head-to-head

Google: Gemini 3.1 Pro Preview Custom Tools vs OpenAI: GPT-5.3-Codex

Side-by-side comparison of specs, pricing, benchmark scores, and task rankings. Updated 2026-04-29.

	Google: Gemini 3.1 Pro Preview Custom Tools	OpenAI: GPT-5.3-Codex
Vendor	google	openai
Quality Score	100	100
Input Price	$2.00/M	$1.75/M
Output Price	$12.00/M	$14.00/M
Context Window	1,048,576	400,000
Max Output	65,536	128,000
Tool Calling	✓	✓
Structured Output	✓	✓
Reasoning Mode	✓	✓
Vision	✓	✓
Audio	✓	-

Who wins by task?

Task	Google: Gemini 3.1 Pro Preview Custom Tools	OpenAI: GPT-5.3-Codex
SQL Generation	132	132
Code Completion	117	116
Code Documentation	129	128
Regex Writing	117	116
CSV / Spreadsheet Cleanup	132	132
JSON Extraction	121	120
Bulk Data Labeling	117	117
Long-Document Summarization	136	136
Short-Form Summarization	113	112
Blog Post Writing	120	120

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