Gemini 3.5 Flash vs GPT-4o mini: token pricing & cost compared (July 2026)

How Gemini 3.5 Flash (Google) and GPT-4o mini (OpenAI) actually compare on price — input, output, and total monthly cost at the MAU you care about. Updated against live OpenRouter pricing.

Google

Gemini 3.5 Flash

Input: $1.50 / 1M tokens
Output: $9.00 / 1M tokens
Output / Input ratio: 6.0×
Context window: 1,048.576K

OpenAI

GPT-4o mini

Input: $0.15 / 1M tokens
Output: $0.60 / 1M tokens
Output / Input ratio: 4.0×
Context window: 128K

The short answer

GPT-4o mini is cheaper across the board for typical workloads.

Token pricing side-by-side

Gemini 3.5 Flash
GPT-4o mini

Cost at your usage

Avg input tokens / call

Avg output tokens / call

Calls per active user / day: 5

Active days / month: 20

MAU: 1,000

Gemini 3.5 Flash

Per call

$0.00525

Per user / mo

$0.5250

Total / mo

$525

GPT-4o mini

Per call

$0.00037

Per user / mo

$0.0375

Total / mo

$37

GPT-4o mini is cheaper by $0.4875/user/month — a saving of $487/month at 1,000 MAU.

Total monthly bill across MAU

Gemini 3.5 Flash
GPT-4o mini

Same usage profile applied to both models; only the per-token price differs.

Run this against your real numbers

The mini-calculator above is a preview. Use the full tools to model power-user blast radius, gross margin, and 12-month spend forecasts.

Other comparisons

Gemini 3.5 Flash vs Claude Haiku 4.5 DeepSeek V4 Flash vs GPT-4o mini DeepSeek V4 Flash vs Gemini 3.5 Flash GPT-4o mini vs Claude 3.5 Haiku GPT-4o mini vs Gemini 2.5 Flash GPT-4o mini vs Claude Haiku 4.5

Comparing Gemini 3.5 Flash vs GPT-4o mini on price alone never tells the whole story — output-token weighting, context length, and your usage profile change the answer dramatically. Use the calculators below for the full picture.