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

For a typical request (10,000 input + 2,000 output tokens), GPT-4o mini is cheaper — about 66% less, or roughly $530 saved per 100,000 requests. Gemini 2.5 Flash runs $0.3/$2.5 per 1M input/output tokens; GPT-4o mini runs $0.15/$0.6.

Which has the larger context window?

Gemini 2.5 Flash, at 1,000,000 tokens versus 128,000.

How accurate are these token counts?

Gemini 2.5 Flash: Approximated with o200k_base; drift typically ~3% on English and code. GPT-4o mini: Exact tokenization via the canonical OpenAI vocab (o200k_base). The dollar math itself is exact once the token count is known.

Gemini 2.5 Flash vs GPT-4o mini: pricing & cost comparison

On input tokens, GPT-4o mini is the cheaper of the two — 50% less per million ($0.3 vs $0.15). On output, GPT-4o mini is 76% cheaper ($2.5 vs $0.6) — and since output is usually the dominant cost driver, that gap matters more than it looks.

Side by side

	Gemini 2.5 Flash	GPT-4o mini
Input / 1M tokens	$0.3	$0.15
Output / 1M tokens	$2.5	$0.6
Context window	1,000,000	128,000
Token-count accuracy	±3%	exact
Cost — 10,000 input + 2,000 output tokens	$0.008	$0.0027

What a real request costs

Take a representative turn — 10,000 input + 2,000 output tokens. Gemini 2.5 Flash comes to $0.008, GPT-4o mini to $0.0027. Across 100,000 requests that's a $530 swing in favour of GPT-4o mini. To run the numbers on your actual prompt, paste it into the calculator and toggle Compare across all models.

Close call — decide on output cost

Gemini 2.5 Flash and GPT-4o mini are close enough on price that the tie-breakers matter more than the headline rate. Output tokens are usually the dominant cost driver, so weigh $2.5 vs $0.6 per 1M output first, then context window — Gemini 2.5 Flash carries the larger one at 1,000,000 tokens. They're different vendors, so factor in a small tokenizer calibration buffer on whichever side isn't exact.

See the full breakdown on the dedicated pages for Gemini 2.5 Flash and GPT-4o mini.

FAQ

Is Gemini 2.5 Flash or GPT-4o mini cheaper?: For a typical request (10,000 input + 2,000 output tokens), GPT-4o mini is cheaper — about 66% less, or roughly $530 saved per 100,000 requests. Gemini 2.5 Flash runs $0.3/$2.5 per 1M input/output tokens; GPT-4o mini runs $0.15/$0.6.
Which has the larger context window?: Gemini 2.5 Flash, at 1,000,000 tokens versus 128,000.
How accurate are these token counts?: Gemini 2.5 Flash: Approximated with o200k_base; drift typically ~3% on English and code. GPT-4o mini: Exact tokenization via the canonical OpenAI vocab (o200k_base). The dollar math itself is exact once the token count is known.

Both prices are computed from tokenmath's verified pricing table. Rates sourced from ai.google.dev and openai.com, verified 2026-05-18. Vendor pricing changes often — confirm before you commit.