Claude Opus 4 vs GPT-5.1 Codex Mini
Side-by-side benchmark comparison across coding, math, reasoning, speed, and pricing.
Claude Opus 4 by Anthropic wins on 10 of 17 benchmarks against GPT-5.1 Codex Mini by OpenAI, which leads on 7. 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, Claude Opus 4 scores 1375 on Chatbot Arena ELO compared to GPT-5.1 Codex Mini's 1310, while Claude Opus 4 scores 83.0% on MMLU-Pro compared to GPT-5.1 Codex Mini's 72.0%.
Coding: In coding, Claude Opus 4 scores 90.0% on HumanEval+ compared to GPT-5.1 Codex Mini's 88.0%, while Claude Opus 4 scores 72.5% on SWE-bench Verified compared to GPT-5.1 Codex Mini's 55.0%, while GPT-5.1 Codex Mini scores 65.0% on LiveCodeBench compared to Claude Opus 4's 60.0%, while Claude Opus 4 scores 1171 on Design Arena ELO compared to GPT-5.1 Codex Mini's 1087, while Claude Opus 4 scores 1177 on Website Arena ELO compared to GPT-5.1 Codex Mini's 1123.
Math: In math, Claude Opus 4 scores 86.0% on MATH compared to GPT-5.1 Codex Mini's 78.0%, while Claude Opus 4 scores 95.0% on GSM8K compared to GPT-5.1 Codex Mini's 92.0%.
Reasoning: In reasoning, Claude Opus 4 scores 79.6% on GPQA Diamond compared to GPT-5.1 Codex Mini's 52.0%, while Claude Opus 4 scores 45.0% on ARC-AGI compared to GPT-5.1 Codex Mini's 35.0%.
Context: In context, GPT-5.1 Codex Mini scores 400K on Context Length compared to Claude Opus 4's 200K.
Pricing Comparison
Claude Opus 4 costs $15.0/1M input tokens and $75.0/1M output tokens, while GPT-5.1 Codex Mini costs $0.25/1M input and $2.0/1M output. GPT-5.1 Codex Mini is the more affordable option for API usage.
Speed Comparison
Claude Opus 4 generates output at 50 tok/s compared to GPT-5.1 Codex Mini's 170 tok/s, and the time to first token is 550 ms for Claude Opus 4 versus 180 ms for GPT-5.1 Codex Mini. GPT-5.1 Codex Mini delivers faster throughput.
Verdict
For developers prioritizing coding and general intelligence and math, Claude Opus 4 has the edge. For those who value affordability and speed, GPT-5.1 Codex Mini is the stronger choice.
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Claude Opus 4 vs GPT-5.1 Codex Mini — FAQ
Which is better, Claude Opus 4 or GPT-5.1 Codex Mini?
Claude Opus 4 wins on more benchmarks overall (10 vs 7). However, the best choice depends on your specific needs — each model excels in different areas.
How does Claude Opus 4 compare to GPT-5.1 Codex Mini for coding?
Claude Opus 4 is better for coding, scoring 72.5% on SWE-bench Verified compared to 55.0%. SWE-bench tests real-world software engineering by resolving actual GitHub issues.
Is Claude Opus 4 cheaper than GPT-5.1 Codex Mini?
Yes, GPT-5.1 Codex Mini is cheaper. Claude Opus 4 costs $15.0/1M input and $75.0/1M output tokens. GPT-5.1 Codex Mini costs $0.25/1M input and $2.0/1M output tokens.
Which is faster, Claude Opus 4 or GPT-5.1 Codex Mini?
GPT-5.1 Codex Mini is faster, generating output at 170 tok/s compared to 50 tok/s. Faster output speed means shorter wait times for API responses.
What benchmarks does the Claude Opus 4 vs GPT-5.1 Codex Mini comparison cover?
This comparison covers 17 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.