GPT-5.1 Codex Mini vs o1
Side-by-side benchmark comparison across coding, math, reasoning, speed, and pricing.
GPT-5.1 Codex Mini by OpenAI wins on 9 of 15 benchmarks against o1 by OpenAI, which leads on 6. This head-to-head comparison covers coding, math, reasoning, speed, and pricing metrics from our benchmark data.
Category-by-Category Breakdown
General Intelligence: In general intelligence, o1 scores 1360 on Chatbot Arena ELO compared to GPT-5.1 Codex Mini's 1310, while o1 scores 82.0% on MMLU-Pro compared to GPT-5.1 Codex Mini's 72.0%.
Coding: In coding, o1 scores 89.0% on HumanEval+ compared to GPT-5.1 Codex Mini's 88.0%, while GPT-5.1 Codex Mini scores 55.0% on SWE-bench Verified compared to o1's 48.9%, while GPT-5.1 Codex Mini scores 65.0% on LiveCodeBench compared to o1's 55.0%.
Math: In math, o1 scores 94.8% on MATH compared to GPT-5.1 Codex Mini's 78.0%, while o1 scores 97.5% on GSM8K compared to GPT-5.1 Codex Mini's 92.0%.
Reasoning: In reasoning, o1 scores 77.3% on GPQA Diamond compared to GPT-5.1 Codex Mini's 52.0%, while GPT-5.1 Codex Mini scores 35.0% on ARC-AGI compared to o1's 32.0%.
Context: In context, GPT-5.1 Codex Mini scores 400K on Context Length compared to o1's 200K.
Pricing Comparison
GPT-5.1 Codex Mini costs $0.25/1M input tokens and $2.0/1M output tokens, while o1 costs $15.0/1M input and $60.0/1M output. GPT-5.1 Codex Mini is the more affordable option for API usage.
Speed Comparison
GPT-5.1 Codex Mini generates output at 170 tok/s compared to o1's 35 tok/s, and the time to first token is 180 ms for GPT-5.1 Codex Mini versus 1000 ms for o1. GPT-5.1 Codex Mini delivers faster throughput.
Verdict
For developers prioritizing coding and affordability and speed, GPT-5.1 Codex Mini has the edge. For those who value general intelligence and math, o1 is the stronger choice.
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GPT-5.1 Codex Mini vs o1 — FAQ
Which is better, GPT-5.1 Codex Mini or o1?
GPT-5.1 Codex Mini wins on more benchmarks overall (9 vs 6). However, the best choice depends on your specific needs — each model excels in different areas.
How does GPT-5.1 Codex Mini compare to o1 for coding?
GPT-5.1 Codex Mini is better for coding, scoring 55.0% on SWE-bench Verified compared to 48.9%. SWE-bench tests real-world software engineering by resolving actual GitHub issues.
Is GPT-5.1 Codex Mini cheaper than o1?
Yes, GPT-5.1 Codex Mini is cheaper. GPT-5.1 Codex Mini costs $0.25/1M input and $2.0/1M output tokens. o1 costs $15.0/1M input and $60.0/1M output tokens.
Which is faster, GPT-5.1 Codex Mini or o1?
GPT-5.1 Codex Mini is faster, generating output at 170 tok/s compared to 35 tok/s. Faster output speed means shorter wait times for API responses.
What benchmarks does the GPT-5.1 Codex Mini vs o1 comparison cover?
This comparison covers 15 benchmarks including Chatbot Arena ELO, MMLU-Pro, HumanEval+, MATH, GPQA Diamond, SWE-bench Verified, Output Speed, LiveCodeBench, and more. Metrics span general intelligence, coding, math, reasoning, speed, and cost categories.