head-to-head

OpenAI: GPT-5.6 Luna Pro vs Google: Gemini 3.5 Flash

Side-by-side comparison of specs, pricing, benchmark scores, and task rankings. Updated 2026-09-23.

OpenAI: GPT-5.6 Luna Pro Google: Gemini 3.5 Flash
Vendoropenaigoogle
Quality Score100100
Benchmark Score-53.5
Input Price$0.20/M$1.50/M
Output Price$1.20/M$9.00/M
Context Window1,050,0001,048,576
Max Output128,00065,536
Tool Calling
Structured Output
Reasoning Mode
Vision
Audio-
Benchmark Scores
ai_index-53.8

Who wins by task?

TaskOpenAI: GPT-5.6 Luna ProGoogle: Gemini 3.5 Flash
SQL Generation 133 139
Code Review 132 142
Code Completion 131 119
Code Refactoring 136 144
Bug Fixing 136 146
Unit Test Generation 124 130
Code Documentation 131 134
Regex Writing 119 123
CI/CD Pipelines 120 126
Frontend Component Design 122 128
Data Analysis 124 132
CSV / Spreadsheet Cleanup 133 135
ETL Scripting 128 135
JSON Extraction 131 121
Bulk Data Labeling 129 118
OCR / Document Parsing 131 133
Table Extraction from PDFs 131 133
Long-Document Summarization 137 145
Short-Form Summarization 123 116
Blog Post Writing 121 127

Scores reflect capability match + benchmark data + pricing for each task. Methodology →

Related comparisons

Anthropic: Claude Opus 5 (batch) vs OpenAI: GPT-5.6 Luna Pro Anthropic: Claude Sonnet 5 vs Google: Gemini 3.5 Flash ByteDance Seed: Seed-2.0-Code vs Google: Gemini 3.5 Flash ByteDance Seed: Seed-2.0-Code vs OpenAI: GPT-5.6 Luna Pro ByteDance Seed: Seed 2.1 Turbo vs OpenAI: GPT-5.6 Luna Pro DeepSeek: DeepSeek V4.1 Flash vs OpenAI: GPT-5.6 Luna Pro DeepSeek: DeepSeek V4 Flash Vision Exp vs OpenAI: GPT-5.6 Luna Pro Google: Gemini 3.5 Flash Lite (batch) vs OpenAI: GPT-5.6 Luna Pro

The Model Movers Report

One email every Friday, built from this site's own rankings: the current top five by benchmark score, every model released in the last seven days, and one note worked out from that week's numbers. You can unsubscribe from any issue with one click.