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GPT-5.1 Codex vs GPT-6 Astra

GPT-6 Astra leads the LLM Stats Score 60.3 to 29.6. GPT-5.1 Codex is 5.8x cheaper per token.

OpenAI · OpenAI · Updated for 2026

Which is better?

GPT-6 Astra leads the overall LLM Stats Score 60.3 to 29.6, ranking #1 overall.

On price, GPT-5.1 Codex is roughly 5.8x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

GPT-6 Astra also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose GPT-5.1 Codex

  • cost matters — it's about 5.8x cheaper per token

Choose GPT-6 Astra

  • overall performance matters — it scores 60.3 and ranks #1 on LLM Stats
  • your work emphasizes reasoning and coding — it leads those capability indexes
  • you process long inputs — it offers a 1,050,000 token context window
  • you want the most recent training data — it shipped Sep 2026

At a glance

The differences that matter most.

GPT-5.1 Codex
OpenAI
GPT-6 Astra
OpenAI
Core performance indexes
LLM Stats Score
29.6
#126
60.3
#1
Reasoning
29.8
#118
58.2
#1
Coding
21.0
#91
48.5
#1
Agents
10.5
#114
46.4
#1
Cost, coverage & limits
Benchmark wins
—
—
Input price
$1.25 / M
$10.00 / M
Output price
$10.00 / M
$50.00 / M
Context window
400,000
1,050,000

Individual benchmarks

3 reported for GPT-5.1 Codex · 22 for GPT-6 Astra

No common benchmarks found

GPT-5.1 Codex and GPT-6 Astradon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

GPT-5.1 Codex costs less

For input processing, GPT-5.1 Codex ($1.25/1M tokens) is 8.0x cheaper than GPT-6 Astra ($10.00/1M tokens).

For output processing, GPT-5.1 Codex ($10.00/1M tokens) is 5.0x cheaper than GPT-6 Astra ($50.00/1M tokens).

In conclusion, GPT-6 Astra is more expensive than GPT-5.1 Codex.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Wed Sep 09 2026 • llm-stats.com
OpenAI
GPT-5.1 Codex
Input tokens$1.25
Output tokens$10.00
Best providerOpenAI
OpenAI
GPT-6 Astra
Input tokens$10.00
Output tokens$50.00
Best providerOpenAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

GPT-6 Astra accepts 1,050,000 input tokens compared to GPT-5.1 Codex's 400,000 tokens. Both models can generate responses up to 128,000 tokens.

OpenAI
GPT-5.1 Codex
Input400,000 tokens
Output128,000 tokens
OpenAI
GPT-6 Astra
Input1,050,000 tokens
Output128,000 tokens
Wed Sep 09 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both GPT-5.1 Codex and GPT-6 Astra support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

GPT-5.1 Codex

Text
Images
Audio
Video

GPT-6 Astra

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

GPT-5.1 Codex

Proprietary

Closed source

GPT-6 Astra

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-5.1 Codex was released on 2025-11-19, while GPT-6 Astra was released on 2026-09-04.

GPT-6 Astra is 10 months newer than GPT-5.1 Codex.

GPT-5.1 Codex

Nov 19, 2025

9 months ago

GPT-6 Astra

Sep 4, 2026

4 days ago

9mo newer

Knowledge Cutoff

When training data ends

GPT-5.1 Codex has a knowledge cutoff of 2024-09-30, while GPT-6 Astra has a cutoff of 2026-04-30.

GPT-6 Astra has more recent training data (up to 2026-04-30), making it potentially better informed about events through that date compared to GPT-5.1 Codex (2024-09-30).

GPT-5.1 Codex

Sep 2024

GPT-6 Astra

Apr 2026

1.6 yr newer

Provider Availability

GPT-5.1 Codex is available from OpenAI. GPT-6 Astra is available from OpenAI.

GPT-5.1 Codex

openai logo
OpenAI
Input Price:Input: $1.25/1MOutput Price:Output: $10.00/1M

GPT-6 Astra

openai logo
OpenAI
Input Price:Input: $10.00/1MOutput Price:Output: $50.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against GPT-5.1 Codex and GPT-6 Astra side-by-side, then vote on the output you prefer.

GPT-5.1 Codex
✓ Preferred
GPT-6 Astra
Open in Playground

FAQ

Common questions about GPT-5.1 Codex vs GPT-6 Astra.

Which is better, GPT-5.1 Codex or GPT-6 Astra?

GPT-6 Astra leads the LLM Stats Score 60.3 to 29.6. GPT-5.1 Codex is made by OpenAI and GPT-6 Astra is made by OpenAI. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does GPT-5.1 Codex compare to GPT-6 Astra in benchmarks?

GPT-5.1 Codex scores SWE-Bench Verified: 73.7%, SWE-Lancer: 66.3%, Terminal-Bench 2.0: 52.8%. GPT-6 Astra scores ExploitBench: 100.0%, ARC-AGI-3: 99.9%, ARC-AGI: 98.5%, FrontierMath Tier 4 (v2): 97.6%, GPQA: 96.0%.

Is GPT-5.1 Codex cheaper than GPT-6 Astra?

GPT-5.1 Codex is 8.0x cheaper for input tokens. GPT-5.1 Codex costs $1.25/M input and $10.00/M output via openai. GPT-6 Astra costs $10.00/M input and $50.00/M output via openai.

What are the context window sizes for GPT-5.1 Codex and GPT-6 Astra?

GPT-5.1 Codex supports 400K tokens and GPT-6 Astra supports 1.1M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between GPT-5.1 Codex and GPT-6 Astra?

Key differences include LLM Stats Score (29.6 vs 60.3), context window (400K vs 1.1M), input pricing ($1.25 vs $10.00/M). See the full comparison above for benchmark-by-benchmark results.

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