How LLM API Pricing Works

Tokens, input vs output, context windows — why the same task can cost 50× more on one model than another, explained simply.

HomeAI Models › GPT-4o mini vs Gemini 2.5 Flash

GPT-4o mini vs Gemini 2.5 Flash: price comparison

Real 2026 API prices side by side, with the total cost of a typical 10M-input / 3M-output monthly workload.

Price & cost at a glance

GPT-4o miniGemini 2.5 Flash
Input / 1M tokens$0.15$0.3
Output / 1M tokens$0.6$2.5
Context window128K1000K
Cost — 10M in + 3M out$3.3$10.5

Green = cheaper / larger. Prices per 1M tokens, USD. Snapshot 2026 — verify with the provider.

Which is cheaper?

GPT-4o mini is the cheaper option on a 10M-in / 3M-out workload — about $3.3/mo versus $10.5 for Gemini 2.5 Flash (~3.2× difference). Because output tokens are billed higher, the model with the lower output price usually wins as your responses get longer.

Run your own token mix in the cost calculator, or see each model in depth: GPT-4o mini · Gemini 2.5 Flash.

Frequently asked

Is GPT-4o mini or Gemini 2.5 Flash cheaper?

At a typical 10M input + 3M output tokens per month, GPT-4o mini costs about $3.3 versus $10.5 for Gemini 2.5 Flash — GPT-4o mini is roughly 3.2x cheaper on this workload. Your ratio of input to output tokens changes the gap.

What's the price difference between GPT-4o mini and Gemini 2.5 Flash?

GPT-4o mini is $0.15/$0.6 per 1M input/output tokens; Gemini 2.5 Flash is $0.3/$2.5. Output tokens usually dominate a bill, so compare the output price first.

Which has the bigger context window, GPT-4o mini or Gemini 2.5 Flash?

GPT-4o mini supports about 128K tokens and Gemini 2.5 Flash about 1000K. A bigger window costs more per call because every token in context is billed.

Educational estimates — not affiliated with any provider.