GPT-5.1 vs GPT-5.6 Terra

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

GPT-5.1 by OpenAI wins on 4 of 7 benchmarks against GPT-5.6 Terra by OpenAI, which leads on 3. This head-to-head comparison covers coding, math, reasoning, speed, and pricing metrics from our benchmark data.

Category-by-Category Breakdown

Coding: In coding, GPT-5.6 Terra scores 76.7 on AA Coding Index compared to GPT-5.1's 49.4.

Reasoning: In reasoning, GPT-5.6 Terra scores 89.0% on GPQA Diamond compared to GPT-5.1's 86.2%, while GPT-5.1 scores 75.7% on τ²-Bench Airline compared to GPT-5.6 Terra's 73.3%.

Context: In context, GPT-5.6 Terra scores 1.1M on Context Length compared to GPT-5.1's 400K.

Pricing Comparison

GPT-5.1 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 is the more affordable option for API usage.

Verdict

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

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GPT-5.1 vs GPT-5.6 Terra — FAQ

Which is better, GPT-5.1 or GPT-5.6 Terra?

GPT-5.1 wins on more benchmarks overall (4 vs 3). However, the best choice depends on your specific needs — each model excels in different areas.

How does GPT-5.1 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 cheaper than GPT-5.6 Terra?

Yes, GPT-5.1 is cheaper. GPT-5.1 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 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 vs GPT-5.6 Terra comparison cover?

This comparison covers 7 benchmarks including GPQA Diamond, Input Cost, Output Cost, Context Length, AA Coding Index, Cached Input Cost, τ²-Bench Airline. Metrics span general intelligence, coding, math, reasoning, speed, and cost categories.