6 Sol. GPT-6 Sol is 5 times cheaper, a gap that adds up quickly over 1,000 tasks: $240 difference.

Run the numbers with your own volumes in the agent cost calculator.

Context and capabilities

Both models have the same context window: 1,050,000 tokens, roughly 1,575 pages.

Reasoning mode: GPT-6 Astra yes, GPT-6 Sol yes. Tool calling: GPT-6 Astra yes, GPT-6 Sol yes. Image input: GPT-6 Astra yes, GPT-6 Sol yes.

Neither publishes its weights: both are used through an API.

Knowledge cutoff: April 30, 2026 for GPT-6 Astra, April 20, 2026 for GPT-6 Sol.

In short

Our reading of the data:

Choose GPT-6 Astra for a higher capability index.
Choose GPT-6 Sol for a lower cost.

This verdict relies on public figures; it does not replace a trial on your own tasks.

Frequently asked questions

GPT-6 Astra or GPT-6 Sol: which is better?

On our index (Epoch AI data), GPT-6 Astra scores 94.7 and GPT-6 Sol 89.2 out of 100. The best choice also depends on price and on your use case.

Which one is cheaper?

GPT-6 Sol. To read 20,000 tokens and write 2,000, expect $0.30 with GPT-6 Astra and $0.06 with GPT-6 Sol (prices as of October 22, 2026).

Which one has the larger context window?

Neither: both accept 1,050,000 tokens.

Can I run GPT-6 Astra or GPT-6 Sol on my own servers?

No: both are closed models, available through an API.

GPT-6 Astra vs GPT-6 Sol