DeepSeek R1 vs GPT-5.1 Codex
Side-by-side benchmark comparison across coding, math, reasoning, speed, and pricing.
GPT-5.1 Codex by OpenAI wins on 8 of 14 benchmarks against DeepSeek R1 by DeepSeek, 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, GPT-5.1 Codex scores 1395 on Chatbot Arena ELO compared to DeepSeek R1's 1355, while DeepSeek R1 scores 84.0% 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 DeepSeek R1's 86.0%, while GPT-5.1 Codex scores 78.0% on SWE-bench Verified compared to DeepSeek R1's 49.2%, while GPT-5.1 Codex scores 85.0% on LiveCodeBench compared to DeepSeek R1's 50.0%.
Math: In math, DeepSeek R1 scores 97.3% on MATH compared to GPT-5.1 Codex's 85.0%, while DeepSeek R1 scores 97.0% on GSM8K compared to GPT-5.1 Codex's 95.0%.
Reasoning: In reasoning, DeepSeek R1 scores 71.5% on GPQA Diamond compared to GPT-5.1 Codex's 65.0%, while GPT-5.1 Codex scores 52.0% on ARC-AGI compared to DeepSeek R1's 14.0%.
Context: In context, GPT-5.1 Codex scores 400K on Context Length compared to DeepSeek R1's 64K.
Pricing Comparison
DeepSeek R1 costs $0.70/1M input tokens and $2.5/1M output tokens, while GPT-5.1 Codex costs $1.3/1M input and $10.0/1M output. DeepSeek R1 is the more affordable option for API usage.
Speed Comparison
DeepSeek R1 generates output at 35 tok/s compared to GPT-5.1 Codex's 85 tok/s, and the time to first token is 950 ms for DeepSeek R1 versus 400 ms for GPT-5.1 Codex. GPT-5.1 Codex delivers faster throughput.
Verdict
For developers prioritizing math and affordability, DeepSeek R1 has the edge. For those who value coding and general intelligence and speed, GPT-5.1 Codex is the stronger choice.
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DeepSeek R1 vs GPT-5.1 Codex — FAQ
Which is better, DeepSeek R1 or GPT-5.1 Codex?
GPT-5.1 Codex wins on more benchmarks overall (8 vs 6). However, the best choice depends on your specific needs — each model excels in different areas.
How does DeepSeek R1 compare to GPT-5.1 Codex for coding?
GPT-5.1 Codex is better for coding, scoring 78.0% on SWE-bench Verified compared to 49.2%. SWE-bench tests real-world software engineering by resolving actual GitHub issues.
Is DeepSeek R1 cheaper than GPT-5.1 Codex?
Yes, DeepSeek R1 is cheaper. DeepSeek R1 costs $0.70/1M input and $2.5/1M output tokens. GPT-5.1 Codex costs $1.3/1M input and $10.0/1M output tokens.
Which is faster, DeepSeek R1 or GPT-5.1 Codex?
GPT-5.1 Codex is faster, generating output at 85 tok/s compared to 35 tok/s. Faster output speed means shorter wait times for API responses.
What benchmarks does the DeepSeek R1 vs GPT-5.1 Codex comparison cover?
This comparison covers 14 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.