Gemini 3.1 Pro preview vs GPT 5.3 Chat latest

Name: GPT 5.3 Chat latest
Brand: OpenAI
Price: 1.750000 USD

Gemini 3.1 Pro preview vs GPT 5.3 Chat latest: Gemini 3.1 Pro preview is cheaper by 14% on average. Gemini 3.1 Pro preview from Google Vertex AI (1,048,576-token context, reasoning, tool calls) vs. GPT 5.3 Chat latest from OpenAI (128,000-token context, reasoning, tool calls). Use Agent Command Center to A/B both in shadow mode and pick the winner per workload.

Side-by-side cost

Live workload comparison

Same workload run through both models. The cheaper one is highlighted.

Input tokens / request3,000

01,048,576

Output tokens / request400

065,536

Requests / day5,000

01,000,000

Gemini 3.1 Pro previewCheaper

Google Vertex AI

$1,644/mo

Input $2.00/M · Output $12.00/M

GPT 5.3 Chat latest

OpenAI

$1,651/mo

Input $1.75/M · Output $14.00/M

At this workload, Gemini 3.1 Pro preview is 0% cheaper than GPT 5.3 Chat latest — a savings of $7.61/month ($91.31/year).

Crossover: GPT 5.3 Chat latest is cheaper when output/input ≤ 0.13 (input-heavy workloads — RAG, retrieval). Gemini 3.1 Pro preview wins above (long-form generation).

Current workload ratio: 0.13 (400/3000)

Production recipe — Agent Command Center

strategy: cost-optimized
primary:
  model: gemini-3-1-pro-preview
  provider: vertex-ai
fallback:
  model: gpt-5-3-chat-latest
  provider: openai
shadow: { sample_rate: 0.05 }   # mirror 5% of traffic to compare quality live

Get started free →Routing docs ↗

	Gemini 3.1 Pro preview Google Vertex AI	GPT 5.3 Chat latest OpenAI
Input price	$2.00/M	$1.75/M
Output price	$12.00/M	$14.00/M
Context window	1,048,576	128,000
Max output	65,536	16,384
Function calling	✓	✓
Vision	✓	✓
Audio input	✓	—
Reasoning	✓	✓
Prompt caching	✓	✓
Structured output	✓	✓
Pricing verified	May 12, 2026	May 12, 2026