GoogleGemini 3.1 Flash-LiteVSOpenAIGPT-5.5

Analysis by:the whichllmmodel Editorial Team|Updated: June 2026

Our Take

We recommend GPT-5.5 if you need peak intelligence for complex complex codebases, multi-file repositories, and architectural planning, or the 20.0x cheaper Gemini 3.1 Flash-Lite if your workflow is limited to scripting single-file apps or clearly defined functions. While GPT-5.5 holds a major reasoning advantage, Gemini 3.1 Flash-Lite is optimized for high-volume budget pipelines. Choose GPT-5.5 for architectural codebase planning, or Gemini 3.1 Flash-Lite to maximize your budget for basic scripts.

▶WHY?

Benchmark Calculations & Evidence:

Coding Evaluation: Gemini 3.1 Flash-Lite was evaluated on LiveCodeBench (scoring 72%), while GPT-5.5 was evaluated on SWE-bench Pro (scoring 58.6%).

Reasoning Accuracy: Both models were evaluated on the GPQA Diamond benchmark. GPT-5.5 scored 93.6%, while Gemini 3.1 Flash-Lite scored 82.2%.

Cost Efficiency: Gemini 3.1 Flash-Lite pricing ($0.25/M input, $1.5/M output) is 20.0x cheaper than GPT-5.5 ($5/M input, $30/M output).

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Model Specs

Gemini 3.1 Flash-Lite

Website

Benchmarks & Scores

Coding (live-code-bench)

72%

scripting single-file apps or clearly defined functions

Reasoning (gpqa-diamond)

82.2%

graduate-level science QA

Cost & Context

Cost (per 1M tokens)20.0x cheaper

$0.56Input: $0.25 | Output: $1.50

Context Window

1.05M tokens

Model Specs

GPT-5.5

Website

Benchmarks & Scores

Coding (swe-bench-pro)

58.6%

complex codebases, multi-file repositories, and architectural planning

Reasoning (gpqa-diamond)Winner (+11.4%)

93.6%

graduate-level science QA

Cost & Context

Cost (per 1M tokens)

$11.25Input: $5.00 | Output: $30.00

Context WindowLarger

1.05M tokens

Read our data collection methodology

Frequently Asked Questions about Gemini 3.1 Flash-Lite vs GPT-5.5

Gemini 3.1 Flash-Lite is cheaper than GPT-5.5. Gemini 3.1 Flash-Lite has a blended cost of $0.56/1M tokens, which is about 20.0x cheaper than GPT-5.5 at $11.25/1M tokens.

For coding tasks, Gemini 3.1 Flash-Lite scores 72% on live-code-bench (scripting single-file apps or clearly defined functions), while GPT-5.5 scores 58.6% on swe-bench-pro (complex codebases, multi-file repositories, and architectural planning).

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