GPT-5.1 Codex vs GPT-5.2
Side-by-side benchmark comparison across coding, math, reasoning, speed, and pricing.
GPT-5.2 by OpenAI wins on 9 of 14 benchmarks against GPT-5.1 Codex by OpenAI, which leads on 4. This head-to-head comparison covers coding, math, reasoning, speed, and pricing metrics from the AI Value Index.
Category-by-Category Breakdown
General Intelligence: In general intelligence, GPT-5.2 scores 1475 on Chatbot Arena ELO compared to GPT-5.1 Codex's 1395, while GPT-5.2 scores 83.0% on MMLU-Pro compared to GPT-5.1 Codex's 82.0%.
Coding: In coding, GPT-5.1 Codex scores 96.0% on HumanEval+ compared to GPT-5.2's 95.0%, while GPT-5.2 scores 80.0% on SWE-bench Verified compared to GPT-5.1 Codex's 78.0%, while GPT-5.1 Codex scores 85.0% on LiveCodeBench compared to GPT-5.2's 80.0%.
Math: In math, GPT-5.2 scores 97.0% on MATH compared to GPT-5.1 Codex's 85.0%, while GPT-5.2 scores 99.0% on GSM8K compared to GPT-5.1 Codex's 95.0%.
Reasoning: In reasoning, GPT-5.2 scores 92.4% on GPQA Diamond compared to GPT-5.1 Codex's 65.0%, while GPT-5.2 scores 54.2% on ARC-AGI compared to GPT-5.1 Codex's 52.0%.
Context: In context, both score 400K on Context Length.
Pricing Comparison
GPT-5.1 Codex costs $1.3/1M input tokens and $10.0/1M output tokens, while GPT-5.2 costs $1.8/1M input and $14.0/1M output. GPT-5.1 Codex is the more affordable option for API usage.
Speed Comparison
GPT-5.1 Codex generates output at 85 tok/s compared to GPT-5.2's 90 tok/s, and the time to first token is 400 ms for GPT-5.1 Codex versus 380 ms for GPT-5.2. GPT-5.2 delivers faster throughput.
Verdict
For developers prioritizing affordability, GPT-5.1 Codex has the edge. For those who value coding and general intelligence and math and speed, GPT-5.2 is the stronger choice.
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GPT-5.1 Codex vs GPT-5.2 — FAQ
Which is better, GPT-5.1 Codex or GPT-5.2?
GPT-5.2 wins on more benchmarks overall (9 vs 4). However, the best choice depends on your specific needs — each model excels in different areas.
How does GPT-5.1 Codex compare to GPT-5.2 for coding?
GPT-5.2 is better for coding, scoring 80.0% on SWE-bench Verified compared to 78.0%. SWE-bench tests real-world software engineering by resolving actual GitHub issues.
Is GPT-5.1 Codex cheaper than GPT-5.2?
Yes, GPT-5.1 Codex is cheaper. GPT-5.1 Codex costs $1.3/1M input and $10.0/1M output tokens. GPT-5.2 costs $1.8/1M input and $14.0/1M output tokens.
Which is faster, GPT-5.1 Codex or GPT-5.2?
GPT-5.2 is faster, generating output at 90 tok/s compared to 85 tok/s. Faster output speed means shorter wait times for API responses.
What benchmarks does the GPT-5.1 Codex vs GPT-5.2 comparison cover?
This comparison covers 14 benchmarks including Chatbot Arena ELO, MMLU-Pro, HumanEval+, MATH, SWE-bench Verified, GPQA Diamond, Output Speed, Time to First Token, and more. Metrics span general intelligence, coding, math, reasoning, speed, and cost categories.