GPT-5.1 Codex vs GPT-5.6 Terra
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-5.6 Terra 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-5.6 Terra scores 89.0% on GPQA Diamond compared to GPT-5.1 Codex's 65.0%.
Context: In context, GPT-5.6 Terra 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-5.6 Terra costs $2.0/1M input and $12.0/1M 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-5.6 Terra — FAQ
Which is better, GPT-5.1 Codex or GPT-5.6 Terra?
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-5.6 Terra 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-5.6 Terra?
Yes, GPT-5.1 Codex is cheaper. GPT-5.1 Codex costs $1.3/1M input and $10.0/1M output tokens. GPT-5.6 Terra costs $2.0/1M input and $12.0/1M output tokens.
Which is faster, GPT-5.1 Codex or GPT-5.6 Terra?
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-5.6 Terra 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.