GPT-5.1 Codex vs GPT-6 Astra

Side-by-side benchmark comparison across coding, math, reasoning, speed, and pricing.

GPT-5.1 Codex by OpenAI wins on 3 of 5 benchmarks against GPT-6 Astra by OpenAI, which leads on 2. This head-to-head comparison covers coding, math, reasoning, speed, and pricing metrics from our benchmark data.

Category-by-Category Breakdown

Reasoning: In reasoning, GPT-6 Astra scores 94.4% on GPQA Diamond compared to GPT-5.1 Codex's 65.0%.

Context: In context, GPT-6 Astra scores 1.1M on Context Length compared to GPT-5.1 Codex's 400K.

Pricing Comparison

GPT-5.1 Codex costs $1.3/1M input tokens and $10.0/1M output tokens, while GPT-6 Astra costs $10.0/1M input and $50.0/1M output. GPT-5.1 Codex is the more affordable option for API usage.

Verdict

GPT-5.1 Codex leads across the board in affordability, making it the stronger overall choice in this comparison.

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GPT-5.1 Codex vs GPT-6 Astra — FAQ

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

GPT-5.1 Codex wins on more benchmarks overall (3 vs 2). However, the best choice depends on your specific needs — each model excels in different areas.

How does GPT-5.1 Codex compare to GPT-6 Astra for coding?

SWE-bench Verified data is not available for both models. Check the detailed comparison charts above for other coding-related metrics.

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

Yes, GPT-5.1 Codex is cheaper. GPT-5.1 Codex costs $1.3/1M input and $10.0/1M output tokens. GPT-6 Astra costs $10.0/1M input and $50.0/1M output tokens.

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

Output speed data is not available for both models. Check the speed section of the comparison above for available performance data.

What benchmarks does the GPT-5.1 Codex vs GPT-6 Astra comparison cover?

This comparison covers 5 benchmarks including GPQA Diamond, Input Cost, Output Cost, Context Length, Cached Input Cost. Metrics span general intelligence, coding, math, reasoning, speed, and cost categories.