GPT-5.4 mini vs Gemini 2.5 Flash: API Cost Comparison (2026)
GPT-5.4 mini or Gemini 2.5 Flash? Instead of comparing list prices, we compute the same workload on both (prices verified 2026-07-09). Spoiler: Gemini 2.5 Flash wins on raw cost in fewer scenarios — but "when to pick each" matters more than the winner. Compare them live in the calculator.
| Rate per 1M tokens | GPT-5.4 mini | Gemini 2.5 Flash |
|---|---|---|
| Input | $0.75 | $0.30 |
| Cached input | $0.08 | $0.03 |
| Output | $4.50 | $2.50 |
Same workload, both models
| Monthly scenario | GPT-5.4 mini | Gemini 2.5 Flash | Difference |
|---|---|---|---|
| Support chatbot (150k requests, 400 in / 300 out tokens) | $247.50 | $130.50 | 47% in favor of Gemini 2.5 Flash |
| Document workflow (22k runs, 3,000 in / 400 out tokens) | $89.10 | $41.80 | 53% in favor of Gemini 2.5 Flash |
| High-volume classifier (1M requests, 300 in / 10 out tokens) | $270.00 | $115.00 | 57% in favor of Gemini 2.5 Flash |
Your token shape decides: input-heavy workloads (documents, RAG) amplify the input-rate gap; output-heavy ones (content generation) weigh the output rate. Run your exact mix in the calculator with both preselected.
When to pick each
- Gemini 2.5 Flash — when per-token cost rules: high volume, verifiable tasks, tight budgets. It comes out 47–57% cheaper in these scenarios.
- GPT-5.4 mini — when the premium buys something you need (quality on your specific task, context, ecosystem). The only honest way to know: test your real case on both with a small sample.
- Both — the winning production pattern is often routing: easy requests to the cheap one, hard ones to the strong one.
Related guides: how AI API pricing works and how to reduce LLM costs.
Prices verified on 2026-07-09 against the provider's official pricing page. Estimates are for planning purposes only — always confirm current pricing with the provider.