Gemini 3.5 Flash vs GPT-5.1
Side-by-side benchmark comparison across coding, math, reasoning, speed, and pricing.
Gemini 3.5 Flash by Google wins on 6 of 9 benchmarks against GPT-5.1 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, Gemini 3.5 Flash scores 70.1 on AA Coding Index compared to GPT-5.1's 49.4, while Gemini 3.5 Flash scores 1275 on Design Arena ELO compared to GPT-5.1's 1158, while Gemini 3.5 Flash scores 1275 on Website Arena ELO compared to GPT-5.1's 1179.
Reasoning: In reasoning, Gemini 3.5 Flash scores 92.8% on GPQA Diamond compared to GPT-5.1's 86.2%, while GPT-5.1 scores 75.7% on τ²-Bench Airline compared to Gemini 3.5 Flash's 74.7%.
Context: In context, Gemini 3.5 Flash scores 1.0M on Context Length compared to GPT-5.1's 400K.
Pricing Comparison
Gemini 3.5 Flash costs $1.5/1M input tokens and $9.0/1M output tokens, while GPT-5.1 costs $1.3/1M input and $10.0/1M 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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Gemini 3.5 Flash vs GPT-5.1 — FAQ
Which is better, Gemini 3.5 Flash or GPT-5.1?
Gemini 3.5 Flash wins on more benchmarks overall (6 vs 3). However, the best choice depends on your specific needs — each model excels in different areas.
How does Gemini 3.5 Flash compare to GPT-5.1 for coding?
SWE-bench Verified data is not available for both models. Check the detailed comparison charts above for other coding-related metrics.
Is Gemini 3.5 Flash cheaper than GPT-5.1?
Yes, GPT-5.1 is cheaper. Gemini 3.5 Flash costs $1.5/1M input and $9.0/1M output tokens. GPT-5.1 costs $1.3/1M input and $10.0/1M output tokens.
Which is faster, Gemini 3.5 Flash or GPT-5.1?
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 Gemini 3.5 Flash vs GPT-5.1 comparison cover?
This comparison covers 9 benchmarks including GPQA Diamond, Input Cost, Output Cost, Context Length, AA Coding Index, Cached Input Cost, Design Arena ELO, τ²-Bench Airline, and more. Metrics span general intelligence, coding, math, reasoning, speed, and cost categories.