o4-mini vs Gemini 3 Flash

OpenAI's o4-mini against Google's Gemini 3 Flash — pricing, benchmarks, context, and best use cases compared side by side.

Last updated March 2026 · Compare other models
Quick Verdict

o4-mini leads on quality (Elo 1350 vs 1340), while Gemini 3 Flash compensates with 36% lower pricing. Gemini 3 Flash offers a larger context window (1M vs 200K).

o4-mini
OpenAI
Gemini 3 Flash
Google
Input Price $1.10/1M $0.50/1M
Output Price $4.40/1M $3.00/1M
Blended Price $2.75/1M $1.75/1M
LMSYS Elo 1350 1340
Context Window 200,000 1,000,000
Provider OpenAI Google

Pricing breakdown

When comparing LLM API pricing, Gemini 3 Flash charges $0.50 per 1M input tokens compared to o4-mini's $1.10 — a 55% difference. For output tokens, Gemini 3 Flash costs $3.00/1M versus $4.40/1M for o4-mini. On a blended basis (averaging input and output), Gemini 3 Flash comes in at $1.75/1M tokens versus $2.75/1M for o4-mini.

Quality & benchmarks

On the LMSYS Chatbot Arena leaderboard — a crowd-sourced benchmark based on blind human preference voting — o4-mini scores 1350 Elo compared to Gemini 3 Flash's 1340, a 10-point advantage. While o4-mini has the edge, both models are competitive. o4-mini excels at cost-effective reasoning, coding assistance, and structured problem-solving, while Gemini 3 Flash is well-suited for high-throughput processing, real-time applications, and cost-sensitive pipelines.

Context window comparison

Gemini 3 Flash provides a significantly larger context window at 1M tokens compared to o4-mini's 200K tokens — 5.0x more capacity for processing long documents, large codebases, or extended conversations. With 1M tokens, Gemini 3 Flash can handle entire books, repositories, or multi-document analysis in a single prompt.

Monthly cost estimate

Adjust the sliders to see how costs compare for your workload.

o4-mini
per month
Gemini 3 Flash
per month

Choose o4-mini if you need...

Budget reasoning model
Great quality-to-cost for chain-of-thought
Fast inference for a reasoning model

Choose Gemini 3 Flash if you need...

Fast and affordable
1M context at flash-tier pricing
Good for high-throughput pipelines

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