What is the best alternative to GPT-6 Astra?

Gemini 4 Carbon is the closest model that scores higher on the BenchLeader Index (68.9 against 68.2). For less money, Claude Opus 5.5 scores 69.2 at $8.00 per 1M tokens.

Is there a cheaper alternative to GPT-6 Astra?

Yes: Claude Opus 5.5 (69.2, $8.00), Gemini 4 Carbon (68.9, $8.00) and GPT-6.1 Sol (67.2, $4.00), each within 4 Index points and cheaper than GPT-6 Astra's $20.00.

Is there an open-source alternative to GPT-6 Astra?

The best open-weights models on the BenchLeader Index are Kimi K3 (62.1), GLM-5 (60.2) and GLM 5.2 (60.1). You can download and run them yourself; check each licence on its model page.

How are these alternatives chosen?

From the models ranked on the BenchLeader Index today: the ones just above GPT-6 Astra, cheaper ones within 4 points, ones at least 1.5× as fast within 4 points, and the best open-weights models. Prices are list prices blended three input tokens to one output.

OpenAI

GPT-6 Astra alternatives

Data as of 2 Nov 2026 · ranked on the BenchLeader Index

As of 2 Nov 2026, GPT-6 Astra by OpenAI scores 68.2 on the BenchLeader Index at $20.00 per 1M tokens blended. Gemini 4 Carbon scores higher (68.9); Claude Opus 5.5 is the best cheaper model within 4 points (69.2 at $8.00); Claude Opus 5.5 is at least 1.5× as fast at a similar score; Kimi K3 is the best open-weights option (62.1).

Scores higher

The closest models above GPT-6 Astra on the Index.

Gemini 4 Carbon Google compare68.9 · $8.00
Claude Opus 5.5 Anthropic compare69.2 · $8.00

Cheaper, nearly as good

Within 4 Index points, for less per token.

Claude Opus 5.5 Anthropic compare69.2 · $8.00
Gemini 4 Carbon Google compare68.9 · $8.00
GPT-6.1 Sol OpenAI compare67.2 · $4.00
Gemini 4 Argon Google compare65.9 · $4.00
Claude Opus 5 Anthropic compare65.4 · $10.00

Faster

At least 1.5× the output speed, within 4 points.

Claude Opus 5.5 Anthropic compare69.2 · $8.00
Gemini 4 Carbon Google compare68.9 · $8.00
GPT-6.1 Sol OpenAI compare67.2 · $4.00

Open weights

The best models whose weights you can run yourself.

Kimi K3 Moonshot AI compare62.1 · $6.00
GLM-5 Zhipu AI compare60.2 · $1.55
GLM 5.2 Zhipu AI compare60.1 · $2.15

Every alternative side by side

Model	Index	$ / 1M blended	Tokens / s	Why
GPT-6 Astra (this model)	68.2	$20.00	44	–
Claude Opus 5.5	69.2	$8.00	96	scores higher, cheaper, faster
Gemini 4 Carbon	68.9	$8.00	95	scores higher, cheaper, faster
GPT-6.1 Sol	67.2	$4.00	87	cheaper, faster
Gemini 4 Argon	65.9	$4.00	83	cheaper
Claude Opus 5	65.4	$10.00	53	cheaper
Kimi K3	62.1	$6.00	66	open weights
GLM-5	60.2	$1.55	62	open weights
GLM 5.2	60.1	$2.15	89	open weights

Prices are list prices blended three input tokens to one output; speeds are measured medians, credited on each model page. The Index is BenchLeader's own, from independent benchmarks.

Questions people ask

What is the best alternative to GPT-6 Astra?: Gemini 4 Carbon is the closest model that scores higher on the BenchLeader Index (68.9 against 68.2). For less money, Claude Opus 5.5 scores 69.2 at $8.00 per 1M tokens.
Is there a cheaper alternative to GPT-6 Astra?: Yes: Claude Opus 5.5 (69.2, $8.00), Gemini 4 Carbon (68.9, $8.00) and GPT-6.1 Sol (67.2, $4.00), each within 4 Index points and cheaper than GPT-6 Astra's $20.00.
Is there an open-source alternative to GPT-6 Astra?: The best open-weights models on the BenchLeader Index are Kimi K3 (62.1), GLM-5 (60.2) and GLM 5.2 (60.1). You can download and run them yourself; check each licence on its model page.
How are these alternatives chosen?: From the models ranked on the BenchLeader Index today: the ones just above GPT-6 Astra, cheaper ones within 4 points, ones at least 1.5× as fast within 4 points, and the best open-weights models. Prices are list prices blended three input tokens to one output.