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gemini-2.5-flash vs gpt-5-nano — cost comparison

Google gemini-2.5-flash vs OpenAI gpt-5-nano — list pricing, worked examples, interactive calculator. Verified 2026-05-15.

TL;DR. gpt-5-nano is cheaper on both input (3.0×) and output (6.3×).

Headline pricing

	gemini-2.5-flash	gpt-5-nano
Input / 1M tokens	$0.30	$0.10
Output / 1M tokens	$2.50	$0.40
Cache write / 1M tokens	—	—
Cache read / 1M tokens	—	—

Sources: Google, OpenAI. Verified 2026-05-15. Re-verify before relying on these numbers for budget commits.

Worked examples (per call, list pricing)

Workload shape	gemini-2.5-flash	gpt-5-nano	Cheaper
1k in + 500 out (tool call)	$0.0015	$0.000300	gpt-5-nano (5.2× cheaper)
10k in + 1k out (RAG)	$0.0055	$0.0014	gpt-5-nano (3.9× cheaper)
100k in + 1k out (long doc)	$0.0325	$0.0104	gpt-5-nano (3.1× cheaper)
2k in + 4k out (long gen)	$0.0106	$0.0018	gpt-5-nano (5.9× cheaper)

Interactive calculator

Calls per month

Prompt tokens / call

Completion tokens / call

(reserved)

How to choose between gemini-2.5-flash and gpt-5-nano

Quality first. Cost only matters if both models clear your quality bar. Run a 30-call eval on real prompts before committing to the cheaper option. If quality is unequal, the price difference is a distraction.
Match price to call shape. gemini-2.5-flash costs $0.30 in / $2.50 out. gpt-5-nano costs $0.10 in / $0.40 out. Workloads that are completion-heavy weigh output prices more.
Latency may matter more than dollars. Some providers are 5-10× faster at the same price tier. If you're below a few thousand calls/day, latency UX usually beats price.

Track what you're actually spending on each

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Related comparisons

Google full pricing · OpenAI full pricing · All-provider comparison

About this page. Built and maintained by an autonomous AI agent under KS Elevated Solutions LLC. Pricing data comes from each provider's published pricing page, verified 2026-05-15; the same table is bundled in the tokenmark npm package. No fabricated reviews, ratings, or social proof. See full AI disclosure.